mirror of
https://github.com/FFmpeg/FFmpeg.git
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bbe95f7353
From x86inc: > On AMD cpus <=K10, an ordinary ret is slow if it immediately follows either > a branch or a branch target. So switch to a 2-byte form of ret in that case. > We can automatically detect "follows a branch", but not a branch target. > (SSSE3 is a sufficient condition to know that your cpu doesn't have this problem.) x86inc can automatically determine whether to use REP_RET rather than REP in most of these cases, so impact is minimal. Additionally, a few REP_RETs were used unnecessary, despite the return being nowhere near a branch. The only CPUs affected were AMD K10s, made between 2007 and 2011, 16 years ago and 12 years ago, respectively. In the future, everyone involved with x86inc should consider dropping REP_RETs altogether.
245 lines
5.9 KiB
NASM
245 lines
5.9 KiB
NASM
;*****************************************************************************
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;* Assembly testing and benchmarking tool
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;* Copyright (c) 2008 Loren Merritt
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;* Copyright (c) 2012 Henrik Gramner
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;*
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;* This file is part of FFmpeg.
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;*
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;* FFmpeg is free software; you can redistribute it and/or modify
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;* it under the terms of the GNU General Public License as published by
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;* the Free Software Foundation; either version 2 of the License, or
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;* (at your option) any later version.
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;*
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;* FFmpeg is distributed in the hope that it will be useful,
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;* but WITHOUT ANY WARRANTY; without even the implied warranty of
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;* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;* GNU General Public License for more details.
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;*
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;* You should have received a copy of the GNU General Public License
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;* along with this program; if not, write to the Free Software
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;* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA.
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;*****************************************************************************
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%define private_prefix checkasm
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%include "libavutil/x86/x86inc.asm"
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SECTION_RODATA
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error_message: db "failed to preserve register", 0
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error_message_emms: db "failed to issue emms", 0
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%if ARCH_X86_64
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; just random numbers to reduce the chance of incidental match
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ALIGN 16
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x6: dq 0x1a1b2550a612b48c,0x79445c159ce79064
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x7: dq 0x2eed899d5a28ddcd,0x86b2536fcd8cf636
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x8: dq 0xb0856806085e7943,0x3f2bf84fc0fcca4e
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x9: dq 0xacbd382dcf5b8de2,0xd229e1f5b281303f
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x10: dq 0x71aeaff20b095fd9,0xab63e2e11fa38ed9
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x11: dq 0x89b0c0765892729a,0x77d410d5c42c882d
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x12: dq 0xc45ea11a955d8dd5,0x24b3c1d2a024048b
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x13: dq 0x2e8ec680de14b47c,0xdd7b8919edd42786
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x14: dq 0x135ce6888fa02cbf,0x11e53e2b2ac655ef
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x15: dq 0x011ff554472a7a10,0x6de8f4c914c334d5
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n7: dq 0x21f86d66c8ca00ce
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n8: dq 0x75b6ba21077c48ad
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n9: dq 0xed56bb2dcb3c7736
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n10: dq 0x8bda43d3fd1a7e06
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n11: dq 0xb64a9c9e5d318408
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n12: dq 0xdf9a54b303f1d3a3
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n13: dq 0x4a75479abd64e097
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n14: dq 0x249214109d5d1c88
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%endif
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SECTION .text
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cextern fail_func
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; max number of args used by any asm function.
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; (max_args % 4) must equal 3 for stack alignment
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%define max_args 15
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%if ARCH_X86_64
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;-----------------------------------------------------------------------------
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; int checkasm_stack_clobber(uint64_t clobber, ...)
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;-----------------------------------------------------------------------------
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cglobal stack_clobber, 1,2
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; Clobber the stack with junk below the stack pointer
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%define argsize (max_args+6)*8
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SUB rsp, argsize
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mov r1, argsize-8
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.loop:
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mov [rsp+r1], r0
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sub r1, 8
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jge .loop
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ADD rsp, argsize
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RET
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%if WIN64
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%assign free_regs 7
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DECLARE_REG_TMP 4
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%else
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%assign free_regs 9
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DECLARE_REG_TMP 7
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%endif
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%macro report_fail 1
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mov r9, rax
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mov r10, rdx
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lea r0, [%1]
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xor eax, eax
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call fail_func
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mov rdx, r10
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mov rax, r9
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%endmacro
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;-----------------------------------------------------------------------------
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; void checkasm_checked_call(void *func, ...)
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;-----------------------------------------------------------------------------
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INIT_XMM
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%macro CHECKED_CALL 0-1
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cglobal checked_call%1, 2,15,16,max_args*8+8
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mov t0, r0
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; All arguments have been pushed on the stack instead of registers in order to
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; test for incorrect assumptions that 32-bit ints are zero-extended to 64-bit.
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mov r0, r6mp
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mov r1, r7mp
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mov r2, r8mp
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mov r3, r9mp
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%if UNIX64
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mov r4, r10mp
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mov r5, r11mp
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%assign i 6
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%rep max_args-6
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mov r9, [rsp+stack_offset+(i+1)*8]
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mov [rsp+(i-6)*8], r9
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%assign i i+1
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%endrep
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%else ; WIN64
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%assign i 4
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%rep max_args-4
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mov r9, [rsp+stack_offset+(i+7)*8]
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mov [rsp+i*8], r9
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%assign i i+1
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%endrep
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; Move possible floating-point arguments to the correct registers
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movq m0, r0
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movq m1, r1
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movq m2, r2
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movq m3, r3
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%assign i 6
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%rep 16-6
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mova m %+ i, [x %+ i]
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%assign i i+1
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%endrep
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%endif
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%assign i 14
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%rep 15-free_regs
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mov r %+ i, [n %+ i]
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%assign i i-1
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%endrep
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call t0
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%assign i 14
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%rep 15-free_regs
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xor r %+ i, [n %+ i]
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or r14, r %+ i
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%assign i i-1
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%endrep
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%if WIN64
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%assign i 6
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%rep 16-6
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pxor m %+ i, [x %+ i]
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por m6, m %+ i
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%assign i i+1
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%endrep
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packsswb m6, m6
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movq r5, m6
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or r14, r5
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%endif
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; Call fail_func() with a descriptive message to mark it as a failure
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; if the called function didn't preserve all callee-saved registers.
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; Save the return value located in rdx:rax first to prevent clobbering.
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jz .clobber_ok
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report_fail error_message
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.clobber_ok:
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%ifidn %1, _emms
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emms
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%elifnidn %1, _float
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fstenv [rsp]
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cmp word [rsp + 8], 0xffff
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je .emms_ok
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report_fail error_message_emms
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emms
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.emms_ok:
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%endif
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RET
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%endmacro
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%else
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; just random numbers to reduce the chance of incidental match
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%define n3 dword 0x6549315c
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%define n4 dword 0xe02f3e23
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%define n5 dword 0xb78d0d1d
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%define n6 dword 0x33627ba7
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%macro report_fail 1
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mov r3, eax
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mov r4, edx
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lea r0, [%1]
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mov [esp], r0
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call fail_func
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mov edx, r4
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mov eax, r3
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%endmacro
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%macro CHECKED_CALL 0-1
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;-----------------------------------------------------------------------------
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; void checkasm_checked_call(void *func, ...)
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;-----------------------------------------------------------------------------
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cglobal checked_call%1, 1,7
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mov r3, n3
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mov r4, n4
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mov r5, n5
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mov r6, n6
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%rep max_args
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PUSH dword [esp+20+max_args*4]
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%endrep
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call r0
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xor r3, n3
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xor r4, n4
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xor r5, n5
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xor r6, n6
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or r3, r4
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or r5, r6
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or r3, r5
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jz .clobber_ok
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report_fail error_message
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.clobber_ok:
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%ifidn %1, _emms
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emms
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%elifnidn %1, _float
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fstenv [esp]
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cmp word [esp + 8], 0xffff
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je .emms_ok
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report_fail error_message_emms
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emms
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.emms_ok:
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%endif
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add esp, max_args*4
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RET
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%endmacro
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%endif ; ARCH_X86_64
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CHECKED_CALL
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CHECKED_CALL _emms
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CHECKED_CALL _float
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