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ffmpeg/libavcodec/i386/x86inc.asm
Jason Garrett-Glaser 40c7d0ae3c Add automatic prefix handling to yasm functions. Does nothing now, but will 
be useful for porting x264 asm in the future.

Originally committed as revision 16234 to svn://svn.ffmpeg.org/ffmpeg/trunk
2008-12-19 03:01:08 +00:00

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;*****************************************************************************
;* x86inc.asm
;*****************************************************************************
;* Copyright (C) 2005-2008 Loren Merritt <lorenm@u.washington.edu>
;*
;* This file is part of FFmpeg.
;*
;* FFmpeg is free software; you can redistribute it and/or
;* modify it under the terms of the GNU Lesser General Public
;* License as published by the Free Software Foundation; either
;* version 2.1 of the License, or (at your option) any later version.
;*
;* FFmpeg 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
;* Lesser General Public License for more details.
;*
;* You should have received a copy of the GNU Lesser General Public
;* License along with FFmpeg; if not, write to the Free Software
;* 51, Inc., Foundation Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;*****************************************************************************
; 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. All these macros are totally harmless when PIC is
; not defined but can ruin everything if misused in PIC mode. On x86_32, shared
; objects cannot directly access global variables by address, they need to
; go through the GOT (global offset table). Most OSes do not care about it
; and let you load non-shared .so objects (Linux, Win32...). However, OS X
; requires PIC code in its .dylib objects.
;
; - GLOBAL should be used as a suffix for global addressing, eg.
; picgetgot ebx
; mov eax, [foo GLOBAL]
; instead of
; mov eax, [foo]
;
; - picgetgot computes the GOT address into the given register in PIC
; mode, otherwise does nothing. You need to do this before using GLOBAL.
; Before in both execution order and compiled code order (so GLOBAL knows
; which register the GOT is in).
%ifndef PIC
%define GLOBAL
%macro picgetgot 1
%endmacro
%elifdef ARCH_X86_64
%define PIC64
%define GLOBAL wrt rip
%macro picgetgot 1
%endmacro
%else
%define PIC32
%ifidn __OUTPUT_FORMAT__,macho
; There is no real global offset table on OS X, but we still
; need to reference our variables by offset.
%macro picgetgot 1
call %%getgot
%%getgot:
pop %1
add %1, $$ - %%getgot
%undef GLOBAL
%define GLOBAL + %1 - fakegot
%endmacro
%else ; elf
extern _GLOBAL_OFFSET_TABLE_
%macro picgetgot 1
call %%getgot
%%getgot:
pop %1
add %1, _GLOBAL_OFFSET_TABLE_ + $$ - %%getgot wrt ..gotpc
%undef GLOBAL
%define GLOBAL + %1 wrt ..gotoff
%endmacro
%endif
%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, not including PIC. pushes callee-saved regs if needed.
; %3 = whether global constants are used in this function. inits x86_32 PIC 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, 2,3,0, dst, src, tmp
; declares a function (foo), taking two args (dst and src), one local variable (tmp), and not using globals
; 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.
%macro DECLARE_REG 6
%define r%1q %2
%define r%1d %3
%define r%1w %4
%define r%1b %5
%define r%1m %6
%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
%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 ARCH_X86_64 ;==========================================================
%ifidn __OUTPUT_FORMAT__,win32
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 + 8 + %1*8]
%endif
%endmacro
%else ;=======================================================================
DECLARE_REG 0, rdi, edi, di, dil, edi
DECLARE_REG 1, rsi, esi, si, sil, esi
DECLARE_REG 2, rdx, edx, dx, dl, edx
DECLARE_REG 3, rcx, ecx, cx, cl, ecx
DECLARE_REG 4, r8, r8d, r8w, r8b, r8d
DECLARE_REG 5, r9, r9d, r9w, r9b, r9d
DECLARE_REG 6, rax, eax, ax, al, [rsp + stack_offset + 8]
%define r7m [rsp + stack_offset + 16]
%define r8m [rsp + stack_offset + 24]
%macro LOAD_IF_USED 2 ; reg_id, number_of_args
%if %1 < %2
mov r%1, [rsp - 40 + %1*8]
%endif
%endmacro
%endif ; !WIN64
%macro PROLOGUE 2-4+ 0 ; #args, #regs, pic, arg_names...
ASSERT %2 >= %1
ASSERT %2 <= 7
%assign stack_offset 0
%ifidn __OUTPUT_FORMAT__,win32
LOAD_IF_USED 4, %1
LOAD_IF_USED 5, %1
%endif
LOAD_IF_USED 6, %1
DEFINE_ARGS %4
%endmacro
%macro RET 0
ret
%endmacro
%macro REP_RET 0
rep ret
%endmacro
%else ; X86_32 ;==============================================================
DECLARE_REG 0, eax, eax, ax, al, [esp + stack_offset + 4]
DECLARE_REG 1, ecx, ecx, cx, cl, [esp + stack_offset + 8]
DECLARE_REG 2, edx, edx, dx, dl, [esp + stack_offset + 12]
DECLARE_REG 3, ebx, ebx, bx, bl, [esp + stack_offset + 16]
DECLARE_REG 4, esi, esi, si, null, [esp + stack_offset + 20]
DECLARE_REG 5, edi, edi, di, null, [esp + stack_offset + 24]
DECLARE_REG 6, ebp, ebp, bp, null, [esp + stack_offset + 28]
%define r7m [esp + stack_offset + 32]
%define r8m [esp + stack_offset + 36]
%define rsp esp
%macro PUSH_IF_USED 1 ; reg_id
%if %1 < regs_used
push r%1
%assign stack_offset stack_offset+4
%endif
%endmacro
%macro POP_IF_USED 1 ; reg_id
%if %1 < regs_used
pop r%1
%endif
%endmacro
%macro LOAD_IF_USED 2 ; reg_id, number_of_args
%if %1 < %2
mov r%1, [esp + stack_offset + 4 + %1*4]
%endif
%endmacro
%macro PROLOGUE 2-4+ 0 ; #args, #regs, pic, arg_names...
ASSERT %2 >= %1
%assign stack_offset 0
%assign regs_used %2
%ifdef PIC
%if %3
%assign regs_used regs_used+1
%endif
%endif
ASSERT regs_used <= 7
PUSH_IF_USED 3
PUSH_IF_USED 4
PUSH_IF_USED 5
PUSH_IF_USED 6
LOAD_IF_USED 0, %1
LOAD_IF_USED 1, %1
LOAD_IF_USED 2, %1
LOAD_IF_USED 3, %1
LOAD_IF_USED 4, %1
LOAD_IF_USED 5, %1
LOAD_IF_USED 6, %1
%if %3
picgetgot r%2
%endif
DEFINE_ARGS %4
%endmacro
%macro RET 0
POP_IF_USED 6
POP_IF_USED 5
POP_IF_USED 4
POP_IF_USED 3
ret
%endmacro
%macro REP_RET 0
%if regs_used > 3
RET
%else
rep ret
%endif
%endmacro
%endif ;======================================================================
;=============================================================================
; arch-independent part
;=============================================================================
%assign function_align 16
; Symbol prefix for C linkage
%macro cglobal 1-2+
%xdefine %1 ff_%1
%ifdef PREFIX
%xdefine %1 _ %+ %1
%endif
%ifidn __OUTPUT_FORMAT__,elf
global %1:function hidden
%else
global %1
%endif
align function_align
%1:
RESET_MM_PERMUTATION ; not really needed, but makes disassembly somewhat nicer
%if %0 > 1
PROLOGUE %2
%endif
%endmacro
%macro cextern 1
%ifdef PREFIX
extern _%1
%define %1 _%1
%else
extern %1
%endif
%endmacro
; This is needed for ELF, otherwise the GNU linker assumes the stack is
; executable by default.
%ifidn __OUTPUT_FORMAT__,elf
SECTION .note.GNU-stack noalloc noexec nowrite progbits
%endif
%assign FENC_STRIDE 16
%assign FDEC_STRIDE 32
; merge mmx and sse*
%macro CAT_XDEFINE 3
%xdefine %1%2 %3
%endmacro
%macro CAT_UNDEF 2
%undef %1%2
%endmacro
%macro INIT_MMX 0
%define RESET_MM_PERMUTATION INIT_MMX
%define mmsize 8
%define num_mmregs 8
%define mova movq
%define movu movq
%define movh movd
%define movnt movntq
%assign %%i 0
%rep 8
CAT_XDEFINE m, %%i, mm %+ %%i
CAT_XDEFINE nmm, %%i, %%i
%assign %%i %%i+1
%endrep
%rep 8
CAT_UNDEF m, %%i
CAT_UNDEF nmm, %%i
%assign %%i %%i+1
%endrep
%endmacro
%macro INIT_XMM 0
%define RESET_MM_PERMUTATION INIT_XMM
%define mmsize 16
%define num_mmregs 8
%ifdef ARCH_X86_64
%define num_mmregs 16
%endif
%define mova movdqa
%define movu movdqu
%define movh movq
%define movnt movntdq
%assign %%i 0
%rep num_mmregs
CAT_XDEFINE m, %%i, xmm %+ %%i
CAT_XDEFINE nxmm, %%i, %%i
%assign %%i %%i+1
%endrep
%endmacro
INIT_MMX
; I often want to use macros that permute their arguments. e.g. there's no
; efficient way to implement butterfly or transpose or dct without swapping some
; arguments.
;
; I would like to not have to manually keep track of the permutations:
; If I insert a permutation in the middle of a function, it should automatically
; change everything that follows. For more complex macros I may also have multiple
; implementations, e.g. the SSE2 and SSSE3 versions may have different permutations.
;
; Hence these macros. Insert a PERMUTE or some SWAPs at the end of a macro that
; permutes its arguments. It's equivalent to exchanging the contents of the
; registers, except that this way you exchange the register names instead, so it
; doesn't cost any cycles.
%macro PERMUTE 2-* ; takes a list of pairs to swap
%rep %0/2
%xdefine tmp%2 m%2
%xdefine ntmp%2 nm%2
%rotate 2
%endrep
%rep %0/2
%xdefine m%1 tmp%2
%xdefine nm%1 ntmp%2
%undef tmp%2
%undef ntmp%2
%rotate 2
%endrep
%endmacro
%macro SWAP 2-* ; swaps a single chain (sometimes more concise than pairs)
%rep %0-1
%ifdef m%1
%xdefine tmp m%1
%xdefine m%1 m%2
%xdefine m%2 tmp
CAT_XDEFINE n, m%1, %1
CAT_XDEFINE n, m%2, %2
%else
; If we were called as "SWAP m0,m1" rather than "SWAP 0,1" infer the original numbers here.
; Be careful using this mode in nested macros though, as in some cases there may be
; other copies of m# that have already been dereferenced and don't get updated correctly.
%xdefine %%n1 n %+ %1
%xdefine %%n2 n %+ %2
%xdefine tmp m %+ %%n1
CAT_XDEFINE m, %%n1, m %+ %%n2
CAT_XDEFINE m, %%n2, tmp
CAT_XDEFINE n, m %+ %%n1, %%n1
CAT_XDEFINE n, m %+ %%n2, %%n2
%endif
%undef tmp
%rotate 1
%endrep
%endmacro
%macro SAVE_MM_PERMUTATION 1
%assign %%i 0
%rep num_mmregs
CAT_XDEFINE %1_m, %%i, m %+ %%i
%assign %%i %%i+1
%endrep
%endmacro
%macro LOAD_MM_PERMUTATION 1
%assign %%i 0
%rep num_mmregs
CAT_XDEFINE m, %%i, %1_m %+ %%i
%assign %%i %%i+1
%endrep
%endmacro
%macro call 1
call %1
%ifdef %1_m0
LOAD_MM_PERMUTATION %1
%endif
%endmacro
; substitutions which are functionally identical but reduce code size
%define movdqa movaps
%define movdqu movups
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