projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 6bc31da0 | 1 | /* ix87 specific implementation of exp(x)-1. |
| a334319f | 2 | Copyright (C) 1996, 1997 Free Software Foundation, Inc. |
| 6bc31da0 UD |
3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. | |
| 5 | Based on code by John C. Bowman <bowman@ipp-garching.mpg.de>. | |
| 5290baf0 | 6 | Corrections by H.J. Lu (hjl@gnu.ai.mit.edu), 1997. |
| 6bc31da0 UD |
7 | |
| 8 | The GNU C Library is free software; you can redistribute it and/or | |
| 41bdb6e2 AJ |
9 | modify it under the terms of the GNU Lesser General Public |
| 10 | License as published by the Free Software Foundation; either | |
| 11 | version 2.1 of the License, or (at your option) any later version. | |
| 6bc31da0 UD |
12 | |
| 13 | The GNU C Library is distributed in the hope that it will be useful, | |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 41bdb6e2 | 16 | Lesser General Public License for more details. |
| 6bc31da0 | 17 | |
| 41bdb6e2 AJ |
18 | You should have received a copy of the GNU Lesser General Public |
| 19 | License along with the GNU C Library; if not, write to the Free | |
| 20 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
| 21 | 02111-1307 USA. */ | |
| 6bc31da0 UD |
22 | |
| 23 | /* Using: e^x - 1 = 2^(x * log2(e)) - 1 */ | |
| 24 | ||
| 25 | #include <machine/asm.h> | |
| 26 | ||
| 27 | #ifdef __ELF__ | |
| 28 | .section .rodata | |
| 29 | #else | |
| 30 | .text | |
| 31 | #endif | |
| 32 | .align ALIGNARG(4) | |
| 0d8733c4 UD |
33 | ASM_TYPE_DIRECTIVE(minus1,@object) |
| 34 | minus1: .double -1.0 | |
| 35 | ASM_SIZE_DIRECTIVE(minus1) | |
| 6bc31da0 UD |
36 | ASM_TYPE_DIRECTIVE(one,@object) |
| 37 | one: .double 1.0 | |
| 38 | ASM_SIZE_DIRECTIVE(one) | |
| 39 | ASM_TYPE_DIRECTIVE(l2e,@object) | |
| 40 | l2e: .tfloat 1.442695040888963407359924681002 | |
| 41 | ASM_SIZE_DIRECTIVE(l2e) | |
| 42 | ||
| 43 | #ifdef PIC | |
| 44 | #define MO(op) op##@GOTOFF(%edx) | |
| 45 | #else | |
| 46 | #define MO(op) op | |
| 47 | #endif | |
| 48 | ||
| 49 | .text | |
| 50 | ENTRY(__expm1) | |
| 51 | fldl 4(%esp) // x | |
| 52 | fxam // Is NaN or +-Inf? | |
| 53 | fstsw %ax | |
| c57abfa7 UD |
54 | movb $0x45, %ch |
| 55 | andb %ah, %ch | |
| 56 | cmpb $0x40, %ch | |
| 57 | je 3f // If +-0, jump. | |
| 6bc31da0 | 58 | #ifdef PIC |
| a334319f UD |
59 | call 1f |
| 60 | 1: popl %edx | |
| 61 | addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx | |
| 6bc31da0 | 62 | #endif |
| 6bc31da0 | 63 | cmpb $0x05, %ch |
| c57abfa7 | 64 | je 2f // If +-Inf, jump. |
| 6bc31da0 UD |
65 | |
| 66 | fldt MO(l2e) // log2(e) : x | |
| 67 | fmulp // log2(e)*x | |
| 68 | fld %st // log2(e)*x : log2(e)*x | |
| 69 | frndint // int(log2(e)*x) : log2(e)*x | |
| 5290baf0 | 70 | fsubr %st, %st(1) // int(log2(e)*x) : fract(log2(e)*x) |
| 6bc31da0 UD |
71 | fxch // fract(log2(e)*x) : int(log2(e)*x) |
| 72 | f2xm1 // 2^fract(log2(e)*x)-1 : int(log2(e)*x) | |
| 73 | fscale // 2^(log2(e)*x)-2^int(log2(e)*x) : int(log2(e)*x) | |
| 74 | fxch // int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) | |
| 75 | fldl MO(one) // 1 : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) | |
| 5290baf0 UD |
76 | fscale // 2^int(log2(e)*x) : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) |
| 77 | fsubrl MO(one) // 1-2^int(log2(e)*x) : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) | |
| 78 | fstp %st(1) // 1-2^int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x) | |
| 79 | fsubrp %st, %st(1) // 2^(log2(e)*x) | |
| 6bc31da0 UD |
80 | ret |
| 81 | ||
| 82 | 2: testl $0x200, %eax // Test sign. | |
| 83 | jz 3f // If positive, jump. | |
| 0d8733c4 UD |
84 | fstp %st |
| 85 | fldl MO(minus1) // Set result to -1.0. | |
| 6bc31da0 UD |
86 | 3: ret |
| 87 | END(__expm1) | |
| 88 | weak_alias (__expm1, expm1) |