| 1 | /* ix87 specific frexp implementation for double. |
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| 2 | Copyright (C) 1997-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <machine/asm.h> |
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| 20 | #include <libm-alias-double.h> |
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| 21 | |
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| 22 | .section .rodata |
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| 23 | |
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| 24 | .align ALIGNARG(4) |
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| 25 | .type two54,@object |
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| 26 | two54: .byte 0, 0, 0, 0, 0, 0, 0x50, 0x43 |
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| 27 | ASM_SIZE_DIRECTIVE(two54) |
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| 28 | |
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| 29 | #ifdef PIC |
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| 30 | #define MO(op) op##@GOTOFF(%edx) |
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| 31 | #else |
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| 32 | #define MO(op) op |
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| 33 | #endif |
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| 34 | |
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| 35 | #define PARMS 4 /* no space for saved regs */ |
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| 36 | #define VAL0 PARMS |
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| 37 | #define VAL1 VAL0+4 |
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| 38 | #define EXPP VAL1+4 |
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| 39 | |
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| 40 | .text |
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| 41 | ENTRY (__frexp) |
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| 42 | |
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| 43 | movl VAL0(%esp), %ecx |
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| 44 | movl VAL1(%esp), %eax |
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| 45 | movl %eax, %edx |
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| 46 | andl $0x7fffffff, %eax |
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| 47 | orl %eax, %ecx |
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| 48 | jz 1f |
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| 49 | xorl %ecx, %ecx |
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| 50 | cmpl $0x7ff00000, %eax |
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| 51 | jae 1f |
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| 52 | |
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| 53 | cmpl $0x00100000, %eax |
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| 54 | jae 2f |
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| 55 | |
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| 56 | fldl VAL0(%esp) |
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| 57 | #ifdef PIC |
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| 58 | LOAD_PIC_REG (dx) |
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| 59 | #endif |
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| 60 | fmull MO(two54) |
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| 61 | movl $-54, %ecx |
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| 62 | fstpl VAL0(%esp) |
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| 63 | fwait |
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| 64 | movl VAL1(%esp), %eax |
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| 65 | movl %eax, %edx |
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| 66 | andl $0x7fffffff, %eax |
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| 67 | |
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| 68 | 2: shrl $20, %eax |
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| 69 | andl $0x800fffff, %edx |
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| 70 | subl $1022, %eax |
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| 71 | orl $0x3fe00000, %edx |
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| 72 | addl %eax, %ecx |
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| 73 | movl %edx, VAL1(%esp) |
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| 74 | |
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| 75 | /* Store %ecx in the variable pointed to by the second argument, |
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| 76 | get the factor from the stack and return. */ |
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| 77 | 1: movl EXPP(%esp), %eax |
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| 78 | fldl VAL0(%esp) |
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| 79 | movl %ecx, (%eax) |
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| 80 | |
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| 81 | ret |
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| 82 | END (__frexp) |
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| 83 | libm_alias_double (__frexp, frexp) |
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| 84 | |
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