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Diffstat (limited to 'sysdeps/libm-i387/s_expm1.S')
| -rw-r--r-- | sysdeps/libm-i387/s_expm1.S | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/sysdeps/libm-i387/s_expm1.S b/sysdeps/libm-i387/s_expm1.S new file mode 100644 index 0000000000..2685d6e770 --- /dev/null +++ b/sysdeps/libm-i387/s_expm1.S @@ -0,0 +1,83 @@ +/* ix87 specific implementation of exp(x)-1. + Copyright (C) 1996 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. + Based on code by John C. Bowman <bowman@ipp-garching.mpg.de>. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + + /* Using: e^x - 1 = 2^(x * log2(e)) - 1 */ + +#include <machine/asm.h> + +#ifdef __ELF__ + .section .rodata +#else + .text +#endif + .align ALIGNARG(4) + ASM_TYPE_DIRECTIVE(zero,@object) +zero: .double 0.0 + ASM_SIZE_DIRECTIVE(zero) + ASM_TYPE_DIRECTIVE(one,@object) +one: .double 1.0 + ASM_SIZE_DIRECTIVE(one) + ASM_TYPE_DIRECTIVE(l2e,@object) +l2e: .tfloat 1.442695040888963407359924681002 + ASM_SIZE_DIRECTIVE(l2e) + +#ifdef PIC +#define MO(op) op##@GOTOFF(%edx) +#else +#define MO(op) op +#endif + + .text +ENTRY(__expm1) + fldl 4(%esp) // x + fxam // Is NaN or +-Inf? + fstsw %ax +#ifdef PIC + call 1f +1: popl %edx + addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx +#endif + movb $0x45, %ch + andb %ah, %ch + cmpb $0x05, %ch + je 2f // Is +-Inf, jump. + + fldt MO(l2e) // log2(e) : x + fmulp // log2(e)*x + fld %st // log2(e)*x : log2(e)*x + frndint // int(log2(e)*x) : log2(e)*x + fsub %st, %st(1) // int(log2(e)*x) : fract(log2(e)*x) + fxch // fract(log2(e)*x) : int(log2(e)*x) + f2xm1 // 2^fract(log2(e)*x)-1 : int(log2(e)*x) + fscale // 2^(log2(e)*x)-2^int(log2(e)*x) : int(log2(e)*x) + fxch // int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) + fldl MO(one) // 1 : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) + fscale // 2^int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) + faddp // 2^(log2(e)*x) + fsubl MO(one) + ret + +2: testl $0x200, %eax // Test sign. + jz 3f // If positive, jump. + fldl MO(zero) // Set result to 0. +3: ret +END(__expm1) +weak_alias (__expm1, expm1) |