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1 bafad220 Loren Merritt
;*****************************************************************************
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;* x86inc.asm
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;*****************************************************************************
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;* Copyright (C) 2005-2008 Loren Merritt <lorenm@u.washington.edu>
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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
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;* modify it under the terms of the GNU Lesser General Public
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;* License as published by the Free Software Foundation; either
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;* version 2.1 of the License, or (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 GNU
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;* Lesser General Public License for more details.
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;*
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;* You should have received a copy of the GNU Lesser General Public
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;* License along with FFmpeg; if not, write to the Free Software
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;* 51, Inc., Foundation Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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;*****************************************************************************
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; FIXME: All of the 64bit asm functions that take a stride as an argument
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; via register, assume that the high dword of that register is filled with 0.
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; This is true in practice (since we never do any 64bit arithmetic on strides,
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; and x264's strides are all positive), but is not guaranteed by the ABI.
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; Name of the .rodata section.
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; Kludge: Something on OS X fails to align .rodata even given an align attribute,
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; so use a different read-only section.
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%macro SECTION_RODATA 0
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    %ifidn __OUTPUT_FORMAT__,macho64
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        SECTION .text align=16
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    %elifidn __OUTPUT_FORMAT__,macho
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        SECTION .text align=16
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        fakegot:
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    %else
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        SECTION .rodata align=16
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    %endif
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%endmacro
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; PIC support macros. All these macros are totally harmless when PIC is
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; not defined but can ruin everything if misused in PIC mode. On x86_32, shared
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; objects cannot directly access global variables by address, they need to
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; go through the GOT (global offset table). Most OSes do not care about it
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; and let you load non-shared .so objects (Linux, Win32...). However, OS X
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; requires PIC code in its .dylib objects.
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;
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; - GLOBAL should be used as a suffix for global addressing, eg.
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;     picgetgot ebx
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;     mov eax, [foo GLOBAL]
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;   instead of
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;     mov eax, [foo]
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;
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; - picgetgot computes the GOT address into the given register in PIC
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;   mode, otherwise does nothing. You need to do this before using GLOBAL.
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;   Before in both execution order and compiled code order (so GLOBAL knows
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;   which register the GOT is in).
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%ifndef PIC
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    %define GLOBAL
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    %macro picgetgot 1
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    %endmacro
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%elifdef ARCH_X86_64
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    %define PIC64
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    %define GLOBAL wrt rip
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    %macro picgetgot 1
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    %endmacro
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%else
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    %define PIC32
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    %ifidn __OUTPUT_FORMAT__,macho
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        ; There is no real global offset table on OS X, but we still
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        ; need to reference our variables by offset.
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        %macro picgetgot 1
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            call %%getgot
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          %%getgot:
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            pop %1
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            add %1, $$ - %%getgot
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            %undef GLOBAL
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            %define GLOBAL + %1 - fakegot
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        %endmacro
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    %else ; elf
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        extern _GLOBAL_OFFSET_TABLE_
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        %macro picgetgot 1
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            call %%getgot
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          %%getgot:
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            pop %1
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            add %1, _GLOBAL_OFFSET_TABLE_ + $$ - %%getgot wrt ..gotpc
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            %undef GLOBAL
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            %define GLOBAL + %1 wrt ..gotoff
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        %endmacro
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    %endif
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%endif
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; Macros to eliminate most code duplication between x86_32 and x86_64:
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; Currently this works only for leaf functions which load all their arguments
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; into registers at the start, and make no other use of the stack. Luckily that
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; covers most of x264's asm.
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; PROLOGUE:
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; %1 = number of arguments. loads them from stack if needed.
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; %2 = number of registers used, not including PIC. pushes callee-saved regs if needed.
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; %3 = whether global constants are used in this function. inits x86_32 PIC if needed.
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; %4 = list of names to define to registers
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; PROLOGUE can also be invoked by adding the same options to cglobal
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; e.g.
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; cglobal foo, 2,3,0, dst, src, tmp
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; declares a function (foo), taking two args (dst and src), one local variable (tmp), and not using globals
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; TODO Some functions can use some args directly from the stack. If they're the
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; last args then you can just not declare them, but if they're in the middle
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; we need more flexible macro.
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; RET:
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; Pops anything that was pushed by PROLOGUE
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; REP_RET:
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; Same, but if it doesn't pop anything it becomes a 2-byte ret, for athlons
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; which are slow when a normal ret follows a branch.
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%macro DECLARE_REG 6
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    %define r%1q %2
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    %define r%1d %3
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    %define r%1w %4
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    %define r%1b %5
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    %define r%1m %6
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    %define r%1  %2
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%endmacro
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%macro DECLARE_REG_SIZE 2
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    %define r%1q r%1
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    %define e%1q r%1
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    %define r%1d e%1
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    %define e%1d e%1
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    %define r%1w %1
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    %define e%1w %1
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    %define r%1b %2
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    %define e%1b %2
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%ifndef ARCH_X86_64
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    %define r%1  e%1
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%endif
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%endmacro
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DECLARE_REG_SIZE ax, al
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DECLARE_REG_SIZE bx, bl
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DECLARE_REG_SIZE cx, cl
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DECLARE_REG_SIZE dx, dl
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DECLARE_REG_SIZE si, sil
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DECLARE_REG_SIZE di, dil
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DECLARE_REG_SIZE bp, bpl
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%ifdef ARCH_X86_64
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    %define gprsize 8
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%else
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    %define gprsize 4
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%endif
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%macro PUSH 1
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    push %1
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    %assign stack_offset stack_offset+gprsize
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%endmacro
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%macro POP 1
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    pop %1
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    %assign stack_offset stack_offset-gprsize
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%endmacro
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%macro SUB 2
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    sub %1, %2
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    %ifidn %1, rsp
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        %assign stack_offset stack_offset+(%2)
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    %endif
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%endmacro
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%macro ADD 2
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    add %1, %2
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    %ifidn %1, rsp
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        %assign stack_offset stack_offset-(%2)
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    %endif
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%endmacro
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%macro movifnidn 2
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    %ifnidn %1, %2
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        mov %1, %2
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    %endif
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%endmacro
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%macro movsxdifnidn 2
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    %ifnidn %1, %2
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        movsxd %1, %2
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    %endif
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%endmacro
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%macro ASSERT 1
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    %if (%1) == 0
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        %error assert failed
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    %endif
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%endmacro
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%macro DEFINE_ARGS 0-*
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    %ifdef n_arg_names
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        %assign %%i 0
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        %rep n_arg_names
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            CAT_UNDEF arg_name %+ %%i, q
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            CAT_UNDEF arg_name %+ %%i, d
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            CAT_UNDEF arg_name %+ %%i, w
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            CAT_UNDEF arg_name %+ %%i, b
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            CAT_UNDEF arg_name, %%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 0
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    %rep %0
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        %xdefine %1q r %+ %%i %+ q
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        %xdefine %1d r %+ %%i %+ d
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        %xdefine %1w r %+ %%i %+ w
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        %xdefine %1b r %+ %%i %+ b
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        CAT_XDEFINE arg_name, %%i, %1
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        %assign %%i %%i+1
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        %rotate 1
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    %endrep
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    %assign n_arg_names %%i
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%endmacro
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%ifdef ARCH_X86_64 ;==========================================================
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%ifidn __OUTPUT_FORMAT__,win32
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DECLARE_REG 0, rcx, ecx, cx,  cl,  ecx
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DECLARE_REG 1, rdx, edx, dx,  dl,  edx
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DECLARE_REG 2, r8,  r8d, r8w, r8b, r8d
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DECLARE_REG 3, r9,  r9d, r9w, r9b, r9d
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DECLARE_REG 4, rdi, edi, di,  dil, [rsp + stack_offset + 40]
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DECLARE_REG 5, rsi, esi, si,  sil, [rsp + stack_offset + 48]
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DECLARE_REG 6, rax, eax, ax,  al,  [rsp + stack_offset + 56]
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%define r7m [rsp + stack_offset + 64]
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%define r8m [rsp + stack_offset + 72]
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%macro LOAD_IF_USED 2 ; reg_id, number_of_args
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    %if %1 < %2
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        mov r%1, [rsp + 8 + %1*8]
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    %endif
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%endmacro
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%else ;=======================================================================
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DECLARE_REG 0, rdi, edi, di,  dil, edi
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DECLARE_REG 1, rsi, esi, si,  sil, esi
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DECLARE_REG 2, rdx, edx, dx,  dl,  edx
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DECLARE_REG 3, rcx, ecx, cx,  cl,  ecx
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DECLARE_REG 4, r8,  r8d, r8w, r8b, r8d
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DECLARE_REG 5, r9,  r9d, r9w, r9b, r9d
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DECLARE_REG 6, rax, eax, ax,  al,  [rsp + stack_offset + 8]
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%define r7m [rsp + stack_offset + 16]
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%define r8m [rsp + stack_offset + 24]
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%macro LOAD_IF_USED 2 ; reg_id, number_of_args
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    %if %1 < %2
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        mov r%1, [rsp - 40 + %1*8]
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    %endif
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%endmacro
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%endif ; !WIN64
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%macro PROLOGUE 2-4+ 0 ; #args, #regs, pic, arg_names...
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    ASSERT %2 >= %1
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    ASSERT %2 <= 7
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    %assign stack_offset 0
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%ifidn __OUTPUT_FORMAT__,win32
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    LOAD_IF_USED 4, %1
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    LOAD_IF_USED 5, %1
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%endif
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    LOAD_IF_USED 6, %1
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    DEFINE_ARGS %4
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%endmacro
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%macro RET 0
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    ret
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%endmacro
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%macro REP_RET 0
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    rep ret
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%endmacro
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%else ; X86_32 ;==============================================================
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DECLARE_REG 0, eax, eax, ax, al,   [esp + stack_offset + 4]
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DECLARE_REG 1, ecx, ecx, cx, cl,   [esp + stack_offset + 8]
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DECLARE_REG 2, edx, edx, dx, dl,   [esp + stack_offset + 12]
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DECLARE_REG 3, ebx, ebx, bx, bl,   [esp + stack_offset + 16]
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DECLARE_REG 4, esi, esi, si, null, [esp + stack_offset + 20]
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DECLARE_REG 5, edi, edi, di, null, [esp + stack_offset + 24]
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DECLARE_REG 6, ebp, ebp, bp, null, [esp + stack_offset + 28]
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%define r7m [esp + stack_offset + 32]
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%define r8m [esp + stack_offset + 36]
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%define rsp esp
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%macro PUSH_IF_USED 1 ; reg_id
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    %if %1 < regs_used
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        push r%1
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        %assign stack_offset stack_offset+4
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    %endif
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%endmacro
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%macro POP_IF_USED 1 ; reg_id
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    %if %1 < regs_used
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        pop r%1
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    %endif
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%endmacro
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%macro LOAD_IF_USED 2 ; reg_id, number_of_args
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    %if %1 < %2
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        mov r%1, [esp + stack_offset + 4 + %1*4]
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    %endif
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%endmacro
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%macro PROLOGUE 2-4+ 0 ; #args, #regs, pic, arg_names...
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    ASSERT %2 >= %1
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    %assign stack_offset 0
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    %assign regs_used %2
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    %ifdef PIC
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    %if %3
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        %assign regs_used regs_used+1
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    %endif
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    %endif
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    ASSERT regs_used <= 7
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    PUSH_IF_USED 3
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    PUSH_IF_USED 4
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    PUSH_IF_USED 5
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    PUSH_IF_USED 6
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    LOAD_IF_USED 0, %1
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    LOAD_IF_USED 1, %1
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    LOAD_IF_USED 2, %1
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    LOAD_IF_USED 3, %1
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    LOAD_IF_USED 4, %1
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    LOAD_IF_USED 5, %1
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    LOAD_IF_USED 6, %1
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    %if %3
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        picgetgot r%2
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    %endif
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    DEFINE_ARGS %4
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%endmacro
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%macro RET 0
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    POP_IF_USED 6
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    POP_IF_USED 5
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    POP_IF_USED 4
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    POP_IF_USED 3
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    ret
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%endmacro
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%macro REP_RET 0
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    %if regs_used > 3
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        RET
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    %else
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        rep ret
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    %endif
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%endmacro
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%endif ;======================================================================
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;=============================================================================
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; arch-independent part
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;=============================================================================
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%assign function_align 16
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; Symbol prefix for C linkage
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%macro cglobal 1-2+
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    %xdefine %1 ff_%1
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    %ifdef PREFIX
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        %xdefine %1 _ %+ %1
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    %endif
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    %ifidn __OUTPUT_FORMAT__,elf
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        global %1:function hidden
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    %else
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        global %1
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    %endif
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    align function_align
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    %1:
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    RESET_MM_PERMUTATION ; not really needed, but makes disassembly somewhat nicer
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    %if %0 > 1
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        PROLOGUE %2
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    %endif
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%endmacro
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%macro cextern 1
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    %ifdef PREFIX
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        extern _%1
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        %define %1 _%1
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    %else
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        extern %1
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    %endif
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%endmacro
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; This is needed for ELF, otherwise the GNU linker assumes the stack is
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; executable by default.
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%ifidn __OUTPUT_FORMAT__,elf
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SECTION .note.GNU-stack noalloc noexec nowrite progbits
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%endif
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%assign FENC_STRIDE 16
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%assign FDEC_STRIDE 32
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; merge mmx and sse*
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%macro CAT_XDEFINE 3
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    %xdefine %1%2 %3
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%endmacro
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%macro CAT_UNDEF 2
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    %undef %1%2
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%endmacro
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%macro INIT_MMX 0
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    %define RESET_MM_PERMUTATION INIT_MMX
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    %define mmsize 8
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    %define num_mmregs 8
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    %define mova movq
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    %define movu movq
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    %define movh movd
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    %define movnt movntq
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    %assign %%i 0
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    %rep 8
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    CAT_XDEFINE m, %%i, mm %+ %%i
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    CAT_XDEFINE nmm, %%i, %%i
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    %assign %%i %%i+1
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    %endrep
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    %rep 8
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    CAT_UNDEF m, %%i
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    CAT_UNDEF nmm, %%i
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    %assign %%i %%i+1
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    %endrep
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%endmacro
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%macro INIT_XMM 0
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    %define RESET_MM_PERMUTATION INIT_XMM
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    %define mmsize 16
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    %define num_mmregs 8
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    %ifdef ARCH_X86_64
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    %define num_mmregs 16
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    %endif
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    %define mova movdqa
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    %define movu movdqu
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    %define movh movq
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    %define movnt movntdq
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    %assign %%i 0
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    %rep num_mmregs
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    CAT_XDEFINE m, %%i, xmm %+ %%i
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    CAT_XDEFINE nxmm, %%i, %%i
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    %assign %%i %%i+1
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    %endrep
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%endmacro
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INIT_MMX
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; I often want to use macros that permute their arguments. e.g. there's no
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; efficient way to implement butterfly or transpose or dct without swapping some
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; arguments.
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;
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; I would like to not have to manually keep track of the permutations:
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; If I insert a permutation in the middle of a function, it should automatically
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; change everything that follows. For more complex macros I may also have multiple
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; implementations, e.g. the SSE2 and SSSE3 versions may have different permutations.
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;
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; Hence these macros. Insert a PERMUTE or some SWAPs at the end of a macro that
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; permutes its arguments. It's equivalent to exchanging the contents of the
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; registers, except that this way you exchange the register names instead, so it
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; doesn't cost any cycles.
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%macro PERMUTE 2-* ; takes a list of pairs to swap
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%rep %0/2
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    %xdefine tmp%2 m%2
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    %xdefine ntmp%2 nm%2
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    %rotate 2
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%endrep
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%rep %0/2
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    %xdefine m%1 tmp%2
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    %xdefine nm%1 ntmp%2
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    %undef tmp%2
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    %undef ntmp%2
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    %rotate 2
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%endrep
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%endmacro
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%macro SWAP 2-* ; swaps a single chain (sometimes more concise than pairs)
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%rep %0-1
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%ifdef m%1
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    %xdefine tmp m%1
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    %xdefine m%1 m%2
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    %xdefine m%2 tmp
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    CAT_XDEFINE n, m%1, %1
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    CAT_XDEFINE n, m%2, %2
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%else
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    ; If we were called as "SWAP m0,m1" rather than "SWAP 0,1" infer the original numbers here.
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    ; Be careful using this mode in nested macros though, as in some cases there may be
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    ; other copies of m# that have already been dereferenced and don't get updated correctly.
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    %xdefine %%n1 n %+ %1
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    %xdefine %%n2 n %+ %2
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    %xdefine tmp m %+ %%n1
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    CAT_XDEFINE m, %%n1, m %+ %%n2
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    CAT_XDEFINE m, %%n2, tmp
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    CAT_XDEFINE n, m %+ %%n1, %%n1
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    CAT_XDEFINE n, m %+ %%n2, %%n2
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%endif
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    %undef tmp
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    %rotate 1
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%endrep
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%endmacro
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%macro SAVE_MM_PERMUTATION 1
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    %assign %%i 0
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    %rep num_mmregs
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    CAT_XDEFINE %1_m, %%i, m %+ %%i
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    %assign %%i %%i+1
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    %endrep
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%endmacro
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%macro LOAD_MM_PERMUTATION 1
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    %assign %%i 0
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    %rep num_mmregs
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    CAT_XDEFINE m, %%i, %1_m %+ %%i
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    %assign %%i %%i+1
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    %endrep
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%endmacro
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%macro call 1
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    call %1
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    %ifdef %1_m0
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        LOAD_MM_PERMUTATION %1
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    %endif
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%endmacro
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; substitutions which are functionally identical but reduce code size
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%define movdqa movaps
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%define movdqu movups