x86inc.asm

从服务器上下的x264编码器C源码……希望对大家有帮助……这个是09年4月的

;*****************************************************************************
;* x86inc.asm
;*****************************************************************************
;* Copyright (C) 2005-2008 x264 project
;*
;* Authors: Loren Merritt <[e-mail]>
;*          Anton Mitrofanov <[e-mail]>
;*
;* This program is free software; you can redistribute it and/or modify
;* it under the terms of the GNU General Public License as published by
;* the Free Software Foundation; either version 2 of the License, or
;* (at your option) any later version.
;*
;* This program is distributed in the hope that it will be useful,
;* but WITHOUT ANY WARRANTY; without even the implied warranty of
;* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;* GNU General Public License for more details.
;*
;* You should have received a copy of the GNU General Public License
;* along with this program; if not, write to the Free Software
;* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
;*****************************************************************************

%ifdef ARCH_X86_64
    %ifidn __OUTPUT_FORMAT__,win32
        %define WIN64
    %else
        %define UNIX64
    %endif
%endif

; FIXME: All of the 64bit asm functions that take a stride as an argument
; via register, assume that the high dword of that register is filled with 0.
; This is true in practice (since we never do any 64bit arithmetic on strides,
; and x264's strides are all positive), but is not guaranteed by the ABI.

; Name of the .rodata section.
; Kludge: Something on OS X fails to align .rodata even given an align attribute,
; so use a different read-only section.
%macro SECTION_RODATA 0
    %ifidn __OUTPUT_FORMAT__,macho64
        SECTION .text align=16
    %elifidn __OUTPUT_FORMAT__,macho
        SECTION .text align=16
        fakegot:
    %else
        SECTION .rodata align=16
    %endif
%endmacro

; PIC support macros.
; x86_64 can't fit 64bit address literals in most instruction types,
; so shared objects (under the assumption that they might be anywhere
; in memory) must use an address mode that does fit.
; So all accesses to global variables must use this macro, e.g.
;     mov eax, [foo GLOBAL]
; instead of
;     mov eax, [foo]
;
; x86_32 doesn't require PIC.
; Some distros prefer shared objects to be PIC, but nothing breaks if
; the code contains a few textrels, so we'll skip that complexity.

%ifdef WIN64
    %define PIC
%elifndef ARCH_X86_64
    %undef PIC
%endif
%ifdef PIC
    %define GLOBAL wrt rip
%else
    %define GLOBAL
%endif

; Macros to eliminate most code duplication between x86_32 and x86_64:
; Currently this works only for leaf functions which load all their arguments
; into registers at the start, and make no other use of the stack. Luckily that
; covers most of x264's asm.

; PROLOGUE:
; %1 = number of arguments. loads them from stack if needed.
; %2 = number of registers used. pushes callee-saved regs if needed.
; %3 = number of xmm registers used. pushes callee-saved xmm regs if needed.
; %4 = list of names to define to registers
; PROLOGUE can also be invoked by adding the same options to cglobal

; e.g.
; cglobal foo, 2,3, dst, src, tmp
; declares a function (foo), taking two args (dst and src) and one local variable (tmp)

; TODO Some functions can use some args directly from the stack. If they're the
; last args then you can just not declare them, but if they're in the middle
; we need more flexible macro.

; RET:
; Pops anything that was pushed by PROLOGUE

; REP_RET:
; Same, but if it doesn't pop anything it becomes a 2-byte ret, for athlons
; which are slow when a normal ret follows a branch.

; registers:
; rN and rNq are the native-size register holding function argument N
; rNd, rNw, rNb are dword, word, and byte size
; rNm is the original location of arg N (a register or on the stack), dword
; rNmp is native size

%macro DECLARE_REG 6
    %define r%1q %2
    %define r%1d %3
    %define r%1w %4
    %define r%1b %5
    %define r%1m %6
    %ifid %6 ; i.e. it's a register
        %define r%1mp %2
    %elifdef ARCH_X86_64 ; memory
        %define r%1mp qword %6
    %else
        %define r%1mp dword %6
    %endif
    %define r%1  %2
%endmacro

%macro DECLARE_REG_SIZE 2
    %define r%1q r%1
    %define e%1q r%1
    %define r%1d e%1
    %define e%1d e%1
    %define r%1w %1
    %define e%1w %1
    %define r%1b %2
    %define e%1b %2
%ifndef ARCH_X86_64
    %define r%1  e%1
%endif
%endmacro

DECLARE_REG_SIZE ax, al
DECLARE_REG_SIZE bx, bl
DECLARE_REG_SIZE cx, cl
DECLARE_REG_SIZE dx, dl
DECLARE_REG_SIZE si, sil
DECLARE_REG_SIZE di, dil
DECLARE_REG_SIZE bp, bpl

; t# defines for when per-arch register allocation is more complex than just function arguments

%macro DECLARE_REG_TMP 1-*
    %assign %%i 0
    %rep %0
        CAT_XDEFINE t, %%i, r%1
        %assign %%i %%i+1
        %rotate 1
    %endrep
%endmacro

%macro DECLARE_REG_TMP_SIZE 0-*
    %rep %0
        %define t%1q t%1 %+ q
        %define t%1d t%1 %+ d
        %define t%1w t%1 %+ w
        %define t%1b t%1 %+ b
        %rotate 1
    %endrep
%endmacro

DECLARE_REG_TMP_SIZE 0,1,2,3,4,5,6,7

%ifdef ARCH_X86_64
    %define gprsize 8
%else
    %define gprsize 4
%endif

%macro PUSH 1
    push %1
    %assign stack_offset stack_offset+gprsize
%endmacro

%macro POP 1
    pop %1
    %assign stack_offset stack_offset-gprsize
%endmacro

%macro SUB 2
    sub %1, %2
    %ifidn %1, rsp
        %assign stack_offset stack_offset+(%2)
    %endif
%endmacro

%macro ADD 2
    add %1, %2
    %ifidn %1, rsp
        %assign stack_offset stack_offset-(%2)
    %endif
%endmacro

%macro movifnidn 2
    %ifnidn %1, %2
        mov %1, %2
    %endif
%endmacro

%macro movsxdifnidn 2
    %ifnidn %1, %2
        movsxd %1, %2
    %endif
%endmacro

%macro ASSERT 1
    %if (%1) == 0
        %error assert failed
    %endif
%endmacro

%macro DEFINE_ARGS 0-*
    %ifdef n_arg_names
        %assign %%i 0
        %rep n_arg_names
            CAT_UNDEF arg_name %+ %%i, q
            CAT_UNDEF arg_name %+ %%i, d
            CAT_UNDEF arg_name %+ %%i, w
            CAT_UNDEF arg_name %+ %%i, b
            CAT_UNDEF arg_name, %%i
            %assign %%i %%i+1
        %endrep
    %endif

    %assign %%i 0
    %rep %0
        %xdefine %1q r %+ %%i %+ q
        %xdefine %1d r %+ %%i %+ d
        %xdefine %1w r %+ %%i %+ w
        %xdefine %1b r %+ %%i %+ b
        CAT_XDEFINE arg_name, %%i, %1
        %assign %%i %%i+1
        %rotate 1
    %endrep
    %assign n_arg_names %%i
%endmacro

%ifdef WIN64 ; Windows x64 ;=================================================

DECLARE_REG 0, rcx, ecx, cx,  cl,  ecx
DECLARE_REG 1, rdx, edx, dx,  dl,  edx
DECLARE_REG 2, r8,  r8d, r8w, r8b, r8d
DECLARE_REG 3, r9,  r9d, r9w, r9b, r9d
DECLARE_REG 4, rdi, edi, di,  dil, [rsp + stack_offset + 40]
DECLARE_REG 5, rsi, esi, si,  sil, [rsp + stack_offset + 48]
DECLARE_REG 6, rax, eax, ax,  al,  [rsp + stack_offset + 56]
%define r7m [rsp + stack_offset + 64]
%define r8m [rsp + stack_offset + 72]

%macro LOAD_IF_USED 2 ; reg_id, number_of_args
    %if %1 < %2
        mov r%1, [rsp + stack_offset + 8 + %1*8]
    %endif
%endmacro

%macro PROLOGUE 2-4+ ; #args, #regs, #xmm_regs, arg_names...
    ASSERT %2 >= %1
    %assign regs_used %2
    ASSERT regs_used <= 7
    %if %0 > 2
        %assign xmm_regs_used %3
    %else
        %assign xmm_regs_used 0
    %endif
    ASSERT xmm_regs_used <= 16
    %if regs_used > 4
        push r4
        push r5
        %assign stack_offset stack_offset+16
    %endif
    %if xmm_regs_used > 6
        sub rsp, (xmm_regs_used-6)*16+16
        %assign stack_offset stack_offset+(xmm_regs_used-6)*16+16
        %assign %%i xmm_regs_used
        %rep (xmm_regs_used-6)
            %assign %%i %%i-1
            movdqa [rsp + (%%i-6)*16+8], xmm %+ %%i
        %endrep
    %endif
    LOAD_IF_USED 4, %1
    LOAD_IF_USED 5, %1
    LOAD_IF_USED 6, %1
    DEFINE_ARGS %4
%endmacro

%macro RESTORE_XMM_INTERNAL 1
    %if xmm_regs_used > 6
        %assign %%i xmm_regs_used
        %rep (xmm_regs_used-6)
            %assign %%i %%i-1
            movdqa xmm %+ %%i, [%1 + (%%i-6)*16+8]
        %endrep
        add %1, (xmm_regs_used-6)*16+16
    %endif
%endmacro

%macro RESTORE_XMM 1
    RESTORE_XMM_INTERNAL %1
    %assign stack_offset stack_offset-(xmm_regs_used-6)*16+16
    %assign xmm_regs_used 0
%endmacro

%macro RET 0
    RESTORE_XMM_INTERNAL rsp
    %if regs_used > 4
        pop r5
        pop r4