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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
282 lines
8.1 KiB
ArmAsm
282 lines
8.1 KiB
ArmAsm
.file "logb.s"
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// Copyright (c) 2000 - 2003, Intel Corporation
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// All rights reserved.
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//
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//
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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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//
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// * Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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//
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// * The name of Intel Corporation may not be used to endorse or promote
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// products derived from this software without specific prior written
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// permission.
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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 INTEL OR ITS
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// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// Intel Corporation is the author of this code, and requests that all
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// problem reports or change requests be submitted to it directly at
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// http://www.intel.com/software/products/opensource/libraries/num.htm.
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//
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// History
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//==============================================================
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// 02/02/00 Initial version
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// 02/16/00 Modified to conform to C9X
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// 03/16/00 Improved speed
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// 04/04/00 Unwind support added
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// 05/30/00 Fixed bug when x double-extended denormal
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// 08/15/00 Bundle added after call to __libm_error_support to properly
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// set [the previously overwritten] GR_Parameter_RESULT.
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// 05/20/02 Cleaned up namespace and sf0 syntax
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// 01/20/03 Improved performance
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//
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// API
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//==============================================================
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// double logb( double x );
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//
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// Overview of operation
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//==============================================================
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// The logb function extracts the exponent of x as an integer in
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// floating-point format.
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// logb computes log2 of x as a double
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//
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// logb is similar to ilogb but differs in the following ways:
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// +-inf
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// ilogb: returns INT_MAX
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// logb: returns +inf
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// Nan returns FP_LOGBNAN (which is either INT_MAX or INT_MIN)
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// ilogb: returns INT_MAX (7fffffff)
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// logb: returns QNAN (quietized SNAN)
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// 0 returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX)
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// ilogb: returns -INT_MAX (80000001)
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// logb: returns -inf, raises the divide-by-zero exception,
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// and calls libm_error_support to set domain error
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//
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// Registers used
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//==============================================================
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// general registers used:
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// r26 -> r38
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// r35 -> r38 used as parameters to error path
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//
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// predicate registers used:
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// p6, p7, p8
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// floating-point registers used:
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// f9, f10, f11
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// f8, input
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rExpBias = r26
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rExpMask = r27
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rSignexp_x = r28
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rExp_x = r29
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rTrueExp_x = r30
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rExp_2to64 = r31
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GR_SAVE_PFS = r32
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GR_SAVE_B0 = r33
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GR_SAVE_GP = r34
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GR_Parameter_X = r35
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GR_Parameter_Y = r36
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GR_Parameter_RESULT = r37
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GR_Parameter_TAG = r38
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fExp_in_signif = f9
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fNorm_x = f10
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fFloat_Exp = f10
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f2to64 = f11
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.section .text
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GLOBAL_LIBM_ENTRY(logb)
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// X NORMAL
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// TrueExp_x = exp(f8) - 0xffff
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// sig = TrueExp_x
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// f8 = convert_to_fp (sig))
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{ .mfi
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getf.exp rSignexp_x = f8
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fclass.m p8,p0 = f8, 0x0b // Test for x unorm
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mov rExpBias = 0xffff // Exponent bias
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}
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{ .mfi
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nop.m 0
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fnorm.s1 fNorm_x = f8
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mov rExpMask = 0x1ffff // Exponent mask
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}
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;;
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// Form signexp of 2^64 in case need to scale denormal
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{ .mfb
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mov rExp_2to64 = 0x1003f
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fclass.m p6,p0 = f8, 0x1e3 // Test x natval, nan, inf
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(p8) br.cond.spnt LOGB_DENORM // Branch if x unorm
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}
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;;
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LOGB_COMMON:
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// Return here from LOGB_DENORM
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{ .mfi
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and rExp_x = rSignexp_x, rExpMask // Get biased exponent
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fclass.m p7,p0 = f8, 0x07 // Test x zero
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nop.i 0
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}
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;;
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// X NAN or INFINITY, return f8 * f8
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{ .mfb
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sub rTrueExp_x = rExp_x, rExpBias // Get true exponent
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(p6) fma.d.s0 f8= f8,f8,f0 // Result if x natval, nan, inf
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(p6) br.ret.spnt b0 // Exit if x natval, nan, inf
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}
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;;
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{ .mib
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setf.sig fExp_in_signif = rTrueExp_x // Exponent as integer in fp
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nop.i 999
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(p7) br.cond.spnt LOGB_ZERO
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}
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;;
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// Result can be represented in less than 24 bits, so no precision completer
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// is needed.
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{ .mfb
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nop.m 0
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fcvt.xf f8 = fExp_in_signif
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br.ret.sptk b0 // Exit main path, 0 < |x| < inf
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}
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;;
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LOGB_DENORM:
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// Form 2^64 in case need to scale denormal
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// Check to see if double-extended denormal
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{ .mfi
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setf.exp f2to64 = rExp_2to64
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fclass.m p8,p0 = fNorm_x, 0x0b
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nop.i 0
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}
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;;
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{ .mfi
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nop.m 0
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fcmp.eq.s0 p7,p0 = f8, f0 // Dummy op to set denormal flag
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nop.i 0
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}
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;;
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// If double-extended denormal add 64 to exponent bias for scaling
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// If double-extended denormal form x * 2^64 which is normal
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{ .mfi
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(p8) add rExpBias = 64, rExpBias
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(p8) fmpy.s1 fNorm_x = fNorm_x, f2to64
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nop.i 0
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}
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;;
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// Logic is the same as normal path but use normalized input
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{ .mib
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getf.exp rSignexp_x = fNorm_x
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nop.i 0
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br.cond.sptk LOGB_COMMON // Return to main path
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}
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;;
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LOGB_ZERO:
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// Here if x zero
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// f10 = -|f8|
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// f9 = 1.0/f10 = -1.0/|f8| = -inf
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{ .mmf
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alloc r32=ar.pfs,1,2,4,0
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mov GR_Parameter_TAG = 151 // Error code
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fmerge.ns f10 = f0,f8
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}
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;;
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{ .mfb
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nop.m 0
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frcpa.s0 f9,p6 = f1,f10 // Produce -inf, Z flag
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br.cond.sptk __libm_error_region // Call error support
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}
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;;
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GLOBAL_LIBM_END(logb)
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libm_alias_double_other (logb, logb)
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LOCAL_LIBM_ENTRY(__libm_error_region)
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.prologue
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{ .mfi
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add GR_Parameter_Y=-32,sp // Parameter 2 value
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nop.f 0
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.save ar.pfs,GR_SAVE_PFS
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mov GR_SAVE_PFS=ar.pfs // Save ar.pfs
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}
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{ .mfi
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.fframe 64
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add sp=-64,sp // Create new stack
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nop.f 0
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mov GR_SAVE_GP=gp // Save gp
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};;
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{ .mmi
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stfd [GR_Parameter_Y] = f0,16 // STORE Parameter 2 on stack
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add GR_Parameter_X = 16,sp // Parameter 1 address
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.save b0, GR_SAVE_B0
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mov GR_SAVE_B0=b0 // Save b0
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};;
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.body
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{ .mib
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stfd [GR_Parameter_X] = f8 // STORE Parameter 1 on stack
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add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address
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nop.b 0
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}
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{ .mib
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stfd [GR_Parameter_Y] = f9 // Store Parameter 3 on stack
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add GR_Parameter_Y = -16,GR_Parameter_Y
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br.call.sptk b0=__libm_error_support# // Call error handling function
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};;
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{ .mmi
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add GR_Parameter_RESULT = 48,sp
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nop.m 0
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nop.i 0
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};;
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{ .mmi
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ldfd f8 = [GR_Parameter_RESULT] // Get return result off stack
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.restore sp
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add sp = 64,sp // Restore stack pointer
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mov b0 = GR_SAVE_B0 // Restore return address
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};;
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{ .mib
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mov gp = GR_SAVE_GP // Restore gp
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mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs
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br.ret.sptk b0
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};;
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LOCAL_LIBM_END(__libm_error_region)
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.type __libm_error_support#,@function
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.global __libm_error_support#
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