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author | Liubov Dmitrieva <liubov.dmitrieva@gmail.com> | 2012-05-14 11:18:44 +0200 |
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committer | Andreas Jaeger <aj@suse.de> | 2012-05-14 11:23:56 +0200 |
commit | d7bb4c428aed3126614b999336397e9e55e6f486 (patch) | |
tree | 5ef5998ab4f1fdae4dbe320e74f2c45c4678feae /sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S | |
parent | 9dc4e1fbfcebda9c5f1eaab1d777cc0bdbfafa47 (diff) | |
download | glibc-d7bb4c428aed3126614b999336397e9e55e6f486.tar.gz glibc-d7bb4c428aed3126614b999336397e9e55e6f486.tar.xz glibc-d7bb4c428aed3126614b999336397e9e55e6f486.zip |
Add optimized expf for x86
2012-05-14 Liubov Dmitrieva <liubov.dmitrieva@gmail.com> * sysdeps/i386/i686/fpu/multiarch/Makefile: New file. * sysdeps/i386/i686fpu/multiarch/e_expf.c: New file. * sysdeps/i386/i686fpu/multiarch/e_expf-ia32.S: New file. * sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S: New file.
Diffstat (limited to 'sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S')
-rw-r--r-- | sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S b/sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S new file mode 100644 index 0000000000..31cdffdb00 --- /dev/null +++ b/sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S @@ -0,0 +1,324 @@ +/* SSE2 version of __ieee754_expf and __expf_finite + Copyright (C) 2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + + +#include <sysdep.h> + +/* Short algorithm description: + * + * Let K = 64 (table size). + * e^x = 2^(x/log(2)) = 2^n * T[j] * (1 + P(y)) + * where + * x = m*log(2)/K + y, y in [0.0..log(2)/K] + * m = n*K + j, m,n,j - signed integer, j in [0..K-1] + * values of 2^(j/K) are tabulated as T[j]. + * + * P(y) is a minimax polynomial approximation of expf(x)-1 + * on small interval [0.0..log(2)/K]. + * + * P(y) = P3*y*y*y*y + P2*y*y*y + P1*y*y + P0*y, calculated as + * z = y*y; P(y) = (P3*z + P1)*z + (P2*z + P0)*y + * + * Special cases: + * __ieee754_expf_sse2(NaN) = NaN + * __ieee754_expf_sse2(+INF) = +INF + * __ieee754_expf_sse2(-INF) = 0 + * __ieee754_expf_sse2(x) = 1 for subnormals + * for finite argument, only __ieee754_expf_sse2(0)=1 is exact + * __ieee754_expf_sse2(x) overflows if x>700 + * __ieee754_expf_sse2(x) underflows if x<-700 + * + * Note: + * For |x|<700, __ieee754_expf_sse2 computes result in double precision, + * with accuracy a bit more than needed for expf, and does not round it + * to single precision. + */ + + +#ifdef PIC +# define MO1(symbol) L(symbol)##@GOTOFF(%edx) +# define MO2(symbol,reg2,_scale) L(symbol)##@GOTOFF(%edx,reg2,_scale) +#else +# define MO1(symbol) L(symbol) +# define MO2(symbol,reg2,_scale) L(symbol)(,reg2,_scale) +#endif + + .text +ENTRY(__ieee754_expf_sse2) + /* Input: single precision x on stack at address 4(%esp) */ + +#ifdef PIC + LOAD_PIC_REG(dx) +#endif + + cvtss2sd 4(%esp), %xmm1 /* Convert x to double precision */ + mov 4(%esp), %ecx /* Copy x */ + movsd MO1(DP_KLN2), %xmm2 /* DP K/log(2) */ + movsd MO1(DP_P2), %xmm3 /* DP P2 */ + movl %ecx, %eax /* x */ + mulsd %xmm1, %xmm2 /* DP x*K/log(2) */ + andl $0x7fffffff, %ecx /* |x| */ + cmpl $0x442f0000, %ecx /* |x|<700 ? */ + movsd MO1(DP_P3), %xmm4 /* DP P3 */ + addsd MO1(DP_RS), %xmm2 /* DP x*K/log(2)+RS */ + jae L(special_paths) + + /* Here if |x|<700 */ + cmpl $0x31800000, %ecx /* |x|<2^(-28) ? */ + jb L(small_arg) + + /* Main path: here if 2^(-28)<=|x|<700 */ + cvtsd2ss %xmm2, %xmm2 /* SP x*K/log(2)+RS */ + movd %xmm2, %eax /* bits of n*K+j with trash */ + subss MO1(SP_RS), %xmm2 /* SP t=round(x*K/log(2)) */ + movl %eax, %ecx /* n*K+j with trash */ + cvtss2sd %xmm2, %xmm2 /* DP t */ + andl $0x3f, %eax /* bits of j */ + mulsd MO1(DP_NLN2K), %xmm2 /* DP -t*log(2)/K */ + andl $0xffffffc0, %ecx /* bits of n */ +#ifdef __AVX__ + vaddsd %xmm1, %xmm2, %xmm0 /* DP y=x-t*log(2)/K */ + vmulsd %xmm0, %xmm0, %xmm2 /* DP z=y*y */ +#else + addsd %xmm1, %xmm2 /* DP y=x-t*log(2)/K */ + movaps %xmm2, %xmm0 /* DP y */ + mulsd %xmm2, %xmm2 /* DP z=y*y */ +#endif + mulsd %xmm2, %xmm4 /* DP P3*z */ + addl $0xffc0, %ecx /* bits of n + DP exponent bias */ + mulsd %xmm2, %xmm3 /* DP P2*z */ + shrl $2, %ecx /* High 2 bytes of DP 2^n */ + pxor %xmm1, %xmm1 /* clear %xmm1 */ + addsd MO1(DP_P1), %xmm4 /* DP P3*z+P1 */ + addsd MO1(DP_P0), %xmm3 /* DP P2*z+P0 */ + pinsrw $3, %ecx, %xmm1 /* DP 2^n */ + mulsd %xmm2, %xmm4 /* DP (P3*z+P1)*z */ + mulsd %xmm3, %xmm0 /* DP (P2*z+P0)*y */ + addsd %xmm4, %xmm0 /* DP P(y) */ + mulsd MO2(DP_T,%eax,8), %xmm0 /* DP P(y)*T[j] */ + addsd MO2(DP_T,%eax,8), %xmm0 /* DP T[j]*(P(y)+1) */ + mulsd %xmm1, %xmm0 /* DP result=2^n*(T[j]*(P(y)+1)) */ + + lea -8(%esp), %esp /* Borrow 8 bytes of stack frame */ + movsd %xmm0, 0(%esp) /* Move result from sse... */ + fldl 0(%esp) /* ...to FPU. */ + lea 8(%esp), %esp /* Return back 8 bytes of stack frame */ + ret + + .p2align 4 +L(small_arg): + /* Here if 0<=|x|<2^(-28) */ + movss 4(%esp), %xmm0 /* load x */ + addss MO1(SP_ONE), %xmm0 /* 1.0 + x */ + /* Return 1.0 with inexact raised, except for x==0 */ + jmp L(epilogue) + + .p2align 4 +L(special_paths): + /* Here if x is NaN, or Inf, or finite |x|>=700 */ + movss 4(%esp), %xmm0 /* load x */ + + cmpl $0x7f800000, %ecx /* |x| is finite ? */ + jae L(arg_inf_or_nan) + + /* Here if finite |x|>=700 */ + testl $0x80000000, %eax /* sign of x nonzero ? */ + je L(res_overflow) + + /* Here if finite x<=-700 */ + movss MO1(SP_SMALL), %xmm0 /* load small value 2^(-100) */ + mulss %xmm0, %xmm0 /* Return underflowed result (zero or subnormal) */ + jmp L(epilogue) + + .p2align 4 +L(res_overflow): + /* Here if finite x>=700 */ + movss MO1(SP_LARGE), %xmm0 /* load large value 2^100 */ + mulss %xmm0, %xmm0 /* Return overflowed result (Inf or max normal) */ + jmp L(epilogue) + + .p2align 4 +L(arg_inf_or_nan): + /* Here if |x| is Inf or NAN */ + jne L(arg_nan) /* |x| is Inf ? */ + + /* Here if |x| is Inf */ + shrl $31, %eax /* Get sign bit of x */ + movss MO2(SP_INF_0,%eax,4), %xmm0/* return zero or Inf, depending on sign of x */ + jmp L(epilogue) + + .p2align 4 +L(arg_nan): + /* Here if |x| is NaN */ + addss %xmm0, %xmm0 /* Return x+x (raise invalid) */ + + .p2align 4 +L(epilogue): + lea -4(%esp), %esp /* Borrow 4 bytes of stack frame */ + movss %xmm0, 0(%esp) /* Move result from sse... */ + flds 0(%esp) /* ...to FPU. */ + lea 4(%esp), %esp /* Return back 4 bytes of stack frame */ + ret +END(__ieee754_expf_sse2) + + .section .rodata, "a" + .p2align 3 +L(DP_T): /* table of double precision values 2^(j/K) for j=[0..K-1] */ + .long 0x00000000, 0x3ff00000 + .long 0x3e778061, 0x3ff02c9a + .long 0xd3158574, 0x3ff059b0 + .long 0x18759bc8, 0x3ff08745 + .long 0x6cf9890f, 0x3ff0b558 + .long 0x32d3d1a2, 0x3ff0e3ec + .long 0xd0125b51, 0x3ff11301 + .long 0xaea92de0, 0x3ff1429a + .long 0x3c7d517b, 0x3ff172b8 + .long 0xeb6fcb75, 0x3ff1a35b + .long 0x3168b9aa, 0x3ff1d487 + .long 0x88628cd6, 0x3ff2063b + .long 0x6e756238, 0x3ff2387a + .long 0x65e27cdd, 0x3ff26b45 + .long 0xf51fdee1, 0x3ff29e9d + .long 0xa6e4030b, 0x3ff2d285 + .long 0x0a31b715, 0x3ff306fe + .long 0xb26416ff, 0x3ff33c08 + .long 0x373aa9cb, 0x3ff371a7 + .long 0x34e59ff7, 0x3ff3a7db + .long 0x4c123422, 0x3ff3dea6 + .long 0x21f72e2a, 0x3ff4160a + .long 0x6061892d, 0x3ff44e08 + .long 0xb5c13cd0, 0x3ff486a2 + .long 0xd5362a27, 0x3ff4bfda + .long 0x769d2ca7, 0x3ff4f9b2 + .long 0x569d4f82, 0x3ff5342b + .long 0x36b527da, 0x3ff56f47 + .long 0xdd485429, 0x3ff5ab07 + .long 0x15ad2148, 0x3ff5e76f + .long 0xb03a5585, 0x3ff6247e + .long 0x82552225, 0x3ff66238 + .long 0x667f3bcd, 0x3ff6a09e + .long 0x3c651a2f, 0x3ff6dfb2 + .long 0xe8ec5f74, 0x3ff71f75 + .long 0x564267c9, 0x3ff75feb + .long 0x73eb0187, 0x3ff7a114 + .long 0x36cf4e62, 0x3ff7e2f3 + .long 0x994cce13, 0x3ff82589 + .long 0x9b4492ed, 0x3ff868d9 + .long 0x422aa0db, 0x3ff8ace5 + .long 0x99157736, 0x3ff8f1ae + .long 0xb0cdc5e5, 0x3ff93737 + .long 0x9fde4e50, 0x3ff97d82 + .long 0x82a3f090, 0x3ff9c491 + .long 0x7b5de565, 0x3ffa0c66 + .long 0xb23e255d, 0x3ffa5503 + .long 0x5579fdbf, 0x3ffa9e6b + .long 0x995ad3ad, 0x3ffae89f + .long 0xb84f15fb, 0x3ffb33a2 + .long 0xf2fb5e47, 0x3ffb7f76 + .long 0x904bc1d2, 0x3ffbcc1e + .long 0xdd85529c, 0x3ffc199b + .long 0x2e57d14b, 0x3ffc67f1 + .long 0xdcef9069, 0x3ffcb720 + .long 0x4a07897c, 0x3ffd072d + .long 0xdcfba487, 0x3ffd5818 + .long 0x03db3285, 0x3ffda9e6 + .long 0x337b9b5f, 0x3ffdfc97 + .long 0xe78b3ff6, 0x3ffe502e + .long 0xa2a490da, 0x3ffea4af + .long 0xee615a27, 0x3ffefa1b + .long 0x5b6e4540, 0x3fff5076 + .long 0x819e90d8, 0x3fffa7c1 + ASM_TYPE_DIRECTIVE(L(DP_T), @object) + ASM_SIZE_DIRECTIVE(L(DP_T)) + + .section .rodata.cst8,"aM",@progbits,8 + .p2align 3 +L(DP_KLN2): /* double precision K/log(2) */ + .long 0x652b82fe, 0x40571547 + ASM_TYPE_DIRECTIVE(L(DP_KLN2), @object) + ASM_SIZE_DIRECTIVE(L(DP_KLN2)) + + .p2align 3 +L(DP_NLN2K): /* double precision -log(2)/K */ + .long 0xfefa39ef, 0xbf862e42 + ASM_TYPE_DIRECTIVE(L(DP_NLN2K), @object) + ASM_SIZE_DIRECTIVE(L(DP_NLN2K)) + + .p2align 3 +L(DP_RS): /* double precision 2^23+2^22 */ + .long 0x00000000, 0x41680000 + ASM_TYPE_DIRECTIVE(L(DP_RS), @object) + ASM_SIZE_DIRECTIVE(L(DP_RS)) + + .p2align 3 +L(DP_P3): /* double precision polynomial coefficient P3 */ + .long 0xeb78fa85, 0x3fa56420 + ASM_TYPE_DIRECTIVE(L(DP_P3), @object) + ASM_SIZE_DIRECTIVE(L(DP_P3)) + + .p2align 3 +L(DP_P1): /* double precision polynomial coefficient P1 */ + .long 0x008d6118, 0x3fe00000 + ASM_TYPE_DIRECTIVE(L(DP_P1), @object) + ASM_SIZE_DIRECTIVE(L(DP_P1)) + + .p2align 3 +L(DP_P2): /* double precision polynomial coefficient P2 */ + .long 0xda752d4f, 0x3fc55550 + ASM_TYPE_DIRECTIVE(L(DP_P2), @object) + ASM_SIZE_DIRECTIVE(L(DP_P2)) + + .p2align 3 +L(DP_P0): /* double precision polynomial coefficient P0 */ + .long 0xffffe7c6, 0x3fefffff + ASM_TYPE_DIRECTIVE(L(DP_P0), @object) + ASM_SIZE_DIRECTIVE(L(DP_P0)) + + .p2align 2 +L(SP_INF_0): + .long 0x7f800000 /* single precision Inf */ + .long 0 /* single precision zero */ + ASM_TYPE_DIRECTIVE(L(SP_INF_0), @object) + ASM_SIZE_DIRECTIVE(L(SP_INF_0)) + + .section .rodata.cst4,"aM",@progbits,4 + .p2align 2 +L(SP_RS): /* single precision 2^23+2^22 */ + .long 0x4b400000 + ASM_TYPE_DIRECTIVE(L(SP_RS), @object) + ASM_SIZE_DIRECTIVE(L(SP_RS)) + + .p2align 2 +L(SP_SMALL): /* single precision small value 2^(-100) */ + .long 0x0d800000 + ASM_TYPE_DIRECTIVE(L(SP_SMALL), @object) + ASM_SIZE_DIRECTIVE(L(SP_SMALL)) + + .p2align 2 +L(SP_LARGE): /* single precision large value 2^100 */ + .long 0x71800000 + ASM_TYPE_DIRECTIVE(L(SP_LARGE), @object) + ASM_SIZE_DIRECTIVE(L(SP_LARGE)) + + .p2align 2 +L(SP_ONE): /* single precision 1.0 */ + .long 0x3f800000 + ASM_TYPE_DIRECTIVE(L(SP_ONE), @object) + ASM_SIZE_DIRECTIVE(L(SP_ONE)) + +strong_alias (__ieee754_expf_sse2, __expf_finite_sse2) |