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453 lines
11 KiB
ArmAsm
453 lines
11 KiB
ArmAsm
.file "libm_scalbnl.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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// Contributed 2000 by the Intel Numerics Group, Intel Corporation
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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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// 01/26/01 Scalbnl completely reworked and now standalone version
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// 01/04/02 Added handling for int 32 or 64 bits
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// 05/20/02 Cleaned up namespace and sf0 syntax
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// 02/10/03 Reordered header: .section, .global, .proc, .align
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// 08/04/03 Improved performance
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//
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// API
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//==============================================================
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// long double __libm_scalbnl (long double x, int n, int int_type)
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// input floating point f8 and int n (r34), int int_type (r35)
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// output floating point f8
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//
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// int_type = 0 if int is 32 bits
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// int_type = 1 if int is 64 bits
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//
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// Returns x* 2**n using an fma and detects overflow
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// and underflow.
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//
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//
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// Strategy:
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// Compute biased exponent of result exp_Result = N + exp_X
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// Break into ranges:
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// exp_Result > 0x13ffe -> Certain overflow
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// exp_Result = 0x13ffe -> Possible overflow
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// 0x0c001 <= exp_Result < 0x13ffe -> No over/underflow (main path)
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// 0x0c001 - 63 <= exp_Result < 0x0c001 -> Possible underflow
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// exp_Result < 0x0c001 - 63 -> Certain underflow
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FR_Big = f6
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FR_NBig = f7
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FR_Floating_X = f8
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FR_Result = f8
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FR_Result2 = f9
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FR_Result3 = f10
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FR_Norm_X = f11
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FR_Two_N = f12
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GR_neg_ov_limit= r14
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GR_N_Biased = r15
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GR_Big = r16
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GR_NBig = r17
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GR_exp_Result = r18
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GR_pos_ov_limit= r19
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GR_Bias = r20
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GR_N_as_int = r21
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GR_signexp_X = r22
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GR_exp_X = r23
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GR_exp_mask = r24
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GR_max_exp = r25
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GR_min_exp = r26
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GR_min_den_exp = r27
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GR_SAVE_B0 = r32
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GR_SAVE_GP = r33
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GR_SAVE_PFS = 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_Tag = r38
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.section .text
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GLOBAL_LIBM_ENTRY(__libm_scalbnl)
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//
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// Is x NAN, INF, ZERO, +-?
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// Build the exponent Bias
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//
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{ .mfi
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getf.exp GR_signexp_X = FR_Floating_X // Get signexp of x
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fclass.m p6,p0 = FR_Floating_X, 0xe7 // @snan | @qnan | @inf | @zero
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mov GR_Bias = 0x0ffff
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}
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//
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// Normalize x
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// Is integer type 32 bits?
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//
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{ .mfi
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mov GR_Big = 35000 // If N this big then certain overflow
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fnorm.s1 FR_Norm_X = FR_Floating_X
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cmp.eq p8,p9 = r35,r0
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}
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;;
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// Sign extend N if int is 32 bits
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{ .mfi
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(p9) mov GR_N_as_int = r34 // Copy N if int is 64 bits
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fclass.m p9,p0 = FR_Floating_X, 0x0b // Test for x=unorm
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(p8) sxt4 GR_N_as_int = r34 // Sign extend N if int is 32 bits
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}
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{ .mfi
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mov GR_NBig = -35000 // If N this small then certain underflow
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nop.f 0
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mov GR_max_exp = 0x13ffe // Exponent of maximum long double
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}
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;;
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// Create biased exponent for 2**N
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{ .mfi
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add GR_N_Biased = GR_Bias,GR_N_as_int
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nop.f 0
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cmp.ge p7, p0 = GR_N_as_int, GR_Big // Certain overflow?
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}
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{ .mib
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cmp.le p8, p0 = GR_N_as_int, GR_NBig // Certain underflow?
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mov GR_min_exp = 0x0c001 // Exponent of minimum long double
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(p9) br.cond.spnt SCALBNL_UNORM // Branch if x=unorm
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}
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;;
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SCALBNL_COMMON:
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// Main path continues. Also return here from x=unorm path.
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// Create 2**N
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.pred.rel "mutex",p7,p8
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{ .mfi
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setf.exp FR_Two_N = GR_N_Biased
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nop.f 0
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(p7) mov GR_N_as_int = GR_Big // Limit max N
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}
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{ .mfi
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(p8) mov GR_N_as_int = GR_NBig // Limit min N
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nop.f 0
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(p8) cmp.eq p7,p0 = r0,r0 // Set p7 if |N| big
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}
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;;
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//
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// Create biased exponent for 2**N for N big
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// Is N zero?
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//
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{ .mfi
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(p7) add GR_N_Biased = GR_Bias,GR_N_as_int
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nop.f 0
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cmp.eq.or p6,p0 = r34,r0
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}
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{ .mfi
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mov GR_pos_ov_limit = 0x13fff // Exponent for positive overflow
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nop.f 0
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mov GR_exp_mask = 0x1ffff // Exponent mask
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}
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;;
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//
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// Create 2**N for N big
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// Return x when N = 0 or X = Nan, Inf, Zero
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//
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{ .mfi
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(p7) setf.exp FR_Two_N = GR_N_Biased
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nop.f 0
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mov GR_min_den_exp = 0x0c001 - 63 // Exp of min denorm long dble
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}
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{ .mfb
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and GR_exp_X = GR_exp_mask, GR_signexp_X
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(p6) fma.s0 FR_Result = FR_Floating_X, f1, f0
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(p6) br.ret.spnt b0
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}
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;;
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//
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// Raise Denormal operand flag with compare
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// Compute biased result exponent
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//
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{ .mfi
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add GR_exp_Result = GR_exp_X, GR_N_as_int
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fcmp.ge.s0 p0,p11 = FR_Floating_X,f0
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mov GR_neg_ov_limit = 0x33fff // Exponent for negative overflow
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}
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;;
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//
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// Do final operation
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//
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{ .mfi
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cmp.lt p7,p6 = GR_exp_Result, GR_max_exp // Test no overflow
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fma.s0 FR_Result = FR_Two_N,FR_Norm_X,f0
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cmp.lt p9,p0 = GR_exp_Result, GR_min_den_exp // Test sure underflow
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}
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{ .mfb
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nop.m 0
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nop.f 0
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(p9) br.cond.spnt SCALBNL_UNDERFLOW // Branch if certain underflow
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}
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;;
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{ .mib
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(p6) cmp.gt.unc p6,p8 = GR_exp_Result, GR_max_exp // Test sure overflow
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(p7) cmp.ge.unc p7,p9 = GR_exp_Result, GR_min_exp // Test no over/underflow
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(p7) br.ret.sptk b0 // Return from main path
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}
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;;
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{ .bbb
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(p6) br.cond.spnt SCALBNL_OVERFLOW // Branch if certain overflow
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(p8) br.cond.spnt SCALBNL_POSSIBLE_OVERFLOW // Branch if possible overflow
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(p9) br.cond.spnt SCALBNL_POSSIBLE_UNDERFLOW // Branch if possible underflow
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}
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;;
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// Here if possible underflow.
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// Resulting exponent: 0x0c001-63 <= exp_Result < 0x0c001
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SCALBNL_POSSIBLE_UNDERFLOW:
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//
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// Here if possible overflow.
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// Resulting exponent: 0x13ffe = exp_Result
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SCALBNL_POSSIBLE_OVERFLOW:
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// Set up necessary status fields
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//
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// S0 user supplied status
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// S2 user supplied status + WRE + TD (Overflows)
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// S3 user supplied status + FZ + TD (Underflows)
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//
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{ .mfi
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nop.m 0
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fsetc.s3 0x7F,0x41
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nop.i 0
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}
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{ .mfi
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nop.m 0
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fsetc.s2 0x7F,0x42
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nop.i 0
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}
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;;
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//
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// Do final operation with s2 and s3
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//
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{ .mfi
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setf.exp FR_NBig = GR_neg_ov_limit
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fma.s3 FR_Result3 = FR_Two_N,FR_Norm_X,f0
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nop.i 0
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}
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{ .mfi
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setf.exp FR_Big = GR_pos_ov_limit
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fma.s2 FR_Result2 = FR_Two_N,FR_Norm_X,f0
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nop.i 0
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}
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;;
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// Check for overflow or underflow.
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// Restore s3
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// Restore s2
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//
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{ .mfi
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nop.m 0
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fsetc.s3 0x7F,0x40
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nop.i 0
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}
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{ .mfi
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nop.m 0
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fsetc.s2 0x7F,0x40
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nop.i 0
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}
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;;
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//
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// Is the result zero?
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//
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{ .mfi
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nop.m 0
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fclass.m p6, p0 = FR_Result3, 0x007
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nop.i 0
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}
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{ .mfi
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nop.m 0
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fcmp.ge.s1 p7, p8 = FR_Result2 , FR_Big
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nop.i 0
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}
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;;
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//
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// Detect masked underflow - Tiny + Inexact Only
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//
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{ .mfi
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nop.m 0
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(p6) fcmp.neq.unc.s1 p6, p0 = FR_Result , FR_Result2
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nop.i 0
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}
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;;
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//
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// Is result bigger the allowed range?
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// Branch out for underflow
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//
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{ .mfb
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nop.m 0
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(p8) fcmp.le.unc.s1 p9, p10 = FR_Result2 , FR_NBig
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(p6) br.cond.spnt SCALBNL_UNDERFLOW
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}
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;;
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//
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// Branch out for overflow
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//
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{ .bbb
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(p7) br.cond.spnt SCALBNL_OVERFLOW
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(p9) br.cond.spnt SCALBNL_OVERFLOW
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br.ret.sptk b0 // Return from main path.
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}
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;;
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// Here if result overflows
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SCALBNL_OVERFLOW:
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{ .mib
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alloc r32=ar.pfs,3,0,4,0
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addl GR_Tag = 174, r0 // Set error tag for overflow
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br.cond.sptk __libm_error_region // Call error support for overflow
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}
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;;
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// Here if result underflows
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SCALBNL_UNDERFLOW:
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{ .mib
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alloc r32=ar.pfs,3,0,4,0
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addl GR_Tag = 175, r0 // Set error tag for underflow
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br.cond.sptk __libm_error_region // Call error support for underflow
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}
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;;
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// Here if x=unorm
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SCALBNL_UNORM:
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{ .mib
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getf.exp GR_signexp_X = FR_Norm_X // Get signexp of normalized x
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nop.i 0
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br.cond.sptk SCALBNL_COMMON // Return to main path
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}
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;;
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GLOBAL_LIBM_END(__libm_scalbnl)
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LOCAL_LIBM_ENTRY(__libm_error_region)
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//
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// Get stack address of N
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//
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.prologue
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{ .mfi
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add GR_Parameter_Y=-32,sp
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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
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}
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//
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// Adjust sp
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//
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{ .mfi
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.fframe 64
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add sp=-64,sp
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nop.f 0
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mov GR_SAVE_GP=gp
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};;
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//
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// Store N on stack in correct position
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// Locate the address of x on stack
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//
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{ .mmi
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st8 [GR_Parameter_Y] = GR_N_as_int,16
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add GR_Parameter_X = 16,sp
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.save b0, GR_SAVE_B0
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mov GR_SAVE_B0=b0
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};;
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//
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// Store x on the stack.
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// Get address for result on stack.
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//
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.body
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{ .mib
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stfe [GR_Parameter_X] = FR_Norm_X
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add GR_Parameter_RESULT = 0,GR_Parameter_Y
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nop.b 0
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}
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{ .mib
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stfe [GR_Parameter_Y] = FR_Result
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add GR_Parameter_Y = -16,GR_Parameter_Y
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br.call.sptk b0=__libm_error_support#
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};;
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//
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// Get location of result on stack
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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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//
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// Get the new result
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//
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{ .mmi
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ldfe FR_Result = [GR_Parameter_RESULT]
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.restore sp
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add sp = 64,sp
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mov b0 = GR_SAVE_B0
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};;
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//
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// Restore gp, ar.pfs and return
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//
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{ .mib
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mov gp = GR_SAVE_GP
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mov ar.pfs = GR_SAVE_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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