codekingpro/portable-devtools

1// Copyright 2010 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4 5#include "textflag.h"6 7// The method is based on a paper by Naoki Shibata: "Efficient evaluation8// methods of elementary functions suitable for SIMD computation", Proc.9// of International Supercomputing Conference 2010 (ISC'10), pp. 25 -- 3210// (May 2010). The paper is available at11// https://link.springer.com/article/10.1007/s00450-010-0108-212//13// The original code and the constants below are from the author's14// implementation available at http://freshmeat.net/projects/sleef.15// The README file says, "The software is in public domain.16// You can use the software without any obligation."17//18// This code is a simplified version of the original.19 20#define LN2 0.6931471805599453094172321214581766 // log_e(2)21#define LOG2E 1.4426950408889634073599246810018920 // 1/LN222#define LN2U 0.69314718055966295651160180568695068359375 // upper half LN223#define LN2L 0.28235290563031577122588448175013436025525412068e-12 // lower half LN224#define PosInf 0x7FF000000000000025#define NegInf 0xFFF000000000000026#define Overflow 7.09782712893384e+0227 28DATA exprodata<>+0(SB)/8, $0.529DATA exprodata<>+8(SB)/8, $1.030DATA exprodata<>+16(SB)/8, $2.031DATA exprodata<>+24(SB)/8, $1.6666666666666666667e-132DATA exprodata<>+32(SB)/8, $4.1666666666666666667e-233DATA exprodata<>+40(SB)/8, $8.3333333333333333333e-334DATA exprodata<>+48(SB)/8, $1.3888888888888888889e-335DATA exprodata<>+56(SB)/8, $1.9841269841269841270e-436DATA exprodata<>+64(SB)/8, $2.4801587301587301587e-537GLOBL exprodata<>+0(SB), RODATA, $7238 39// func Exp(x float64) float6440TEXT ·archExp(SB),NOSPLIT,$041	// test bits for not-finite42	MOVQ    x+0(FP), BX43	MOVQ    $~(1<<63), AX // sign bit mask44	MOVQ    BX, DX45	ANDQ    AX, DX46	MOVQ    $PosInf, AX47	CMPQ    AX, DX48	JLE     notFinite49	// check if argument will overflow50	MOVQ    BX, X051	MOVSD   $Overflow, X152	COMISD  X1, X053	JA      overflow54	MOVSD   $LOG2E, X155	MULSD   X0, X156	CVTSD2SL X1, BX // BX = exponent57	CVTSL2SD BX, X158	CMPB ·useFMA(SB), $159	JE   avxfma60	MOVSD   $LN2U, X261	MULSD   X1, X262	SUBSD   X2, X063	MOVSD   $LN2L, X264	MULSD   X1, X265	SUBSD   X2, X066	// reduce argument67	MULSD   $0.0625, X068	// Taylor series evaluation69	MOVSD   exprodata<>+64(SB), X170	MULSD   X0, X171	ADDSD   exprodata<>+56(SB), X172	MULSD   X0, X173	ADDSD   exprodata<>+48(SB), X174	MULSD   X0, X175	ADDSD   exprodata<>+40(SB), X176	MULSD   X0, X177	ADDSD   exprodata<>+32(SB), X178	MULSD   X0, X179	ADDSD   exprodata<>+24(SB), X180	MULSD   X0, X181	ADDSD   exprodata<>+0(SB), X182	MULSD   X0, X183	ADDSD   exprodata<>+8(SB), X184	MULSD   X1, X085	MOVSD   exprodata<>+16(SB), X186	ADDSD   X0, X187	MULSD   X1, X088	MOVSD   exprodata<>+16(SB), X189	ADDSD   X0, X190	MULSD   X1, X091	MOVSD   exprodata<>+16(SB), X192	ADDSD   X0, X193	MULSD   X1, X094	MOVSD   exprodata<>+16(SB), X195	ADDSD   X0, X196	MULSD   X1, X097	ADDSD exprodata<>+8(SB), X098	// return fr * 2**exponent99ldexp:100	ADDL    $0x3FF, BX // add bias101	JLE     denormal102	CMPL    BX, $0x7FF103	JGE     overflow104lastStep:105	SHLQ    $52, BX106	MOVQ    BX, X1107	MULSD   X1, X0108	MOVSD   X0, ret+8(FP)109	RET110notFinite:111	// test bits for -Inf112	MOVQ    $NegInf, AX113	CMPQ    AX, BX114	JNE     notNegInf115	// -Inf, return 0116underflow: // return 0117	MOVQ    $0, ret+8(FP)118	RET119overflow: // return +Inf120	MOVQ    $PosInf, BX121notNegInf: // NaN or +Inf, return x122	MOVQ    BX, ret+8(FP)123	RET124denormal:125	CMPL    BX, $-52126	JL      underflow127	ADDL    $0x3FE, BX // add bias - 1128	SHLQ    $52, BX129	MOVQ    BX, X1130	MULSD   X1, X0131	MOVQ    $1, BX132	JMP     lastStep133 134avxfma:135	MOVSD   $LN2U, X2136	VFNMADD231SD X2, X1, X0137	MOVSD   $LN2L, X2138	VFNMADD231SD X2, X1, X0139	// reduce argument140	MULSD   $0.0625, X0141	// Taylor series evaluation142	MOVSD   exprodata<>+64(SB), X1143	VFMADD213SD exprodata<>+56(SB), X0, X1144	VFMADD213SD exprodata<>+48(SB), X0, X1145	VFMADD213SD exprodata<>+40(SB), X0, X1146	VFMADD213SD exprodata<>+32(SB), X0, X1147	VFMADD213SD exprodata<>+24(SB), X0, X1148	VFMADD213SD exprodata<>+0(SB), X0, X1149	VFMADD213SD exprodata<>+8(SB), X0, X1150	MULSD   X1, X0151	VADDSD exprodata<>+16(SB), X0, X1152	MULSD   X1, X0153	VADDSD exprodata<>+16(SB), X0, X1154	MULSD   X1, X0155	VADDSD exprodata<>+16(SB), X0, X1156	MULSD   X1, X0157	VADDSD exprodata<>+16(SB), X0, X1158	VFMADD213SD   exprodata<>+8(SB), X1, X0159	JMP ldexp160