| 1 | /* ix87 specific implementation of pow function.
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| 2 | Copyright (C) 1996, 1997, 1998, 1999, 2001, 2004, 2005
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| 3 | Free Software Foundation, Inc.
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| 4 | This file is part of the GNU C Library.
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| 5 | Contributed by Ulrich Drepper <[email protected]>, 1996.
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| 6 |
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| 7 | The GNU C Library is free software; you can redistribute it and/or
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| 8 | modify it under the terms of the GNU Lesser General Public
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| 9 | License as published by the Free Software Foundation; either
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| 10 | version 2.1 of the License, or (at your option) any later version.
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| 11 |
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| 12 | The GNU C Library is distributed in the hope that it will be useful,
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 15 | Lesser General Public License for more details.
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| 16 |
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| 17 | You should have received a copy of the GNU Lesser General Public
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| 18 | License along with the GNU C Library; if not, write to the Free
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| 19 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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| 20 | 02111-1307 USA. */
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| 21 |
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| 22 | /*#include <machine/asm.h>*/
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| 23 | #include <iprt/cdefs.h>
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| 24 |
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| 25 | #ifdef __MINGW32__
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| 26 | # define ASM_TYPE_DIRECTIVE(name,typearg)
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| 27 | # define ASM_SIZE_DIRECTIVE(name)
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| 28 | # define cfi_adjust_cfa_offset(a)
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| 29 | # define C_LABEL(name) _ ## name:
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| 30 | # define C_SYMBOL_NAME(name) _ ## name
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| 31 | # define ASM_GLOBAL_DIRECTIVE .global
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| 32 | # define ALIGNARG(log2) 1<<log2
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| 33 | #elif __APPLE__
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| 34 | # define ASM_TYPE_DIRECTIVE(name,typearg)
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| 35 | # define ASM_SIZE_DIRECTIVE(name)
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| 36 | # define cfi_adjust_cfa_offset(a)
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| 37 | # define C_LABEL(name) _ ## name:
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| 38 | # define C_SYMBOL_NAME(name) _ ## name
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| 39 | # define ASM_GLOBAL_DIRECTIVE .globl
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| 40 | # define ALIGNARG(log2) log2
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| 41 | #else
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| 42 | # define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
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| 43 | # define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
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| 44 | # define C_LABEL(name) name:
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| 45 | # define C_SYMBOL_NAME(name) name
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| 46 | # /* figure this one out. */
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| 47 | # define cfi_adjust_cfa_offset(a)
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| 48 | # define ASM_GLOBAL_DIRECTIVE .global
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| 49 | # define ALIGNARG(log2) 1<<log2
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| 50 | #endif
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| 51 |
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| 52 | #define ENTRY(name) \
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| 53 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name); \
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| 54 | ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function) \
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| 55 | .align ALIGNARG(4); \
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| 56 | C_LABEL(name)
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| 57 |
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| 58 | #undef END
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| 59 | #define END(name) \
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| 60 | ASM_SIZE_DIRECTIVE(name)
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| 61 |
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| 62 | #ifdef __ELF__
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| 63 | .section .rodata
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| 64 | #else
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| 65 | .text
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| 66 | #endif
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| 67 |
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| 68 | .align ALIGNARG(4)
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| 69 | ASM_TYPE_DIRECTIVE(infinity,@object)
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| 70 | inf_zero:
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| 71 | infinity:
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| 72 | .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x7f
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| 73 | ASM_SIZE_DIRECTIVE(infinity)
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| 74 | ASM_TYPE_DIRECTIVE(zero,@object)
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| 75 | zero: .double 0.0
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| 76 | ASM_SIZE_DIRECTIVE(zero)
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| 77 | ASM_TYPE_DIRECTIVE(minf_mzero,@object)
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| 78 | minf_mzero:
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| 79 | minfinity:
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| 80 | .byte 0, 0, 0, 0, 0, 0, 0xf0, 0xff
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| 81 | mzero:
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| 82 | .byte 0, 0, 0, 0, 0, 0, 0, 0x80
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| 83 | ASM_SIZE_DIRECTIVE(minf_mzero)
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| 84 | ASM_TYPE_DIRECTIVE(one,@object)
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| 85 | one: .double 1.0
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| 86 | ASM_SIZE_DIRECTIVE(one)
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| 87 | ASM_TYPE_DIRECTIVE(limit,@object)
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| 88 | limit: .double 0.29
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| 89 | ASM_SIZE_DIRECTIVE(limit)
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| 90 | ASM_TYPE_DIRECTIVE(p63,@object)
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| 91 | p63: .byte 0, 0, 0, 0, 0, 0, 0xe0, 0x43
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| 92 | ASM_SIZE_DIRECTIVE(p63)
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| 93 |
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| 94 | #ifdef PIC
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| 95 | #define MO(op) op##@GOTOFF(%ecx)
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| 96 | #define MOX(op,x,f) op##@GOTOFF(%ecx,x,f)
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| 97 | #else
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| 98 | #define MO(op) op
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| 99 | #define MOX(op,x,f) op(,x,f)
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| 100 | #endif
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| 101 |
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| 102 | .text
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| 103 | //ENTRY(__ieee754_powl)
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| 104 | ENTRY(RT_NOCRT(powl))
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| 105 | #ifdef RT_OS_DARWIN /* 16-byte long double with 8 byte alignment requirements */
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| 106 | fldt 20(%esp) // y
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| 107 | #else
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| 108 | fldt 16(%esp) // y
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| 109 | #endif
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| 110 | fxam
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| 111 |
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| 112 | #ifdef PIC
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| 113 | LOAD_PIC_REG (cx)
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| 114 | #endif
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| 115 |
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| 116 | fnstsw
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| 117 | movb %ah, %dl
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| 118 | andb $0x45, %ah
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| 119 | cmpb $0x40, %ah // is y == 0 ?
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| 120 | je .L11
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| 121 |
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| 122 | cmpb $0x05, %ah // is y == ±inf ?
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| 123 | je .L12
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| 124 |
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| 125 | cmpb $0x01, %ah // is y == NaN ?
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| 126 | je .L30
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| 127 |
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| 128 | fldt 4(%esp) // x : y
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| 129 |
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| 130 | subl $8,%esp
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| 131 | cfi_adjust_cfa_offset (8)
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| 132 |
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| 133 | fxam
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| 134 | fnstsw
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| 135 | movb %ah, %dh
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| 136 | andb $0x45, %ah
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| 137 | cmpb $0x40, %ah
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| 138 | je .L20 // x is ±0
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| 139 |
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| 140 | cmpb $0x05, %ah
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| 141 | je .L15 // x is ±inf
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| 142 |
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| 143 | fxch // y : x
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| 144 |
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| 145 | /* fistpll raises invalid exception for |y| >= 1L<<63. */
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| 146 | fld %st // y : y : x
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| 147 | fabs // |y| : y : x
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| 148 | fcompl MO(p63) // y : x
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| 149 | fnstsw
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| 150 | sahf
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| 151 | jnc .L2
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| 152 |
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| 153 | /* First see whether `y' is a natural number. In this case we
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| 154 | can use a more precise algorithm. */
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| 155 | fld %st // y : y : x
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| 156 | fistpll (%esp) // y : x
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| 157 | fildll (%esp) // int(y) : y : x
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| 158 | fucomp %st(1) // y : x
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| 159 | fnstsw
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| 160 | sahf
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| 161 | jne .L2
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| 162 |
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| 163 | /* OK, we have an integer value for y. */
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| 164 | popl %eax
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| 165 | cfi_adjust_cfa_offset (-4)
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| 166 | popl %edx
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| 167 | cfi_adjust_cfa_offset (-4)
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| 168 | orl $0, %edx
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| 169 | fstp %st(0) // x
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| 170 | jns .L4 // y >= 0, jump
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| 171 | fdivrl MO(one) // 1/x (now referred to as x)
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| 172 | negl %eax
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| 173 | adcl $0, %edx
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| 174 | negl %edx
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| 175 | .L4: fldl MO(one) // 1 : x
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| 176 | fxch
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| 177 |
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| 178 | .L6: shrdl $1, %edx, %eax
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| 179 | jnc .L5
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| 180 | fxch
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| 181 | fmul %st(1) // x : ST*x
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| 182 | fxch
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| 183 | .L5: fmul %st(0), %st // x*x : ST*x
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| 184 | shrl $1, %edx
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| 185 | movl %eax, %ecx
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| 186 | orl %edx, %ecx
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| 187 | jnz .L6
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| 188 | fstp %st(0) // ST*x
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| 189 | ret
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| 190 |
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| 191 | /* y is ±NAN */
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| 192 | .L30: fldt 4(%esp) // x : y
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| 193 | fldl MO(one) // 1.0 : x : y
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| 194 | fucomp %st(1) // x : y
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| 195 | fnstsw
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| 196 | sahf
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| 197 | je .L31
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| 198 | fxch // y : x
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| 199 | .L31: fstp %st(1)
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| 200 | ret
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| 201 |
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| 202 | cfi_adjust_cfa_offset (8)
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| 203 | .align ALIGNARG(4)
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| 204 | .L2: /* y is a real number. */
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| 205 | fxch // x : y
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| 206 | fldl MO(one) // 1.0 : x : y
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| 207 | fld %st(1) // x : 1.0 : x : y
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| 208 | fsub %st(1) // x-1 : 1.0 : x : y
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| 209 | fabs // |x-1| : 1.0 : x : y
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| 210 | fcompl MO(limit) // 1.0 : x : y
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| 211 | fnstsw
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| 212 | fxch // x : 1.0 : y
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| 213 | sahf
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| 214 | ja .L7
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| 215 | fsub %st(1) // x-1 : 1.0 : y
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| 216 | fyl2xp1 // log2(x) : y
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| 217 | jmp .L8
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| 218 |
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| 219 | .L7: fyl2x // log2(x) : y
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| 220 | .L8: fmul %st(1) // y*log2(x) : y
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| 221 | fxam
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| 222 | fnstsw
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| 223 | andb $0x45, %ah
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| 224 | cmpb $0x05, %ah // is y*log2(x) == ±inf ?
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| 225 | je .L28
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| 226 | fst %st(1) // y*log2(x) : y*log2(x)
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| 227 | frndint // int(y*log2(x)) : y*log2(x)
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| 228 | fsubr %st, %st(1) // int(y*log2(x)) : fract(y*log2(x))
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| 229 | fxch // fract(y*log2(x)) : int(y*log2(x))
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| 230 | f2xm1 // 2^fract(y*log2(x))-1 : int(y*log2(x))
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| 231 | faddl MO(one) // 2^fract(y*log2(x)) : int(y*log2(x))
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| 232 | fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
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| 233 | addl $8, %esp
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| 234 | cfi_adjust_cfa_offset (-8)
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| 235 | fstp %st(1) // 2^fract(y*log2(x))*2^int(y*log2(x))
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| 236 | ret
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| 237 |
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| 238 | cfi_adjust_cfa_offset (8)
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| 239 | .L28: fstp %st(1) // y*log2(x)
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| 240 | fldl MO(one) // 1 : y*log2(x)
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| 241 | fscale // 2^(y*log2(x)) : y*log2(x)
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| 242 | addl $8, %esp
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| 243 | cfi_adjust_cfa_offset (-8)
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| 244 | fstp %st(1) // 2^(y*log2(x))
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| 245 | ret
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| 246 |
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| 247 | // pow(x,±0) = 1
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| 248 | .align ALIGNARG(4)
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| 249 | .L11: fstp %st(0) // pop y
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| 250 | fldl MO(one)
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| 251 | ret
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| 252 |
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| 253 | // y == ±inf
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| 254 | .align ALIGNARG(4)
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| 255 | .L12: fstp %st(0) // pop y
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| 256 | fldt 4(%esp) // x
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| 257 | fabs
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| 258 | fcompl MO(one) // < 1, == 1, or > 1
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| 259 | fnstsw
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| 260 | andb $0x45, %ah
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| 261 | cmpb $0x45, %ah
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| 262 | je .L13 // jump if x is NaN
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| 263 |
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| 264 | cmpb $0x40, %ah
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| 265 | je .L14 // jump if |x| == 1
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| 266 |
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| 267 | shlb $1, %ah
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| 268 | xorb %ah, %dl
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| 269 | andl $2, %edx
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| 270 | fldl MOX(inf_zero, %edx, 4)
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| 271 | ret
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| 272 |
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| 273 | .align ALIGNARG(4)
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| 274 | .L14: fldl MO(one)
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| 275 | ret
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| 276 |
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| 277 | .align ALIGNARG(4)
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| 278 | .L13: fldt 4(%esp) // load x == NaN
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| 279 | ret
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| 280 |
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| 281 | cfi_adjust_cfa_offset (8)
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| 282 | .align ALIGNARG(4)
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| 283 | // x is ±inf
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| 284 | .L15: fstp %st(0) // y
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| 285 | testb $2, %dh
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| 286 | jz .L16 // jump if x == +inf
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| 287 |
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| 288 | // We must find out whether y is an odd integer.
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| 289 | fld %st // y : y
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| 290 | fistpll (%esp) // y
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| 291 | fildll (%esp) // int(y) : y
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| 292 | fucompp // <empty>
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| 293 | fnstsw
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| 294 | sahf
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| 295 | jne .L17
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| 296 |
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| 297 | // OK, the value is an integer, but is it odd?
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| 298 | popl %eax
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| 299 | cfi_adjust_cfa_offset (-4)
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| 300 | popl %edx
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| 301 | cfi_adjust_cfa_offset (-4)
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| 302 | andb $1, %al
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| 303 | jz .L18 // jump if not odd
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| 304 | // It's an odd integer.
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| 305 | shrl $31, %edx
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| 306 | fldl MOX(minf_mzero, %edx, 8)
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| 307 | ret
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| 308 |
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| 309 | cfi_adjust_cfa_offset (8)
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| 310 | .align ALIGNARG(4)
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| 311 | .L16: fcompl MO(zero)
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| 312 | addl $8, %esp
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| 313 | cfi_adjust_cfa_offset (-8)
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| 314 | fnstsw
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| 315 | shrl $5, %eax
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| 316 | andl $8, %eax
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| 317 | fldl MOX(inf_zero, %eax, 1)
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| 318 | ret
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| 319 |
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| 320 | cfi_adjust_cfa_offset (8)
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| 321 | .align ALIGNARG(4)
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| 322 | .L17: shll $30, %edx // sign bit for y in right position
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| 323 | addl $8, %esp
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| 324 | cfi_adjust_cfa_offset (-8)
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| 325 | .L18: shrl $31, %edx
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| 326 | fldl MOX(inf_zero, %edx, 8)
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| 327 | ret
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| 328 |
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| 329 | cfi_adjust_cfa_offset (8)
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| 330 | .align ALIGNARG(4)
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| 331 | // x is ±0
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| 332 | .L20: fstp %st(0) // y
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| 333 | testb $2, %dl
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| 334 | jz .L21 // y > 0
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| 335 |
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| 336 | // x is ±0 and y is < 0. We must find out whether y is an odd integer.
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| 337 | testb $2, %dh
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| 338 | jz .L25
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| 339 |
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| 340 | fld %st // y : y
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| 341 | fistpll (%esp) // y
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| 342 | fildll (%esp) // int(y) : y
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| 343 | fucompp // <empty>
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| 344 | fnstsw
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| 345 | sahf
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| 346 | jne .L26
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| 347 |
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| 348 | // OK, the value is an integer, but is it odd?
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| 349 | popl %eax
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| 350 | cfi_adjust_cfa_offset (-4)
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| 351 | popl %edx
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| 352 | cfi_adjust_cfa_offset (-4)
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| 353 | andb $1, %al
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| 354 | jz .L27 // jump if not odd
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| 355 | // It's an odd integer.
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| 356 | // Raise divide-by-zero exception and get minus infinity value.
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| 357 | fldl MO(one)
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| 358 | fdivl MO(zero)
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| 359 | fchs
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| 360 | ret
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| 361 |
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| 362 | cfi_adjust_cfa_offset (8)
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| 363 | .L25: fstp %st(0)
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| 364 | .L26: addl $8, %esp
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| 365 | cfi_adjust_cfa_offset (-8)
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| 366 | .L27: // Raise divide-by-zero exception and get infinity value.
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| 367 | fldl MO(one)
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| 368 | fdivl MO(zero)
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| 369 | ret
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| 370 |
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| 371 | cfi_adjust_cfa_offset (8)
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| 372 | .align ALIGNARG(4)
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| 373 | // x is ±0 and y is > 0. We must find out whether y is an odd integer.
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| 374 | .L21: testb $2, %dh
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| 375 | jz .L22
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| 376 |
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| 377 | fld %st // y : y
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| 378 | fistpll (%esp) // y
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| 379 | fildll (%esp) // int(y) : y
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| 380 | fucompp // <empty>
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| 381 | fnstsw
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| 382 | sahf
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| 383 | jne .L23
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| 384 |
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| 385 | // OK, the value is an integer, but is it odd?
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| 386 | popl %eax
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| 387 | cfi_adjust_cfa_offset (-4)
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| 388 | popl %edx
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| 389 | cfi_adjust_cfa_offset (-4)
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| 390 | andb $1, %al
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| 391 | jz .L24 // jump if not odd
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| 392 | // It's an odd integer.
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| 393 | fldl MO(mzero)
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| 394 | ret
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| 395 |
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| 396 | cfi_adjust_cfa_offset (8)
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| 397 | .L22: fstp %st(0)
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| 398 | .L23: addl $8, %esp // Don't use 2 x pop
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| 399 | cfi_adjust_cfa_offset (-8)
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| 400 | .L24: fldl MO(zero)
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| 401 | ret
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| 402 |
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| 403 | END(RT_NOCRT(powl))
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| 404 | //END(__ieee754_powl)
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