Fast double-to-ascii conversion.
Review URL: http://codereview.chromium.org/866002 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4106 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
parent
347f099c80
commit
8814064337
@ -63,6 +63,7 @@ SOURCES = {
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full-codegen.cc
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func-name-inferrer.cc
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global-handles.cc
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grisu3.cc
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handles.cc
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hashmap.cc
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heap-profiler.cc
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119
src/cached_powers.h
Normal file
119
src/cached_powers.h
Normal file
@ -0,0 +1,119 @@
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// Copyright 2010 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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||||
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_CACHED_POWERS_H_
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#define V8_CACHED_POWERS_H_
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#include "diy_fp.h"
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namespace v8 {
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namespace internal {
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struct CachedPower {
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uint64_t significand;
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int16_t binary_exponent;
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int16_t decimal_exponent;
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};
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// The following defines implement the interface between this file and the
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// generated 'powers_ten.h'.
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// GRISU_CACHE_NAME(1) contains all possible cached powers.
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// GRISU_CACHE_NAME(i) contains GRISU_CACHE_NAME(1) where only every 'i'th
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// element is kept. More formally GRISU_CACHE_NAME(i) contains the elements j*i
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// with 0 <= j < k with k such that j*k < the size of GRISU_CACHE_NAME(1).
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// The higher 'i' is the fewer elements we use.
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// Given that there are less elements, the exponent-distance between two
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// elements in the cache grows. The variable GRISU_CACHE_MAX_DISTANCE(i) stores
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// the maximum distance between two elements.
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#define GRISU_CACHE_STRUCT CachedPower
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#define GRISU_CACHE_NAME(i) kCachedPowers##i
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#define GRISU_CACHE_MAX_DISTANCE(i) kCachedPowersMaxDistance##i
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#define GRISU_CACHE_OFFSET kCachedPowerOffset
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#define GRISU_UINT64_C V8_2PART_UINT64_C
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// The following include imports the precompiled cached powers.
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#include "powers_ten.h" // NOLINT
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static const double kD_1_LOG2_10 = 0.30102999566398114; // 1 / lg(10)
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// We can't use a function since we reference variables depending on the 'i'.
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// This way the compiler is able to see at compile time that only one
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// cache-array variable is used and thus can remove all the others.
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#define COMPUTE_FOR_CACHE(i) \
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if (!found && (gamma - alpha + 1 >= GRISU_CACHE_MAX_DISTANCE(i))) { \
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int kQ = DiyFp::kSignificandSize; \
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double k = ceiling((alpha - e + kQ - 1) * kD_1_LOG2_10); \
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int index = (GRISU_CACHE_OFFSET + static_cast<int>(k) - 1) / i + 1; \
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cached_power = GRISU_CACHE_NAME(i)[index]; \
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found = true; \
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} \
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static void GetCachedPower(int e, int alpha, int gamma, int* mk, DiyFp* c_mk) {
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// The following if statement should be optimized by the compiler so that only
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// one array is referenced and the others are not included in the object file.
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bool found = false;
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CachedPower cached_power;
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COMPUTE_FOR_CACHE(20);
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COMPUTE_FOR_CACHE(19);
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COMPUTE_FOR_CACHE(18);
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COMPUTE_FOR_CACHE(17);
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COMPUTE_FOR_CACHE(16);
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COMPUTE_FOR_CACHE(15);
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COMPUTE_FOR_CACHE(14);
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COMPUTE_FOR_CACHE(13);
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COMPUTE_FOR_CACHE(12);
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COMPUTE_FOR_CACHE(11);
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COMPUTE_FOR_CACHE(10);
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COMPUTE_FOR_CACHE(9);
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COMPUTE_FOR_CACHE(8);
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COMPUTE_FOR_CACHE(7);
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COMPUTE_FOR_CACHE(6);
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COMPUTE_FOR_CACHE(5);
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COMPUTE_FOR_CACHE(4);
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COMPUTE_FOR_CACHE(3);
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COMPUTE_FOR_CACHE(2);
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COMPUTE_FOR_CACHE(1);
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if (!found) {
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UNIMPLEMENTED();
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// Silence compiler warnings.
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cached_power.significand = 0;
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cached_power.binary_exponent = 0;
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cached_power.decimal_exponent = 0;
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}
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*c_mk = DiyFp(cached_power.significand, cached_power.binary_exponent);
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*mk = cached_power.decimal_exponent;
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ASSERT((alpha <= c_mk->e() + e) && (c_mk->e() + e <= gamma));
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}
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#undef GRISU_REDUCTION
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#undef GRISU_CACHE_STRUCT
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#undef GRISU_CACHE_NAME
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#undef GRISU_CACHE_MAX_DISTANCE
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#undef GRISU_CACHE_OFFSET
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#undef GRISU_UINT64_C
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} } // namespace v8::internal
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#endif // V8_CACHED_POWERS_H_
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22
src/checks.h
22
src/checks.h
@ -80,6 +80,7 @@ static inline void CheckEqualsHelper(const char* file, int line,
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}
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}
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// Helper function used by the CHECK_EQ function when given int64_t
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// arguments. Should not be called directly.
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static inline void CheckEqualsHelper(const char* file, int line,
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@ -202,6 +203,27 @@ static inline void CheckEqualsHelper(const char* file,
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}
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static inline void CheckNonEqualsHelper(const char* file,
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int line,
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const char* expected_source,
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double expected,
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const char* value_source,
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double value) {
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// Force values to 64 bit memory to truncate 80 bit precision on IA32.
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volatile double* exp = new double[1];
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*exp = expected;
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volatile double* val = new double[1];
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*val = value;
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if (*exp == *val) {
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V8_Fatal(file, line,
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"CHECK_NE(%s, %s) failed\n# Value: %f",
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expected_source, value_source, *val);
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}
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delete[] exp;
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delete[] val;
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}
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namespace v8 {
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class Value;
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template <class T> class Handle;
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@ -31,6 +31,7 @@
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#include "conversions-inl.h"
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#include "factory.h"
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#include "grisu3.h"
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#include "scanner.h"
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namespace v8 {
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@ -382,8 +383,17 @@ const char* DoubleToCString(double v, Vector<char> buffer) {
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int decimal_point;
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int sign;
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char* decimal_rep = dtoa(v, 0, 0, &decimal_point, &sign, NULL);
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int length = StrLength(decimal_rep);
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char* decimal_rep;
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bool used_dtoa = false;
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char grisu_buffer[kGrisu3MaximalLength + 1];
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int length;
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if (grisu3(v, grisu_buffer, &sign, &length, &decimal_point)) {
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decimal_rep = grisu_buffer;
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} else {
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decimal_rep = dtoa(v, 0, 0, &decimal_point, &sign, NULL);
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used_dtoa = true;
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length = StrLength(decimal_rep);
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}
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if (sign) builder.AddCharacter('-');
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@ -418,7 +428,7 @@ const char* DoubleToCString(double v, Vector<char> buffer) {
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builder.AddFormatted("%d", exponent);
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}
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freedtoa(decimal_rep);
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if (used_dtoa) freedtoa(decimal_rep);
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}
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}
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return builder.Finalize();
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136
src/diy_fp.h
Normal file
136
src/diy_fp.h
Normal file
@ -0,0 +1,136 @@
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// Copyright 2010 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
|
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_DIY_FP_H_
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#define V8_DIY_FP_H_
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namespace v8 {
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namespace internal {
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// This "Do It Yourself Floating Point" class implements a floating-point number
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// with a uint64 significand and an int exponent. Normalized DiyFp numbers will
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// have the most significant bit of the significand set.
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// Multiplication and Subtraction do not normalize their results.
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// DiyFp are not designed to contain special doubles (NaN and Infinity).
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class DiyFp {
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public:
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static const int kSignificandSize = 64;
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DiyFp() : f_(0), e_(0) {}
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DiyFp(uint64_t f, int e) : f_(f), e_(e) {}
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// this = this - other.
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// The exponents of both numbers must be the same and the significand of this
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// must be bigger than the significand of other.
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// The result will not be normalized.
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void Subtract(const DiyFp& other) {
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ASSERT(e_ == other.e_);
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ASSERT(f_ >= other.f_);
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f_ -= other.f_;
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}
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// Returns a - b.
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// The exponents of both numbers must be the same and this must be bigger
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// than other. The result will not be normalized.
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static DiyFp Minus(const DiyFp& a, const DiyFp& b) {
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DiyFp result = a;
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result.Subtract(b);
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return result;
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}
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// this = this * other.
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void Multiply(const DiyFp& other) {
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// Simply "emulates" a 128 bit multiplication.
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// However: the resulting number only contains 64 bits. The least
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// significant 64 bits are only used for rounding the most significant 64
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// bits.
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const uint64_t kM32 = 0xFFFFFFFFu;
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uint64_t a = f_ >> 32;
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uint64_t b = f_ & kM32;
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uint64_t c = other.f_ >> 32;
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uint64_t d = other.f_ & kM32;
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uint64_t ac = a * c;
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uint64_t bc = b * c;
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uint64_t ad = a * d;
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uint64_t bd = b * d;
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uint64_t tmp = (bd >> 32) + (ad & kM32) + (bc & kM32);
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tmp += 1U << 31; // round
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uint64_t result_f = ac + (ad >> 32) + (bc >> 32) + (tmp >> 32);
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e_ += other.e_ + 64;
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f_ = result_f;
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}
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// returns a * b;
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static DiyFp Times(const DiyFp& a, const DiyFp& b) {
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DiyFp result = a;
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result.Multiply(b);
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return result;
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}
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void Normalize() {
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ASSERT(f_ != 0);
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uint64_t f = f_;
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int e = e_;
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// This method is mainly called for normalizing boundaries. In general
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// boundaries need to be shifted by 10 bits. We thus optimize for this case.
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const uint64_t k10MSBits = V8_2PART_UINT64_C(0xFFC00000, 00000000);
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while ((f & k10MSBits) == 0) {
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f <<= 10;
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e -= 10;
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}
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while ((f & kUint64MSB) == 0) {
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f <<= 1;
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e--;
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}
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f_ = f;
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e_ = e;
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}
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static DiyFp Normalize(const DiyFp& a) {
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DiyFp result = a;
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result.Normalize();
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return result;
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}
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uint64_t f() const { return f_; }
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int e() const { return e_; }
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void set_f(uint64_t new_value) { f_ = new_value; }
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void set_e(int new_value) { e_ = new_value; }
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private:
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static const uint64_t kUint64MSB = V8_2PART_UINT64_C(0x80000000, 00000000);
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uint64_t f_;
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int e_;
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};
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} } // namespace v8::internal
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#endif // V8_DIY_FP_H_
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169
src/double.h
Normal file
169
src/double.h
Normal file
@ -0,0 +1,169 @@
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// Copyright 2010 the V8 project authors. All rights reserved.
|
||||
// Redistribution and use in source and binary forms, with or without
|
||||
// modification, are permitted provided that the following conditions are
|
||||
// met:
|
||||
//
|
||||
// * Redistributions of source code must retain the above copyright
|
||||
// notice, this list of conditions and the following disclaimer.
|
||||
// * Redistributions in binary form must reproduce the above
|
||||
// copyright notice, this list of conditions and the following
|
||||
// disclaimer in the documentation and/or other materials provided
|
||||
// with the distribution.
|
||||
// * Neither the name of Google Inc. nor the names of its
|
||||
// contributors may be used to endorse or promote products derived
|
||||
// from this software without specific prior written permission.
|
||||
//
|
||||
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
||||
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
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#ifndef V8_DOUBLE_H_
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#define V8_DOUBLE_H_
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#include "diy_fp.h"
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namespace v8 {
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namespace internal {
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// We assume that doubles and uint64_t have the same endianness.
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static uint64_t double_to_uint64(double d) { return bit_cast<uint64_t>(d); }
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static double uint64_to_double(uint64_t d64) { return bit_cast<double>(d64); }
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// Helper functions for doubles.
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class Double {
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public:
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static const uint64_t kSignMask = V8_2PART_UINT64_C(0x80000000, 00000000);
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static const uint64_t kExponentMask = V8_2PART_UINT64_C(0x7FF00000, 00000000);
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static const uint64_t kSignificandMask =
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V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
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static const uint64_t kHiddenBit = V8_2PART_UINT64_C(0x00100000, 00000000);
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Double() : d64_(0) {}
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explicit Double(double d) : d64_(double_to_uint64(d)) {}
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explicit Double(uint64_t d64) : d64_(d64) {}
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DiyFp AsDiyFp() const {
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ASSERT(!IsSpecial());
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return DiyFp(Significand(), Exponent());
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}
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// this->Significand() must not be 0.
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DiyFp AsNormalizedDiyFp() const {
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uint64_t f = Significand();
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int e = Exponent();
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|
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ASSERT(f != 0);
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||||
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// The current double could be a denormal.
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while ((f & kHiddenBit) == 0) {
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f <<= 1;
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e--;
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||||
}
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||||
// Do the final shifts in one go. Don't forget the hidden bit (the '-1').
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f <<= DiyFp::kSignificandSize - kSignificandSize - 1;
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e -= DiyFp::kSignificandSize - kSignificandSize - 1;
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return DiyFp(f, e);
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}
|
||||
|
||||
// Returns the double's bit as uint64.
|
||||
uint64_t AsUint64() const {
|
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return d64_;
|
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}
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||||
|
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int Exponent() const {
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if (IsDenormal()) return kDenormalExponent;
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||||
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||||
uint64_t d64 = AsUint64();
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int biased_e = static_cast<int>((d64 & kExponentMask) >> kSignificandSize);
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return biased_e - kExponentBias;
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||||
}
|
||||
|
||||
uint64_t Significand() const {
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uint64_t d64 = AsUint64();
|
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uint64_t significand = d64 & kSignificandMask;
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||||
if (!IsDenormal()) {
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return significand + kHiddenBit;
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} else {
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return significand;
|
||||
}
|
||||
}
|
||||
|
||||
// Returns true if the double is a denormal.
|
||||
bool IsDenormal() const {
|
||||
uint64_t d64 = AsUint64();
|
||||
return (d64 & kExponentMask) == 0;
|
||||
}
|
||||
|
||||
// We consider denormals not to be special.
|
||||
// Hence only Infinity and NaN are special.
|
||||
bool IsSpecial() const {
|
||||
uint64_t d64 = AsUint64();
|
||||
return (d64 & kExponentMask) == kExponentMask;
|
||||
}
|
||||
|
||||
bool IsNan() const {
|
||||
uint64_t d64 = AsUint64();
|
||||
return ((d64 & kExponentMask) == kExponentMask) &&
|
||||
((d64 & kSignificandMask) != 0);
|
||||
}
|
||||
|
||||
|
||||
bool IsInfinite() const {
|
||||
uint64_t d64 = AsUint64();
|
||||
return ((d64 & kExponentMask) == kExponentMask) &&
|
||||
((d64 & kSignificandMask) == 0);
|
||||
}
|
||||
|
||||
|
||||
int Sign() const {
|
||||
uint64_t d64 = AsUint64();
|
||||
return (d64 & kSignMask) == 0? 1: -1;
|
||||
}
|
||||
|
||||
|
||||
// Returns the two boundaries of this.
|
||||
// The bigger boundary (m_plus) is normalized. The lower boundary has the same
|
||||
// exponent as m_plus.
|
||||
void NormalizedBoundaries(DiyFp* out_m_minus, DiyFp* out_m_plus) const {
|
||||
DiyFp v = this->AsDiyFp();
|
||||
bool significand_is_zero = (v.f() == kHiddenBit);
|
||||
DiyFp m_plus = DiyFp::Normalize(DiyFp((v.f() << 1) + 1, v.e() - 1));
|
||||
DiyFp m_minus;
|
||||
if (significand_is_zero && v.e() != kDenormalExponent) {
|
||||
// The boundary is closer. Think of v = 1000e10 and v- = 9999e9.
|
||||
// Then the boundary (== (v - v-)/2) is not just at a distance of 1e9 but
|
||||
// at a distance of 1e8.
|
||||
// The only exception is for the smallest normal: the largest denormal is
|
||||
// at the same distance as its successor.
|
||||
// Note: denormals have the same exponent as the smallest normals.
|
||||
m_minus = DiyFp((v.f() << 2) - 1, v.e() - 2);
|
||||
} else {
|
||||
m_minus = DiyFp((v.f() << 1) - 1, v.e() - 1);
|
||||
}
|
||||
m_minus.set_f(m_minus.f() << (m_minus.e() - m_plus.e()));
|
||||
m_minus.set_e(m_plus.e());
|
||||
*out_m_plus = m_plus;
|
||||
*out_m_minus = m_minus;
|
||||
}
|
||||
|
||||
double value() const { return uint64_to_double(d64_); }
|
||||
|
||||
private:
|
||||
static const int kSignificandSize = 52; // Excludes the hidden bit.
|
||||
static const int kExponentBias = 0x3FF + kSignificandSize;
|
||||
static const int kDenormalExponent = -kExponentBias + 1;
|
||||
|
||||
uint64_t d64_;
|
||||
};
|
||||
|
||||
} } // namespace v8::internal
|
||||
|
||||
#endif // V8_DOUBLE_H_
|
@ -98,6 +98,11 @@ typedef byte* Address;
|
||||
#define V8_PTR_PREFIX ""
|
||||
#endif // V8_HOST_ARCH_64_BIT
|
||||
|
||||
// The following macro works on both 32 and 64-bit platforms.
|
||||
// Usage: instead of writing 0x1234567890123456
|
||||
// write V8_2PART_UINT64_C(0x12345678,90123456);
|
||||
#define V8_2PART_UINT64_C(a, b) (((static_cast<uint64_t>(a) << 32) + 0x##b##u))
|
||||
|
||||
#define V8PRIxPTR V8_PTR_PREFIX "x"
|
||||
#define V8PRIdPTR V8_PTR_PREFIX "d"
|
||||
|
||||
|
494
src/grisu3.cc
Normal file
494
src/grisu3.cc
Normal file
@ -0,0 +1,494 @@
|
||||
// Copyright 2010 the V8 project authors. All rights reserved.
|
||||
// Redistribution and use in source and binary forms, with or without
|
||||
// modification, are permitted provided that the following conditions are
|
||||
// met:
|
||||
//
|
||||
// * Redistributions of source code must retain the above copyright
|
||||
// notice, this list of conditions and the following disclaimer.
|
||||
// * Redistributions in binary form must reproduce the above
|
||||
// copyright notice, this list of conditions and the following
|
||||
// disclaimer in the documentation and/or other materials provided
|
||||
// with the distribution.
|
||||
// * Neither the name of Google Inc. nor the names of its
|
||||
// contributors may be used to endorse or promote products derived
|
||||
// from this software without specific prior written permission.
|
||||
//
|
||||
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
||||
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
||||
#include "v8.h"
|
||||
|
||||
#include "grisu3.h"
|
||||
|
||||
#include "cached_powers.h"
|
||||
#include "diy_fp.h"
|
||||
#include "double.h"
|
||||
|
||||
namespace v8 {
|
||||
namespace internal {
|
||||
|
||||
template <int alpha = -60, int gamma = -32>
|
||||
class Grisu3 {
|
||||
public:
|
||||
// Provides a decimal representation of v.
|
||||
// Returns true if it succeeds, otherwise the result can not be trusted.
|
||||
// There will be *length digits inside the buffer (not null-terminated).
|
||||
// If the function returns true then
|
||||
// v == (double) (buffer * 10^decimal_exponent).
|
||||
// The digits in the buffer are the shortest representation possible: no
|
||||
// 0.099999999999 instead of 0.1.
|
||||
// The last digit will be closest to the actual v. That is, even if several
|
||||
// digits might correctly yield 'v' when read again, the closest will be
|
||||
// computed.
|
||||
static bool grisu3(double v,
|
||||
char* buffer, int* length, int* decimal_exponent);
|
||||
|
||||
private:
|
||||
// Rounds the buffer according to the rest.
|
||||
// If there is too much imprecision to round then false is returned.
|
||||
// Similarily false is returned when the buffer is not within Delta.
|
||||
static bool RoundWeed(char* buffer, int len, uint64_t wp_W, uint64_t Delta,
|
||||
uint64_t rest, uint64_t ten_kappa, uint64_t ulp);
|
||||
// Dispatches to the a specialized digit-generation routine. The chosen
|
||||
// routine depends on w.e (which in turn depends on alpha and gamma).
|
||||
// Currently there is only one digit-generation routine, but it would be easy
|
||||
// to add others.
|
||||
static bool DigitGen(DiyFp low, DiyFp w, DiyFp high,
|
||||
char* buffer, int* len, int* kappa);
|
||||
// Generates w's digits. The result is the shortest in the interval low-high.
|
||||
// All DiyFp are assumed to be imprecise and this function takes this
|
||||
// imprecision into account. If the function cannot compute the best
|
||||
// representation (due to the imprecision) then false is returned.
|
||||
static bool DigitGen_m60_m32(DiyFp low, DiyFp w, DiyFp high,
|
||||
char* buffer, int* length, int* kappa);
|
||||
};
|
||||
|
||||
|
||||
template<int alpha, int gamma>
|
||||
bool Grisu3<alpha, gamma>::grisu3(double v,
|
||||
char* buffer,
|
||||
int* length,
|
||||
int* decimal_exponent) {
|
||||
DiyFp w = Double(v).AsNormalizedDiyFp();
|
||||
// boundary_minus and boundary_plus are the boundaries between v and its
|
||||
// neighbors. Any number strictly between boundary_minus and boundary_plus
|
||||
// will round to v when read as double.
|
||||
// Grisu3 will never output representations that lie exactly on a boundary.
|
||||
DiyFp boundary_minus, boundary_plus;
|
||||
Double(v).NormalizedBoundaries(&boundary_minus, &boundary_plus);
|
||||
ASSERT(boundary_plus.e() == w.e());
|
||||
DiyFp ten_mk; // Cached power of ten: 10^-k
|
||||
int mk; // -k
|
||||
GetCachedPower(w.e() + DiyFp::kSignificandSize, alpha, gamma, &mk, &ten_mk);
|
||||
ASSERT(alpha <= w.e() + ten_mk.e() + DiyFp::kSignificandSize &&
|
||||
gamma >= w.e() + ten_mk.e() + DiyFp::kSignificandSize);
|
||||
// Note that ten_mk is only an approximation of 10^-k. A DiyFp only contains a
|
||||
// 64 bit significand and ten_mk is thus only precise up to 64 bits.
|
||||
|
||||
// The DiyFp::Times procedure rounds its result, and ten_mk is approximated
|
||||
// too. The variable scaled_w (as well as scaled_boundary_minus/plus) are now
|
||||
// off by a small amount.
|
||||
// In fact: scaled_w - w*10^k < 1ulp (unit in the last place) of scaled_w.
|
||||
// In other words: let f = scaled_w.f() and e = scaled_w.e(), then
|
||||
// (f-1) * 2^e < w*10^k < (f+1) * 2^e
|
||||
DiyFp scaled_w = DiyFp::Times(w, ten_mk);
|
||||
ASSERT(scaled_w.e() ==
|
||||
boundary_plus.e() + ten_mk.e() + DiyFp::kSignificandSize);
|
||||
// In theory it would be possible to avoid some recomputations by computing
|
||||
// the difference between w and boundary_minus/plus (a power of 2) and to
|
||||
// compute scaled_boundary_minus/plus by subtracting/adding from
|
||||
// scaled_w. However the code becomes much less readable and the speed
|
||||
// enhancements are not terriffic.
|
||||
DiyFp scaled_boundary_minus = DiyFp::Times(boundary_minus, ten_mk);
|
||||
DiyFp scaled_boundary_plus = DiyFp::Times(boundary_plus, ten_mk);
|
||||
|
||||
// DigitGen will generate the digits of scaled_w. Therefore we have
|
||||
// v == (double) (scaled_w * 10^-mk).
|
||||
// Set decimal_exponent == -mk and pass it to DigitGen. If scaled_w is not an
|
||||
// integer than it will be updated. For instance if scaled_w == 1.23 then
|
||||
// the buffer will be filled with "123" und the decimal_exponent will be
|
||||
// decreased by 2.
|
||||
int kappa;
|
||||
bool result = DigitGen(scaled_boundary_minus, scaled_w, scaled_boundary_plus,
|
||||
buffer, length, &kappa);
|
||||
*decimal_exponent = -mk + kappa;
|
||||
return result;
|
||||
}
|
||||
|
||||
// Generates the digits of input number w.
|
||||
// w is a floating-point number (DiyFp), consisting of a significand and an
|
||||
// exponent. Its exponent is bounded by alpha and gamma. Typically alpha >= -63
|
||||
// and gamma <= 3.
|
||||
// Returns false if it fails, in which case the generated digits in the buffer
|
||||
// should not be used.
|
||||
// Preconditions:
|
||||
// * low, w and high are correct up to 1 ulp (unit in the last place). That
|
||||
// is, their error must be less that a unit of their last digits.
|
||||
// * low.e() == w.e() == high.e()
|
||||
// * low < w < high, and taking into account their error: low~ <= high~
|
||||
// * alpha <= w.e() <= gamma
|
||||
// Postconditions: returns false if procedure fails.
|
||||
// otherwise:
|
||||
// * buffer is not null-terminated, but len contains the number of digits.
|
||||
// * buffer contains the shortest possible decimal digit-sequence
|
||||
// such that LOW < buffer * 10^kappa < HIGH, where LOW and HIGH are the
|
||||
// correct values of low and high (without their error).
|
||||
// * if more than one decimal representation gives the minimal number of
|
||||
// decimal digits then the one closest to W (where W is the correct value
|
||||
// of w) is chosen.
|
||||
// Remark: this procedure takes into account the imprecision of its input
|
||||
// numbers. If the precision is not enough to guarantee all the postconditions
|
||||
// then false is returned. This usually happens rarely (~0.5%).
|
||||
template<int alpha, int gamma>
|
||||
bool Grisu3<alpha, gamma>::DigitGen(DiyFp low,
|
||||
DiyFp w,
|
||||
DiyFp high,
|
||||
char* buffer,
|
||||
int* len,
|
||||
int* kappa) {
|
||||
ASSERT(low.e() == w.e() && w.e() == high.e());
|
||||
ASSERT(low.f() + 1 <= high.f() - 1);
|
||||
ASSERT(alpha <= w.e() && w.e() <= gamma);
|
||||
// The following tests use alpha and gamma to avoid unnecessary dynamic tests.
|
||||
if ((alpha >= -60 && gamma <= -32) || // -60 <= w.e() <= -32
|
||||
(alpha <= -32 && gamma >= -60 && // Alpha/gamma overlaps -60/-32 region.
|
||||
-60 <= w.e() && w.e() <= -32)) {
|
||||
return DigitGen_m60_m32(low, w, high, buffer, len, kappa);
|
||||
} else {
|
||||
// A simple adaption of the special case -60/-32 would allow greater ranges
|
||||
// of alpha/gamma and thus reduce the number of precomputed cached powers of
|
||||
// ten.
|
||||
UNIMPLEMENTED();
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
static const uint32_t kTen4 = 10000;
|
||||
static const uint32_t kTen5 = 100000;
|
||||
static const uint32_t kTen6 = 1000000;
|
||||
static const uint32_t kTen7 = 10000000;
|
||||
static const uint32_t kTen8 = 100000000;
|
||||
static const uint32_t kTen9 = 1000000000;
|
||||
|
||||
// Returns the biggest power of ten that is <= than the given number. We
|
||||
// furthermore receive the maximum number of bits 'number' has.
|
||||
// If number_bits == 0 then 0^-1 is returned
|
||||
// The number of bits must be <= 32.
|
||||
static void BiggestPowerTen(uint32_t number,
|
||||
int number_bits,
|
||||
uint32_t* power,
|
||||
int* exponent) {
|
||||
switch (number_bits) {
|
||||
case 32:
|
||||
case 31:
|
||||
case 30:
|
||||
if (kTen9 <= number) {
|
||||
*power = kTen9;
|
||||
*exponent = 9;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 29:
|
||||
case 28:
|
||||
case 27:
|
||||
if (kTen8 <= number) {
|
||||
*power = kTen8;
|
||||
*exponent = 8;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 26:
|
||||
case 25:
|
||||
case 24:
|
||||
if (kTen7 <= number) {
|
||||
*power = kTen7;
|
||||
*exponent = 7;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 23:
|
||||
case 22:
|
||||
case 21:
|
||||
case 20:
|
||||
if (kTen6 <= number) {
|
||||
*power = kTen6;
|
||||
*exponent = 6;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 19:
|
||||
case 18:
|
||||
case 17:
|
||||
if (kTen5 <= number) {
|
||||
*power = kTen5;
|
||||
*exponent = 5;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 16:
|
||||
case 15:
|
||||
case 14:
|
||||
if (kTen4 <= number) {
|
||||
*power = kTen4;
|
||||
*exponent = 4;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 13:
|
||||
case 12:
|
||||
case 11:
|
||||
case 10:
|
||||
if (1000 <= number) {
|
||||
*power = 1000;
|
||||
*exponent = 3;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 9:
|
||||
case 8:
|
||||
case 7:
|
||||
if (100 <= number) {
|
||||
*power = 100;
|
||||
*exponent = 2;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 6:
|
||||
case 5:
|
||||
case 4:
|
||||
if (10 <= number) {
|
||||
*power = 10;
|
||||
*exponent = 1;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 3:
|
||||
case 2:
|
||||
case 1:
|
||||
if (1 <= number) {
|
||||
*power = 1;
|
||||
*exponent = 0;
|
||||
break;
|
||||
} // else fallthrough
|
||||
case 0:
|
||||
*power = 0;
|
||||
*exponent = -1;
|
||||
break;
|
||||
default:
|
||||
// Following assignments are here to silence compiler warnings.
|
||||
*power = 0;
|
||||
*exponent = 0;
|
||||
UNREACHABLE();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
// Same comments as for DigitGen but with additional precondition:
|
||||
// -60 <= w.e() <= -32
|
||||
//
|
||||
// Say, for the sake of example, that
|
||||
// w.e() == -48, and w.f() == 0x1234567890abcdef
|
||||
// w's value can be computed by w.f() * 2^w.e()
|
||||
// We can obtain w's integral digits by simply shifting w.f() by -w.e().
|
||||
// -> w's integral part is 0x1234
|
||||
// w's fractional part is therefore 0x567890abcdef.
|
||||
// Printing w's integral part is easy (simply print 0x1234 in decimal).
|
||||
// In order to print its fraction we repeatedly multiply the fraction by 10 and
|
||||
// get each digit. Example the first digit after the comma would be computed by
|
||||
// (0x567890abcdef * 10) >> 48. -> 3
|
||||
// The whole thing becomes slightly more complicated because we want to stop
|
||||
// once we have enough digits. That is, once the digits inside the buffer
|
||||
// represent 'w' we can stop. Everything inside the interval low - high
|
||||
// represents w. However we have to pay attention to low, high and w's
|
||||
// imprecision.
|
||||
template<int alpha, int gamma>
|
||||
bool Grisu3<alpha, gamma>::DigitGen_m60_m32(DiyFp low,
|
||||
DiyFp w,
|
||||
DiyFp high,
|
||||
char* buffer,
|
||||
int* length,
|
||||
int* kappa) {
|
||||
// low, w and high are imprecise, but by less than one ulp (unit in the last
|
||||
// place).
|
||||
// If we remove (resp. add) 1 ulp from low (resp. high) we are certain that
|
||||
// the new numbers are outside of the interval we want the final
|
||||
// representation to lie in.
|
||||
// Inversely adding (resp. removing) 1 ulp from low (resp. high) would yield
|
||||
// numbers that are certain to lie in the interval. We will use this fact
|
||||
// later on.
|
||||
// We will now start by generating the digits within the uncertain
|
||||
// interval. Later we will weed out representations that lie outside the safe
|
||||
// interval and thus _might_ lie outside the correct interval.
|
||||
uint64_t unit = 1;
|
||||
DiyFp too_low = DiyFp(low.f() - unit, low.e());
|
||||
DiyFp too_high = DiyFp(high.f() + unit, high.e());
|
||||
// too_low and too_high are guaranteed to lie outside the interval we want the
|
||||
// generated number in.
|
||||
DiyFp unsafe_interval = DiyFp::Minus(too_high, too_low);
|
||||
// We now cut the input number into two parts: the integral digits and the
|
||||
// fractionals. We will not write any decimal separator though, but adapt
|
||||
// kappa instead.
|
||||
// Reminder: we are currently computing the digits (stored inside the buffer)
|
||||
// such that: too_low < buffer * 10^kappa < too_high
|
||||
// We use too_high for the digit_generation and stop as soon as possible.
|
||||
// If we stop early we effectively round down.
|
||||
DiyFp one = DiyFp(static_cast<uint64_t>(1) << -w.e(), w.e());
|
||||
// Division by one is a shift.
|
||||
uint32_t integrals = static_cast<uint32_t>(too_high.f() >> -one.e());
|
||||
// Modulo by one is an and.
|
||||
uint64_t fractionals = too_high.f() & (one.f() - 1);
|
||||
uint32_t divider;
|
||||
int divider_exponent;
|
||||
BiggestPowerTen(integrals, DiyFp::kSignificandSize - (-one.e()),
|
||||
÷r, ÷r_exponent);
|
||||
*kappa = divider_exponent + 1;
|
||||
*length = 0;
|
||||
// Loop invariant: buffer = too_high / 10^kappa (integer division)
|
||||
// The invariant holds for the first iteration: kappa has been initialized
|
||||
// with the divider exponent + 1. And the divider is the biggest power of ten
|
||||
// that is smaller than integrals.
|
||||
while (*kappa > 0) {
|
||||
int digit = integrals / divider;
|
||||
buffer[*length] = '0' + digit;
|
||||
(*length)++;
|
||||
integrals %= divider;
|
||||
(*kappa)--;
|
||||
// Note that kappa now equals the exponent of the divider and that the
|
||||
// invariant thus holds again.
|
||||
uint64_t rest =
|
||||
(static_cast<uint64_t>(integrals) << -one.e()) + fractionals;
|
||||
// Invariant: too_high = buffer * 10^kappa + DiyFp(rest, one.e())
|
||||
// Reminder: unsafe_interval.e() == one.e()
|
||||
if (rest < unsafe_interval.f()) {
|
||||
// Rounding down (by not emitting the remaining digits) yields a number
|
||||
// that lies within the unsafe interval.
|
||||
return RoundWeed(buffer, *length, DiyFp::Minus(too_high, w).f(),
|
||||
unsafe_interval.f(), rest,
|
||||
static_cast<uint64_t>(divider) << -one.e(), unit);
|
||||
}
|
||||
divider /= 10;
|
||||
}
|
||||
|
||||
// The integrals have been generated. We are at the point of the decimal
|
||||
// separator. In the following loop we simply multiply the remaining digits by
|
||||
// 10 and divide by one. We just need to pay attention to multiply associated
|
||||
// data (like the interval or 'unit'), too.
|
||||
// Instead of multiplying by 10 we multiply by 5 (cheaper operation) and
|
||||
// increase its (imaginary) exponent. At the same time we decrease the
|
||||
// divider's (one's) exponent and shift its significand.
|
||||
// Basically, if fractionals was a DiyFp (with fractionals.e == one.e):
|
||||
// fractionals.f *= 10;
|
||||
// fractionals.f >>= 1; fractionals.e++; // value remains unchanged.
|
||||
// one.f >>= 1; one.e++; // value remains unchanged.
|
||||
// and we have again fractionals.e == one.e which allows us to divide
|
||||
// fractionals.f() by one.f()
|
||||
// We simply combine the *= 10 and the >>= 1.
|
||||
while (true) {
|
||||
fractionals *= 5;
|
||||
unit *= 5;
|
||||
unsafe_interval.set_f(unsafe_interval.f() * 5);
|
||||
unsafe_interval.set_e(unsafe_interval.e() + 1); // Will be optimized out.
|
||||
one.set_f(one.f() >> 1);
|
||||
one.set_e(one.e() + 1);
|
||||
// Integer division by one.
|
||||
int digit = static_cast<int>(fractionals >> -one.e());
|
||||
buffer[*length] = '0' + digit;
|
||||
(*length)++;
|
||||
fractionals &= one.f() - 1; // Modulo by one.
|
||||
(*kappa)--;
|
||||
if (fractionals < unsafe_interval.f()) {
|
||||
return RoundWeed(buffer, *length, DiyFp::Minus(too_high, w).f() * unit,
|
||||
unsafe_interval.f(), fractionals, one.f(), unit);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
// Rounds the given generated digits in the buffer and weeds out generated
|
||||
// digits that are not in the safe interval, or where we cannot find a rounded
|
||||
// representation.
|
||||
// Input: * buffer containing the digits of too_high / 10^kappa
|
||||
// * the buffer's length
|
||||
// * distance_too_high_w == (too_high - w).f() * unit
|
||||
// * unsafe_interval == (too_high - too_low).f() * unit
|
||||
// * rest = (too_high - buffer * 10^kappa).f() * unit
|
||||
// * ten_kappa = 10^kappa * unit
|
||||
// * unit = the common multiplier
|
||||
// Output: returns true on success.
|
||||
// Modifies the generated digits in the buffer to approach (round towards) w.
|
||||
template<int alpha, int gamma>
|
||||
bool Grisu3<alpha, gamma>::RoundWeed(char* buffer,
|
||||
int length,
|
||||
uint64_t distance_too_high_w,
|
||||
uint64_t unsafe_interval,
|
||||
uint64_t rest,
|
||||
uint64_t ten_kappa,
|
||||
uint64_t unit) {
|
||||
uint64_t small_distance = distance_too_high_w - unit;
|
||||
uint64_t big_distance = distance_too_high_w + unit;
|
||||
// Let w- = too_high - big_distance, and
|
||||
// w+ = too_high - small_distance.
|
||||
// Note: w- < w < w+
|
||||
//
|
||||
// The real w (* unit) must lie somewhere inside the interval
|
||||
// ]w-; w+[ (often written as "(w-; w+)")
|
||||
|
||||
// Basically the buffer currently contains a number in the unsafe interval
|
||||
// ]too_low; too_high[ with too_low < w < too_high
|
||||
//
|
||||
// By generating the digits of too_high we got the biggest last digit.
|
||||
// In the case that w+ < buffer < too_high we try to decrement the buffer.
|
||||
// This way the buffer approaches (rounds towards) w.
|
||||
// There are 3 conditions that stop the decrementation process:
|
||||
// 1) the buffer is already below w+
|
||||
// 2) decrementing the buffer would make it leave the unsafe interval
|
||||
// 3) decrementing the buffer would yield a number below w+ and farther away
|
||||
// than the current number. In other words:
|
||||
// (buffer{-1} < w+) && w+ - buffer{-1} > buffer - w+
|
||||
// Instead of using the buffer directly we use its distance to too_high.
|
||||
// Conceptually rest ~= too_high - buffer
|
||||
while (rest < small_distance && // Negated condition 1
|
||||
unsafe_interval - rest >= ten_kappa && // Negated condition 2
|
||||
(rest + ten_kappa < small_distance || // buffer{-1} > w+
|
||||
small_distance - rest >= rest + ten_kappa - small_distance)) {
|
||||
buffer[length - 1]--;
|
||||
rest += ten_kappa;
|
||||
}
|
||||
|
||||
// We have approached w+ as much as possible. We now test if approaching w-
|
||||
// would require changing the buffer. If yes, then we have two possible
|
||||
// representations close to w, but we cannot decide which one is closer.
|
||||
if (rest < big_distance &&
|
||||
unsafe_interval - rest >= ten_kappa &&
|
||||
(rest + ten_kappa < big_distance ||
|
||||
big_distance - rest > rest + ten_kappa - big_distance)) {
|
||||
return false;
|
||||
}
|
||||
|
||||
// Weeding test.
|
||||
// The safe interval is [too_low + 2 ulp; too_high - 2 ulp]
|
||||
// Since too_low = too_high - unsafe_interval this is equivalent too
|
||||
// [too_high - unsafe_interval + 4 ulp; too_high - 2 ulp]
|
||||
// Conceptually we have: rest ~= too_high - buffer
|
||||
return (2 * unit <= rest) && (rest <= unsafe_interval - 4 * unit);
|
||||
}
|
||||
|
||||
|
||||
bool grisu3(double v, char* buffer, int* sign, int* length, int* point) {
|
||||
ASSERT(v != 0);
|
||||
ASSERT(!Double(v).IsSpecial());
|
||||
|
||||
if (v < 0) {
|
||||
v = -v;
|
||||
*sign = 1;
|
||||
} else {
|
||||
*sign = 0;
|
||||
}
|
||||
int decimal_exponent;
|
||||
bool result = Grisu3<-60, -32>::grisu3(v, buffer, length, &decimal_exponent);
|
||||
*point = *length + decimal_exponent;
|
||||
buffer[*length] = '\0';
|
||||
return result;
|
||||
}
|
||||
|
||||
} } // namespace v8::internal
|
55
src/grisu3.h
Normal file
55
src/grisu3.h
Normal file
@ -0,0 +1,55 @@
|
||||
// Copyright 2010 the V8 project authors. All rights reserved.
|
||||
// Redistribution and use in source and binary forms, with or without
|
||||
// modification, are permitted provided that the following conditions are
|
||||
// met:
|
||||
//
|
||||
// * Redistributions of source code must retain the above copyright
|
||||
// notice, this list of conditions and the following disclaimer.
|
||||
// * Redistributions in binary form must reproduce the above
|
||||
// copyright notice, this list of conditions and the following
|
||||
// disclaimer in the documentation and/or other materials provided
|
||||
// with the distribution.
|
||||
// * Neither the name of Google Inc. nor the names of its
|
||||
// contributors may be used to endorse or promote products derived
|
||||
// from this software without specific prior written permission.
|
||||
//
|
||||
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
||||
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
||||
#ifndef V8_GRISU3_H_
|
||||
#define V8_GRISU3_H_
|
||||
|
||||
namespace v8 {
|
||||
namespace internal {
|
||||
|
||||
// Grisu3 will produce at most kGrisu3MaximalLength digits. This does not
|
||||
// include the terminating '\0' character.
|
||||
static const int kGrisu3MaximalLength = 17;
|
||||
|
||||
// Provides a decimal representation of v.
|
||||
// v must satisfy v != 0 and it must not be Infinity or NaN.
|
||||
// Returns true if it succeeds, otherwise the result can not be trusted.
|
||||
// There will be *length digits inside the buffer followed by a null terminator.
|
||||
// If the function returns true then
|
||||
// v == (double) (buffer * 10^(decimal-point - length)).
|
||||
// The digits in the buffer are the shortest representation possible: no
|
||||
// 0.099999999999 instead of 0.1.
|
||||
// The last digit will be closest to the actual v. That is, even if several
|
||||
// digits might correctly yield 'v' when read again, the buffer will contain the
|
||||
// one closest to v.
|
||||
// The variable 'sign' will be '0' if the given number is positive, and '1'
|
||||
// otherwise.
|
||||
bool grisu3(double d, char* buffer, int* sign, int* length, int* decimal_point);
|
||||
|
||||
} } // namespace v8::internal
|
||||
|
||||
#endif // V8_GRISU3_H_
|
2461
src/powers_ten.h
Normal file
2461
src/powers_ten.h
Normal file
File diff suppressed because it is too large
Load Diff
@ -34,6 +34,7 @@ Import('context object_files')
|
||||
|
||||
SOURCES = {
|
||||
'all': [
|
||||
'gay_shortest.cc',
|
||||
'test-accessors.cc',
|
||||
'test-alloc.cc',
|
||||
'test-api.cc',
|
||||
@ -43,8 +44,11 @@ SOURCES = {
|
||||
'test-dataflow.cc',
|
||||
'test-debug.cc',
|
||||
'test-decls.cc',
|
||||
'test-diy_fp.cc',
|
||||
'test-double.cc',
|
||||
'test-flags.cc',
|
||||
'test-func-name-inference.cc',
|
||||
'test-grisu3.cc',
|
||||
'test-hashmap.cc',
|
||||
'test-heap.cc',
|
||||
'test-heap-profiler.cc',
|
||||
|
100048
test/cctest/gay_shortest.cc
Normal file
100048
test/cctest/gay_shortest.cc
Normal file
File diff suppressed because it is too large
Load Diff
44
test/cctest/gay_shortest.h
Normal file
44
test/cctest/gay_shortest.h
Normal file
@ -0,0 +1,44 @@
|
||||
// Copyright 2006-2008 the V8 project authors. All rights reserved.
|
||||
// Redistribution and use in source and binary forms, with or without
|
||||
// modification, are permitted provided that the following conditions are
|
||||
// met:
|
||||
//
|
||||
// * Redistributions of source code must retain the above copyright
|
||||
// notice, this list of conditions and the following disclaimer.
|
||||
// * Redistributions in binary form must reproduce the above
|
||||
// copyright notice, this list of conditions and the following
|
||||
// disclaimer in the documentation and/or other materials provided
|
||||
// with the distribution.
|
||||
// * Neither the name of Google Inc. nor the names of its
|
||||
// contributors may be used to endorse or promote products derived
|
||||
// from this software without specific prior written permission.
|
||||
//
|
||||
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
||||
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
||||
#ifndef GAY_SHORTEST_H_
|
||||
#define GAY_SHORTEST_H_
|
||||
|
||||
namespace v8 {
|
||||
namespace internal {
|
||||
|
||||
struct GayShortest {
|
||||
double v;
|
||||
const char* representation;
|
||||
int decimal_point;
|
||||
};
|
||||
|
||||
Vector<const GayShortest> PrecomputedShortestRepresentations();
|
||||
|
||||
} } // namespace v8::internal
|
||||
|
||||
#endif // GAY_SHORTEST_H_
|
67
test/cctest/test-diy_fp.cc
Normal file
67
test/cctest/test-diy_fp.cc
Normal file
@ -0,0 +1,67 @@
|
||||
// Copyright 2006-2008 the V8 project authors. All rights reserved.
|
||||
|
||||
#include <stdlib.h>
|
||||
|
||||
#include "v8.h"
|
||||
|
||||
#include "platform.h"
|
||||
#include "cctest.h"
|
||||
#include "diy_fp.h"
|
||||
|
||||
|
||||
using namespace v8::internal;
|
||||
|
||||
|
||||
TEST(Subtract) {
|
||||
DiyFp diy_fp1 = DiyFp(3, 0);
|
||||
DiyFp diy_fp2 = DiyFp(1, 0);
|
||||
DiyFp diff = DiyFp::Minus(diy_fp1, diy_fp2);
|
||||
|
||||
CHECK(2 == diff.f()); // NOLINT
|
||||
CHECK_EQ(0, diff.e());
|
||||
diy_fp1.Subtract(diy_fp2);
|
||||
CHECK(2 == diy_fp1.f()); // NOLINT
|
||||
CHECK_EQ(0, diy_fp1.e());
|
||||
}
|
||||
|
||||
|
||||
TEST(Multiply) {
|
||||
DiyFp diy_fp1 = DiyFp(3, 0);
|
||||
DiyFp diy_fp2 = DiyFp(2, 0);
|
||||
DiyFp product = DiyFp::Times(diy_fp1, diy_fp2);
|
||||
|
||||
CHECK(0 == product.f()); // NOLINT
|
||||
CHECK_EQ(64, product.e());
|
||||
diy_fp1.Multiply(diy_fp2);
|
||||
CHECK(0 == diy_fp1.f()); // NOLINT
|
||||
CHECK_EQ(64, diy_fp1.e());
|
||||
|
||||
diy_fp1 = DiyFp(V8_2PART_UINT64_C(0x80000000, 00000000), 11);
|
||||
diy_fp2 = DiyFp(2, 13);
|
||||
product = DiyFp::Times(diy_fp1, diy_fp2);
|
||||
CHECK(1 == product.f()); // NOLINT
|
||||
CHECK_EQ(11 + 13 + 64, product.e());
|
||||
|
||||
// Test rounding.
|
||||
diy_fp1 = DiyFp(V8_2PART_UINT64_C(0x80000000, 00000001), 11);
|
||||
diy_fp2 = DiyFp(1, 13);
|
||||
product = DiyFp::Times(diy_fp1, diy_fp2);
|
||||
CHECK(1 == product.f()); // NOLINT
|
||||
CHECK_EQ(11 + 13 + 64, product.e());
|
||||
|
||||
diy_fp1 = DiyFp(V8_2PART_UINT64_C(0x7fffffff, ffffffff), 11);
|
||||
diy_fp2 = DiyFp(1, 13);
|
||||
product = DiyFp::Times(diy_fp1, diy_fp2);
|
||||
CHECK(0 == product.f()); // NOLINT
|
||||
CHECK_EQ(11 + 13 + 64, product.e());
|
||||
|
||||
// Halfway cases are allowed to round either way. So don't check for it.
|
||||
|
||||
// Big numbers.
|
||||
diy_fp1 = DiyFp(V8_2PART_UINT64_C(0xFFFFFFFF, FFFFFFFF), 11);
|
||||
diy_fp2 = DiyFp(V8_2PART_UINT64_C(0xFFFFFFFF, FFFFFFFF), 13);
|
||||
// 128bit result: 0xfffffffffffffffe0000000000000001
|
||||
product = DiyFp::Times(diy_fp1, diy_fp2);
|
||||
CHECK(V8_2PART_UINT64_C(0xFFFFFFFF, FFFFFFFe) == product.f());
|
||||
CHECK_EQ(11 + 13 + 64, product.e());
|
||||
}
|
204
test/cctest/test-double.cc
Normal file
204
test/cctest/test-double.cc
Normal file
@ -0,0 +1,204 @@
|
||||
// Copyright 2006-2008 the V8 project authors. All rights reserved.
|
||||
|
||||
#include <stdlib.h>
|
||||
|
||||
#include "v8.h"
|
||||
|
||||
#include "platform.h"
|
||||
#include "cctest.h"
|
||||
#include "diy_fp.h"
|
||||
#include "double.h"
|
||||
|
||||
|
||||
using namespace v8::internal;
|
||||
|
||||
|
||||
TEST(Uint64Conversions) {
|
||||
// Start by checking the byte-order.
|
||||
uint64_t ordered = V8_2PART_UINT64_C(0x01234567, 89ABCDEF);
|
||||
CHECK_EQ(3512700564088504e-318, Double(ordered).value());
|
||||
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
CHECK_EQ(5e-324, Double(min_double64).value());
|
||||
|
||||
uint64_t max_double64 = V8_2PART_UINT64_C(0x7fefffff, ffffffff);
|
||||
CHECK_EQ(1.7976931348623157e308, Double(max_double64).value());
|
||||
}
|
||||
|
||||
TEST(AsDiyFp) {
|
||||
uint64_t ordered = V8_2PART_UINT64_C(0x01234567, 89ABCDEF);
|
||||
DiyFp diy_fp = Double(ordered).AsDiyFp();
|
||||
CHECK_EQ(0x12 - 0x3FF - 52, diy_fp.e());
|
||||
// The 52 mantissa bits, plus the implicit 1 in bit 52 as a UINT64.
|
||||
CHECK(V8_2PART_UINT64_C(0x00134567, 89ABCDEF) == diy_fp.f()); // NOLINT
|
||||
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
diy_fp = Double(min_double64).AsDiyFp();
|
||||
CHECK_EQ(-0x3FF - 52 + 1, diy_fp.e());
|
||||
// This is a denormal; so no hidden bit.
|
||||
CHECK(1 == diy_fp.f()); // NOLINT
|
||||
|
||||
uint64_t max_double64 = V8_2PART_UINT64_C(0x7fefffff, ffffffff);
|
||||
diy_fp = Double(max_double64).AsDiyFp();
|
||||
CHECK_EQ(0x7FE - 0x3FF - 52, diy_fp.e());
|
||||
CHECK(V8_2PART_UINT64_C(0x001fffff, ffffffff) == diy_fp.f()); // NOLINT
|
||||
}
|
||||
|
||||
|
||||
TEST(AsNormalizedDiyFp) {
|
||||
uint64_t ordered = V8_2PART_UINT64_C(0x01234567, 89ABCDEF);
|
||||
DiyFp diy_fp = Double(ordered).AsNormalizedDiyFp();
|
||||
CHECK_EQ(0x12 - 0x3FF - 52 - 11, diy_fp.e());
|
||||
CHECK((V8_2PART_UINT64_C(0x00134567, 89ABCDEF) << 11) ==
|
||||
diy_fp.f()); // NOLINT
|
||||
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
diy_fp = Double(min_double64).AsNormalizedDiyFp();
|
||||
CHECK_EQ(-0x3FF - 52 + 1 - 63, diy_fp.e());
|
||||
// This is a denormal; so no hidden bit.
|
||||
CHECK(V8_2PART_UINT64_C(0x80000000, 00000000) == diy_fp.f()); // NOLINT
|
||||
|
||||
uint64_t max_double64 = V8_2PART_UINT64_C(0x7fefffff, ffffffff);
|
||||
diy_fp = Double(max_double64).AsNormalizedDiyFp();
|
||||
CHECK_EQ(0x7FE - 0x3FF - 52 - 11, diy_fp.e());
|
||||
CHECK((V8_2PART_UINT64_C(0x001fffff, ffffffff) << 11) ==
|
||||
diy_fp.f()); // NOLINT
|
||||
}
|
||||
|
||||
|
||||
TEST(IsDenormal) {
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
CHECK(Double(min_double64).IsDenormal());
|
||||
uint64_t bits = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
|
||||
CHECK(Double(bits).IsDenormal());
|
||||
bits = V8_2PART_UINT64_C(0x00100000, 00000000);
|
||||
CHECK(!Double(bits).IsDenormal());
|
||||
}
|
||||
|
||||
|
||||
TEST(IsSpecial) {
|
||||
CHECK(Double(V8_INFINITY).IsSpecial());
|
||||
CHECK(Double(-V8_INFINITY).IsSpecial());
|
||||
CHECK(Double(OS::nan_value()).IsSpecial());
|
||||
uint64_t bits = V8_2PART_UINT64_C(0xFFF12345, 00000000);
|
||||
CHECK(Double(bits).IsSpecial());
|
||||
// Denormals are not special:
|
||||
CHECK(!Double(5e-324).IsSpecial());
|
||||
CHECK(!Double(-5e-324).IsSpecial());
|
||||
// And some random numbers:
|
||||
CHECK(!Double(0.0).IsSpecial());
|
||||
CHECK(!Double(-0.0).IsSpecial());
|
||||
CHECK(!Double(1.0).IsSpecial());
|
||||
CHECK(!Double(-1.0).IsSpecial());
|
||||
CHECK(!Double(1000000.0).IsSpecial());
|
||||
CHECK(!Double(-1000000.0).IsSpecial());
|
||||
CHECK(!Double(1e23).IsSpecial());
|
||||
CHECK(!Double(-1e23).IsSpecial());
|
||||
CHECK(!Double(1.7976931348623157e308).IsSpecial());
|
||||
CHECK(!Double(-1.7976931348623157e308).IsSpecial());
|
||||
}
|
||||
|
||||
|
||||
TEST(IsInfinite) {
|
||||
CHECK(Double(V8_INFINITY).IsInfinite());
|
||||
CHECK(Double(-V8_INFINITY).IsInfinite());
|
||||
CHECK(!Double(OS::nan_value()).IsInfinite());
|
||||
CHECK(!Double(0.0).IsInfinite());
|
||||
CHECK(!Double(-0.0).IsInfinite());
|
||||
CHECK(!Double(1.0).IsInfinite());
|
||||
CHECK(!Double(-1.0).IsInfinite());
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
CHECK(!Double(min_double64).IsInfinite());
|
||||
}
|
||||
|
||||
|
||||
TEST(IsNan) {
|
||||
CHECK(Double(OS::nan_value()).IsNan());
|
||||
uint64_t other_nan = V8_2PART_UINT64_C(0xFFFFFFFF, 00000001);
|
||||
CHECK(Double(other_nan).IsNan());
|
||||
CHECK(!Double(V8_INFINITY).IsNan());
|
||||
CHECK(!Double(-V8_INFINITY).IsNan());
|
||||
CHECK(!Double(0.0).IsNan());
|
||||
CHECK(!Double(-0.0).IsNan());
|
||||
CHECK(!Double(1.0).IsNan());
|
||||
CHECK(!Double(-1.0).IsNan());
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
CHECK(!Double(min_double64).IsNan());
|
||||
}
|
||||
|
||||
|
||||
TEST(Sign) {
|
||||
CHECK_EQ(1, Double(1.0).Sign());
|
||||
CHECK_EQ(1, Double(V8_INFINITY).Sign());
|
||||
CHECK_EQ(-1, Double(-V8_INFINITY).Sign());
|
||||
CHECK_EQ(1, Double(0.0).Sign());
|
||||
CHECK_EQ(-1, Double(-0.0).Sign());
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
CHECK_EQ(1, Double(min_double64).Sign());
|
||||
}
|
||||
|
||||
|
||||
TEST(NormalizedBoundaries) {
|
||||
DiyFp boundary_plus;
|
||||
DiyFp boundary_minus;
|
||||
DiyFp diy_fp = Double(1.5).AsNormalizedDiyFp();
|
||||
Double(1.5).NormalizedBoundaries(&boundary_minus, &boundary_plus);
|
||||
CHECK_EQ(diy_fp.e(), boundary_minus.e());
|
||||
CHECK_EQ(diy_fp.e(), boundary_plus.e());
|
||||
// 1.5 does not have a significand of the form 2^p (for some p).
|
||||
// Therefore its boundaries are at the same distance.
|
||||
CHECK(diy_fp.f() - boundary_minus.f() == boundary_plus.f() - diy_fp.f());
|
||||
CHECK((1 << 10) == diy_fp.f() - boundary_minus.f()); // NOLINT
|
||||
|
||||
diy_fp = Double(1.0).AsNormalizedDiyFp();
|
||||
Double(1.0).NormalizedBoundaries(&boundary_minus, &boundary_plus);
|
||||
CHECK_EQ(diy_fp.e(), boundary_minus.e());
|
||||
CHECK_EQ(diy_fp.e(), boundary_plus.e());
|
||||
// 1.0 does have a significand of the form 2^p (for some p).
|
||||
// Therefore its lower boundary is twice as close as the upper boundary.
|
||||
CHECK_GT(boundary_plus.f() - diy_fp.f(), diy_fp.f() - boundary_minus.f());
|
||||
CHECK((1 << 9) == diy_fp.f() - boundary_minus.f()); // NOLINT
|
||||
CHECK((1 << 10) == boundary_plus.f() - diy_fp.f()); // NOLINT
|
||||
|
||||
uint64_t min_double64 = V8_2PART_UINT64_C(0x00000000, 00000001);
|
||||
diy_fp = Double(min_double64).AsNormalizedDiyFp();
|
||||
Double(min_double64).NormalizedBoundaries(&boundary_minus, &boundary_plus);
|
||||
CHECK_EQ(diy_fp.e(), boundary_minus.e());
|
||||
CHECK_EQ(diy_fp.e(), boundary_plus.e());
|
||||
// min-value does not have a significand of the form 2^p (for some p).
|
||||
// Therefore its boundaries are at the same distance.
|
||||
CHECK(diy_fp.f() - boundary_minus.f() == boundary_plus.f() - diy_fp.f());
|
||||
// Denormals have their boundaries much closer.
|
||||
CHECK((static_cast<uint64_t>(1) << 62) ==
|
||||
diy_fp.f() - boundary_minus.f()); // NOLINT
|
||||
|
||||
uint64_t smallest_normal64 = V8_2PART_UINT64_C(0x00100000, 00000000);
|
||||
diy_fp = Double(smallest_normal64).AsNormalizedDiyFp();
|
||||
Double(smallest_normal64).NormalizedBoundaries(&boundary_minus,
|
||||
&boundary_plus);
|
||||
CHECK_EQ(diy_fp.e(), boundary_minus.e());
|
||||
CHECK_EQ(diy_fp.e(), boundary_plus.e());
|
||||
// Even though the significand is of the form 2^p (for some p), its boundaries
|
||||
// are at the same distance. (This is the only exception).
|
||||
CHECK(diy_fp.f() - boundary_minus.f() == boundary_plus.f() - diy_fp.f());
|
||||
CHECK((1 << 10) == diy_fp.f() - boundary_minus.f()); // NOLINT
|
||||
|
||||
uint64_t largest_denormal64 = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
|
||||
diy_fp = Double(largest_denormal64).AsNormalizedDiyFp();
|
||||
Double(largest_denormal64).NormalizedBoundaries(&boundary_minus,
|
||||
&boundary_plus);
|
||||
CHECK_EQ(diy_fp.e(), boundary_minus.e());
|
||||
CHECK_EQ(diy_fp.e(), boundary_plus.e());
|
||||
CHECK(diy_fp.f() - boundary_minus.f() == boundary_plus.f() - diy_fp.f());
|
||||
CHECK((1 << 11) == diy_fp.f() - boundary_minus.f()); // NOLINT
|
||||
|
||||
uint64_t max_double64 = V8_2PART_UINT64_C(0x7fefffff, ffffffff);
|
||||
diy_fp = Double(max_double64).AsNormalizedDiyFp();
|
||||
Double(max_double64).NormalizedBoundaries(&boundary_minus, &boundary_plus);
|
||||
CHECK_EQ(diy_fp.e(), boundary_minus.e());
|
||||
CHECK_EQ(diy_fp.e(), boundary_plus.e());
|
||||
// max-value does not have a significand of the form 2^p (for some p).
|
||||
// Therefore its boundaries are at the same distance.
|
||||
CHECK(diy_fp.f() - boundary_minus.f() == boundary_plus.f() - diy_fp.f());
|
||||
CHECK((1 << 10) == diy_fp.f() - boundary_minus.f()); // NOLINT
|
||||
}
|
116
test/cctest/test-grisu3.cc
Normal file
116
test/cctest/test-grisu3.cc
Normal file
@ -0,0 +1,116 @@
|
||||
// Copyright 2006-2008 the V8 project authors. All rights reserved.
|
||||
|
||||
#include <stdlib.h>
|
||||
|
||||
#include "v8.h"
|
||||
|
||||
#include "platform.h"
|
||||
#include "cctest.h"
|
||||
#include "diy_fp.h"
|
||||
#include "double.h"
|
||||
#include "gay_shortest.h"
|
||||
#include "grisu3.h"
|
||||
|
||||
using namespace v8::internal;
|
||||
|
||||
static const int kBufferSize = 100;
|
||||
|
||||
TEST(GrisuVariousDoubles) {
|
||||
char buffer[kBufferSize];
|
||||
int sign;
|
||||
int length;
|
||||
int point;
|
||||
int status;
|
||||
|
||||
double min_double = 5e-324;
|
||||
status = grisu3(min_double, buffer, &sign, &length, &point);
|
||||
CHECK(status);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("5", buffer);
|
||||
CHECK_EQ(-323, point);
|
||||
|
||||
double max_double = 1.7976931348623157e308;
|
||||
status = grisu3(max_double, buffer, &sign, &length, &point);
|
||||
CHECK(status);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("17976931348623157", buffer);
|
||||
CHECK_EQ(309, point);
|
||||
|
||||
status = grisu3(4294967272.0, buffer, &sign, &length, &point);
|
||||
CHECK(status);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("4294967272", buffer);
|
||||
CHECK_EQ(10, point);
|
||||
|
||||
status = grisu3(4.1855804968213567e298, buffer, &sign, &length, &point);
|
||||
CHECK(status);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("4185580496821357", buffer);
|
||||
CHECK_EQ(299, point);
|
||||
|
||||
status = grisu3(5.5626846462680035e-309, buffer, &sign, &length, &point);
|
||||
CHECK(status);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("5562684646268003", buffer);
|
||||
CHECK_EQ(-308, point);
|
||||
|
||||
status = grisu3(2147483648.0, buffer, &sign, &length, &point);
|
||||
CHECK(status);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("2147483648", buffer);
|
||||
CHECK_EQ(10, point);
|
||||
|
||||
status = grisu3(3.5844466002796428e+298, buffer, &sign, &length, &point);
|
||||
if (status) { // Not all grisu3 variants manage to compute this number.
|
||||
CHECK_EQ("35844466002796428", buffer);
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ(299, point);
|
||||
}
|
||||
|
||||
uint64_t smallest_normal64 = V8_2PART_UINT64_C(0x00100000, 00000000);
|
||||
double v = Double(smallest_normal64).value();
|
||||
status = grisu3(v, buffer, &sign, &length, &point);
|
||||
if (status) {
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("22250738585072014", buffer);
|
||||
CHECK_EQ(-307, point);
|
||||
}
|
||||
|
||||
uint64_t largest_denormal64 = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
|
||||
v = Double(largest_denormal64).value();
|
||||
status = grisu3(v, buffer, &sign, &length, &point);
|
||||
if (status) {
|
||||
CHECK_EQ(0, sign);
|
||||
CHECK_EQ("2225073858507201", buffer);
|
||||
CHECK_EQ(-307, point);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
TEST(GrisuGayShortest) {
|
||||
char buffer[kBufferSize];
|
||||
bool status;
|
||||
int sign;
|
||||
int length;
|
||||
int point;
|
||||
int succeeded = 0;
|
||||
int total = 0;
|
||||
bool needed_max_length = false;
|
||||
|
||||
Vector<const GayShortest> precomputed = PrecomputedShortestRepresentations();
|
||||
for (int i = 0; i < precomputed.length(); ++i) {
|
||||
const GayShortest current_test = precomputed[i];
|
||||
total++;
|
||||
double v = current_test.v;
|
||||
status = grisu3(v, buffer, &sign, &length, &point);
|
||||
CHECK_GE(kGrisu3MaximalLength, length);
|
||||
if (!status) continue;
|
||||
if (length == kGrisu3MaximalLength) needed_max_length = true;
|
||||
succeeded++;
|
||||
CHECK_EQ(0, sign); // All precomputed numbers are positive.
|
||||
CHECK_EQ(current_test.decimal_point, point);
|
||||
CHECK_EQ(current_test.representation, buffer);
|
||||
}
|
||||
CHECK_GT(succeeded*1.0/total, 0.99);
|
||||
CHECK(needed_max_length);
|
||||
}
|
286
tools/generate-ten-powers.scm
Normal file
286
tools/generate-ten-powers.scm
Normal file
@ -0,0 +1,286 @@
|
||||
;; Copyright 2010 the V8 project authors. All rights reserved.
|
||||
;; Redistribution and use in source and binary forms, with or without
|
||||
;; modification, are permitted provided that the following conditions are
|
||||
;; met:
|
||||
;;
|
||||
;; * Redistributions of source code must retain the above copyright
|
||||
;; notice, this list of conditions and the following disclaimer.
|
||||
;; * Redistributions in binary form must reproduce the above
|
||||
;; copyright notice, this list of conditions and the following
|
||||
;; disclaimer in the documentation and/or other materials provided
|
||||
;; with the distribution.
|
||||
;; * Neither the name of Google Inc. nor the names of its
|
||||
;; contributors may be used to endorse or promote products derived
|
||||
;; from this software without specific prior written permission.
|
||||
;;
|
||||
;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
||||
;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
||||
;; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||||
;; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
||||
;; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
;; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
;; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
|
||||
;; This is a Scheme script for the Bigloo compiler. Bigloo must be compiled with
|
||||
;; support for bignums. The compilation of the script can be done as follows:
|
||||
;; bigloo -static-bigloo -o generate-ten-powers generate-ten-powers.scm
|
||||
;;
|
||||
;; Generate approximations of 10^k.
|
||||
|
||||
(module gen-ten-powers
|
||||
(static (class Cached-Fast
|
||||
v::bignum
|
||||
e::bint
|
||||
exact?::bool))
|
||||
(main my-main))
|
||||
|
||||
|
||||
;;----------------bignum shifts -----------------------------------------------
|
||||
(define (bit-lshbx::bignum x::bignum by::bint)
|
||||
(if (<fx by 0)
|
||||
#z0
|
||||
(*bx x (exptbx #z2 (fixnum->bignum by)))))
|
||||
|
||||
(define (bit-rshbx::bignum x::bignum by::bint)
|
||||
(if (<fx by 0)
|
||||
#z0
|
||||
(/bx x (exptbx #z2 (fixnum->bignum by)))))
|
||||
|
||||
;;----------------the actual power generation -------------------------------
|
||||
|
||||
;; e should be an indication. it might be too small.
|
||||
(define (round-n-cut n e nb-bits)
|
||||
(define max-container (- (bit-lshbx #z1 nb-bits) 1))
|
||||
(define (round n)
|
||||
(case *round*
|
||||
((down) n)
|
||||
((up)
|
||||
(+bx n
|
||||
;; with the -1 it will only round up if the cut off part is
|
||||
;; non-zero
|
||||
(-bx (bit-lshbx #z1
|
||||
(-fx (+fx e nb-bits) 1))
|
||||
#z1)))
|
||||
((round)
|
||||
(+bx n
|
||||
(bit-lshbx #z1
|
||||
(-fx (+fx e nb-bits) 2))))))
|
||||
(let* ((shift (-fx (+fx e nb-bits) 1))
|
||||
(cut (bit-rshbx (round n) shift))
|
||||
(exact? (=bx n (bit-lshbx cut shift))))
|
||||
(if (<=bx cut max-container)
|
||||
(values cut e exact?)
|
||||
(round-n-cut n (+fx e 1) nb-bits))))
|
||||
|
||||
(define (rounded-/bx x y)
|
||||
(case *round*
|
||||
((down) (/bx x y))
|
||||
((up) (+bx (/bx x y) #z1))
|
||||
((round) (let ((tmp (/bx (*bx #z2 x) y)))
|
||||
(if (zerobx? (remainderbx tmp #z2))
|
||||
(/bx tmp #z2)
|
||||
(+bx (/bx tmp #z2) #z1))))))
|
||||
|
||||
(define (generate-powers from to mantissa-size)
|
||||
(let* ((nb-bits mantissa-size)
|
||||
(offset (- from))
|
||||
(nb-elements (+ (- from) to 1))
|
||||
(vec (make-vector nb-elements))
|
||||
(max-container (- (bit-lshbx #z1 nb-bits) 1)))
|
||||
;; the negative ones. 10^-1, 10^-2, etc.
|
||||
;; We already know, that we can't be exact, so exact? will always be #f.
|
||||
;; Basically we will have a ten^i that we will *10 at each iteration. We
|
||||
;; want to create the matissa of 1/ten^i. However the mantissa must be
|
||||
;; normalized (start with a 1). -> we have to shift the number.
|
||||
;; We shift by multiplying with two^e. -> We encode two^e*(1/ten^i) ==
|
||||
;; two^e/ten^i.
|
||||
(let loop ((i 1)
|
||||
(ten^i #z10)
|
||||
(two^e #z1)
|
||||
(e 0))
|
||||
(unless (< (- i) from)
|
||||
(if (>bx (/bx (*bx #z2 two^e) ten^i) max-container)
|
||||
;; another shift would make the number too big. We are
|
||||
;; hence normalized now.
|
||||
(begin
|
||||
(vector-set! vec (-fx offset i)
|
||||
(instantiate::Cached-Fast
|
||||
(v (rounded-/bx two^e ten^i))
|
||||
(e (negfx e))
|
||||
(exact? #f)))
|
||||
(loop (+fx i 1) (*bx ten^i #z10) two^e e))
|
||||
(loop i ten^i (bit-lshbx two^e 1) (+fx e 1)))))
|
||||
;; the positive ones 10^0, 10^1, etc.
|
||||
;; start with 1.0. mantissa: 10...0 (1 followed by nb-bits-1 bits)
|
||||
;; -> e = -(nb-bits-1)
|
||||
;; exact? is true when the container can still hold the complete 10^i
|
||||
(let loop ((i 0)
|
||||
(n (bit-lshbx #z1 (-fx nb-bits 1)))
|
||||
(e (-fx 1 nb-bits)))
|
||||
(when (<= i to)
|
||||
(receive (cut e exact?)
|
||||
(round-n-cut n e nb-bits)
|
||||
(vector-set! vec (+fx i offset)
|
||||
(instantiate::Cached-Fast
|
||||
(v cut)
|
||||
(e e)
|
||||
(exact? exact?)))
|
||||
(loop (+fx i 1) (*bx n #z10) e))))
|
||||
vec))
|
||||
|
||||
(define (print-c powers from to struct-type
|
||||
cache-name max-distance-name offset-name macro64)
|
||||
(define (display-power power k)
|
||||
(with-access::Cached-Fast power (v e exact?)
|
||||
(let ((tmp-p (open-output-string)))
|
||||
;; really hackish way of getting the digits
|
||||
(display (format "~x" v) tmp-p)
|
||||
(let ((str (close-output-port tmp-p)))
|
||||
(printf " {~a(0x~a, ~a), ~a, ~a},\n"
|
||||
macro64
|
||||
(substring str 0 8)
|
||||
(substring str 8 16)
|
||||
e
|
||||
k)))))
|
||||
(define (print-powers-reduced n)
|
||||
(print "static const " struct-type " " cache-name
|
||||
"(" n ")"
|
||||
"[] = {")
|
||||
(let loop ((i 0)
|
||||
(nb-elements 0)
|
||||
(last-e 0)
|
||||
(max-distance 0))
|
||||
(cond
|
||||
((>= i (vector-length powers))
|
||||
(print " };")
|
||||
(print "static const int " max-distance-name "(" n ") = "
|
||||
max-distance ";")
|
||||
(print "// nb elements (" n "): " nb-elements))
|
||||
(else
|
||||
(let* ((power (vector-ref powers i))
|
||||
(e (Cached-Fast-e power)))
|
||||
(display-power power (+ i from))
|
||||
(loop (+ i n)
|
||||
(+ nb-elements 1)
|
||||
e
|
||||
(cond
|
||||
((=fx i 0) max-distance)
|
||||
((> (- e last-e) max-distance) (- e last-e))
|
||||
(else max-distance))))))))
|
||||
(print "// Copyright 2010 the V8 project authors. All rights reserved.")
|
||||
(print "// ------------ GENERATED FILE ----------------")
|
||||
(print "// command used:")
|
||||
(print "// "
|
||||
(apply string-append (map (lambda (str)
|
||||
(string-append " " str))
|
||||
*main-args*))
|
||||
" // NOLINT")
|
||||
(print)
|
||||
(print
|
||||
"// This file is intended to be included inside another .h or .cc files\n"
|
||||
"// with the following defines set:\n"
|
||||
"// GRISU_CACHE_STRUCT: should expand to the name of a struct that will\n"
|
||||
"// hold the cached powers of ten. Each entry will hold a 64-bit\n"
|
||||
"// significand, a 16-bit signed binary exponent, and a 16-bit\n"
|
||||
"// signed decimal exponent. Each entry will be constructed as follows:\n"
|
||||
"// { significand, binary_exponent, decimal_exponent }.\n"
|
||||
"// GRISU_CACHE_NAME(i): generates the name for the different caches.\n"
|
||||
"// The parameter i will be a number in the range 1-20. A cache will\n"
|
||||
"// hold every i'th element of a full cache. GRISU_CACHE_NAME(1) will\n"
|
||||
"// thus hold all elements. The higher i the fewer elements it has.\n"
|
||||
"// Ideally the user should only reference one cache and let the\n"
|
||||
"// compiler remove the unused ones.\n"
|
||||
"// GRISU_CACHE_MAX_DISTANCE(i): generates the name for the maximum\n"
|
||||
"// binary exponent distance between all elements of a given cache.\n"
|
||||
"// GRISU_CACHE_OFFSET: is used as variable name for the decimal\n"
|
||||
"// exponent offset. It is equal to -cache[0].decimal_exponent.\n"
|
||||
"// GRISU_UINT64_C: used to construct 64-bit values in a platform\n"
|
||||
"// independent way. In order to encode 0x123456789ABCDEF0 the macro\n"
|
||||
"// will be invoked as follows: GRISU_UINT64_C(0x12345678,9ABCDEF0).\n")
|
||||
(print)
|
||||
(print-powers-reduced 1)
|
||||
(print-powers-reduced 2)
|
||||
(print-powers-reduced 3)
|
||||
(print-powers-reduced 4)
|
||||
(print-powers-reduced 5)
|
||||
(print-powers-reduced 6)
|
||||
(print-powers-reduced 7)
|
||||
(print-powers-reduced 8)
|
||||
(print-powers-reduced 9)
|
||||
(print-powers-reduced 10)
|
||||
(print-powers-reduced 11)
|
||||
(print-powers-reduced 12)
|
||||
(print-powers-reduced 13)
|
||||
(print-powers-reduced 14)
|
||||
(print-powers-reduced 15)
|
||||
(print-powers-reduced 16)
|
||||
(print-powers-reduced 17)
|
||||
(print-powers-reduced 18)
|
||||
(print-powers-reduced 19)
|
||||
(print-powers-reduced 20)
|
||||
(print "static const int GRISU_CACHE_OFFSET = " (- from) ";"))
|
||||
|
||||
;;----------------main --------------------------------------------------------
|
||||
(define *main-args* #f)
|
||||
(define *mantissa-size* #f)
|
||||
(define *dest* #f)
|
||||
(define *round* #f)
|
||||
(define *from* #f)
|
||||
(define *to* #f)
|
||||
|
||||
(define (my-main args)
|
||||
(set! *main-args* args)
|
||||
(args-parse (cdr args)
|
||||
(section "Help")
|
||||
(("?") (args-parse-usage #f))
|
||||
((("-h" "--help") (help "?, -h, --help" "This help message"))
|
||||
(args-parse-usage #f))
|
||||
(section "Misc")
|
||||
(("-o" ?file (help "The output file"))
|
||||
(set! *dest* file))
|
||||
(("--mantissa-size" ?size (help "Container-size in bits"))
|
||||
(set! *mantissa-size* (string->number size)))
|
||||
(("--round" ?direction (help "Round bignums (down, round or up)"))
|
||||
(set! *round* (string->symbol direction)))
|
||||
(("--from" ?from (help "start at 10^from"))
|
||||
(set! *from* (string->number from)))
|
||||
(("--to" ?to (help "go up to 10^to"))
|
||||
(set! *to* (string->number to)))
|
||||
(else
|
||||
(print "Illegal argument `" else "'. Usage:")
|
||||
(args-parse-usage #f)))
|
||||
(when (not *from*)
|
||||
(error "generate-ten-powers"
|
||||
"Missing from"
|
||||
#f))
|
||||
(when (not *to*)
|
||||
(error "generate-ten-powers"
|
||||
"Missing to"
|
||||
#f))
|
||||
(when (not *mantissa-size*)
|
||||
(error "generate-ten-powers"
|
||||
"Missing mantissa size"
|
||||
#f))
|
||||
(when (not (memv *round* '(up down round)))
|
||||
(error "generate-ten-powers"
|
||||
"Missing round-method"
|
||||
*round*))
|
||||
|
||||
(let ((dividers (generate-powers *from* *to* *mantissa-size*))
|
||||
(p (if (not *dest*)
|
||||
(current-output-port)
|
||||
(open-output-file *dest*))))
|
||||
(unwind-protect
|
||||
(with-output-to-port p
|
||||
(lambda ()
|
||||
(print-c dividers *from* *to*
|
||||
"GRISU_CACHE_STRUCT" "GRISU_CACHE_NAME"
|
||||
"GRISU_CACHE_MAX_DISTANCE" "GRISU_CACHE_OFFSET"
|
||||
"GRISU_UINT64_C"
|
||||
)))
|
||||
(if *dest*
|
||||
(close-output-port p)))))
|
@ -229,6 +229,7 @@
|
||||
'../../src/builtins.cc',
|
||||
'../../src/builtins.h',
|
||||
'../../src/bytecodes-irregexp.h',
|
||||
'../../src/cached_powers.h',
|
||||
'../../src/char-predicates-inl.h',
|
||||
'../../src/char-predicates.h',
|
||||
'../../src/checks.cc',
|
||||
@ -264,6 +265,8 @@
|
||||
'../../src/disassembler.cc',
|
||||
'../../src/disassembler.h',
|
||||
'../../src/dtoa-config.c',
|
||||
'../../src/diy_fp.h',
|
||||
'../../src/double.h',
|
||||
'../../src/execution.cc',
|
||||
'../../src/execution.h',
|
||||
'../../src/factory.cc',
|
||||
@ -284,6 +287,8 @@
|
||||
'../../src/global-handles.cc',
|
||||
'../../src/global-handles.h',
|
||||
'../../src/globals.h',
|
||||
'../../src/grisu3.h',
|
||||
'../../src/grisu3.cc',
|
||||
'../../src/handles-inl.h',
|
||||
'../../src/handles.cc',
|
||||
'../../src/handles.h',
|
||||
@ -330,6 +335,7 @@
|
||||
'../../src/parser.cc',
|
||||
'../../src/parser.h',
|
||||
'../../src/platform.h',
|
||||
'../../src/powers_ten.h',
|
||||
'../../src/prettyprinter.cc',
|
||||
'../../src/prettyprinter.h',
|
||||
'../../src/property.cc',
|
||||
|
Loading…
Reference in New Issue
Block a user