libavcodec/x86/x86inc.asm

   1 ;*****************************************************************************
   2 ;* x86inc.asm
   3 ;*****************************************************************************
   4 ;* Copyright (C) 2005-2008 Loren Merritt <lorenm@u.washington.edu>
   5 ;*
   6 ;* This file is part of FFmpeg.
   7 ;*
   8 ;* FFmpeg is free software; you can redistribute it and/or
   9 ;* modify it under the terms of the GNU Lesser General Public
  10 ;* License as published by the Free Software Foundation; either
  11 ;* version 2.1 of the License, or (at your option) any later version.
  12 ;*
  13 ;* FFmpeg is distributed in the hope that it will be useful,
  14 ;* but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 ;* Lesser General Public License for more details.
  17 ;*
  18 ;* You should have received a copy of the GNU Lesser General Public
  19 ;* License along with FFmpeg; if not, write to the Free Software
  20 ;* 51, Inc., Foundation Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21 ;*****************************************************************************
  22
  23 ; FIXME: All of the 64bit asm functions that take a stride as an argument
  24 ; via register, assume that the high dword of that register is filled with 0.
  25 ; This is true in practice (since we never do any 64bit arithmetic on strides,
  26 ; and x264's strides are all positive), but is not guaranteed by the ABI.
  27
  28 ; Name of the .rodata section.
  29 ; Kludge: Something on OS X fails to align .rodata even given an align attribute,
  30 ; so use a different read-only section.
  31 %macro SECTION_RODATA 0
  32     %ifidn __OUTPUT_FORMAT__,macho64
  33         SECTION .text align=16
  34     %elifidn __OUTPUT_FORMAT__,macho
  35         SECTION .text align=16
  36         fakegot:
  37     %else
  38         SECTION .rodata align=16
  39     %endif
  40 %endmacro
  41
  42 ; PIC support macros. All these macros are totally harmless when PIC is
  43 ; not defined but can ruin everything if misused in PIC mode. On x86_32, shared
  44 ; objects cannot directly access global variables by address, they need to
  45 ; go through the GOT (global offset table). Most OSes do not care about it
  46 ; and let you load non-shared .so objects (Linux, Win32...). However, OS X
  47 ; requires PIC code in its .dylib objects.
  48 ;
  49 ; - GLOBAL should be used as a suffix for global addressing, eg.
  50 ;     picgetgot ebx
  51 ;     mov eax, [foo GLOBAL]
  52 ;   instead of
  53 ;     mov eax, [foo]
  54 ;
  55 ; - picgetgot computes the GOT address into the given register in PIC
  56 ;   mode, otherwise does nothing. You need to do this before using GLOBAL.
  57 ;   Before in both execution order and compiled code order (so GLOBAL knows
  58 ;   which register the GOT is in).
  59
  60 %ifndef PIC
  61     %define GLOBAL
  62     %macro picgetgot 1
  63     %endmacro
  64 %elifdef ARCH_X86_64
  65     %define PIC64
  66     %define GLOBAL wrt rip
  67     %macro picgetgot 1
  68     %endmacro
  69 %else
  70     %define PIC32
  71     %ifidn __OUTPUT_FORMAT__,macho
  72         ; There is no real global offset table on OS X, but we still
  73         ; need to reference our variables by offset.
  74         %macro picgetgot 1
  75             call %%getgot
  76           %%getgot:
  77             pop %1
  78             add %1, $$ - %%getgot
  79             %undef GLOBAL
  80             %define GLOBAL + %1 - fakegot
  81         %endmacro
  82     %else ; elf
  83         extern _GLOBAL_OFFSET_TABLE_
  84         %macro picgetgot 1
  85             call %%getgot
  86           %%getgot:
  87             pop %1
  88             add %1, _GLOBAL_OFFSET_TABLE_ + $$ - %%getgot wrt ..gotpc
  89             %undef GLOBAL
  90             %define GLOBAL + %1 wrt ..gotoff
  91         %endmacro
  92     %endif
  93 %endif
  94
  95 ; Macros to eliminate most code duplication between x86_32 and x86_64:
  96 ; Currently this works only for leaf functions which load all their arguments
  97 ; into registers at the start, and make no other use of the stack. Luckily that
  98 ; covers most of x264's asm.
  99
 100 ; PROLOGUE:
 101 ; %1 = number of arguments. loads them from stack if needed.
 102 ; %2 = number of registers used, not including PIC. pushes callee-saved regs if needed.
 103 ; %3 = whether global constants are used in this function. inits x86_32 PIC if needed.
 104 ; %4 = list of names to define to registers
 105 ; PROLOGUE can also be invoked by adding the same options to cglobal
 106
 107 ; e.g.
 108 ; cglobal foo, 2,3,0, dst, src, tmp
 109 ; declares a function (foo), taking two args (dst and src), one local variable (tmp), and not using globals
 110
 111 ; TODO Some functions can use some args directly from the stack. If they're the
 112 ; last args then you can just not declare them, but if they're in the middle
 113 ; we need more flexible macro.
 114
 115 ; RET:
 116 ; Pops anything that was pushed by PROLOGUE
 117
 118 ; REP_RET:
 119 ; Same, but if it doesn't pop anything it becomes a 2-byte ret, for athlons
 120 ; which are slow when a normal ret follows a branch.
 121
 122 %macro DECLARE_REG 6
 123     %define r%1q %2
 124     %define r%1d %3
 125     %define r%1w %4
 126     %define r%1b %5
 127     %define r%1m %6
 128     %define r%1  %2
 129 %endmacro
 130
 131 %macro DECLARE_REG_SIZE 2
 132     %define r%1q r%1
 133     %define e%1q r%1
 134     %define r%1d e%1
 135     %define e%1d e%1
 136     %define r%1w %1
 137     %define e%1w %1
 138     %define r%1b %2
 139     %define e%1b %2
 140 %ifndef ARCH_X86_64
 141     %define r%1  e%1
 142 %endif
 143 %endmacro
 144
 145 DECLARE_REG_SIZE ax, al
 146 DECLARE_REG_SIZE bx, bl
 147 DECLARE_REG_SIZE cx, cl
 148 DECLARE_REG_SIZE dx, dl
 149 DECLARE_REG_SIZE si, sil
 150 DECLARE_REG_SIZE di, dil
 151 DECLARE_REG_SIZE bp, bpl
 152
 153 %ifdef ARCH_X86_64
 154     %define gprsize 8
 155 %else
 156     %define gprsize 4
 157 %endif
 158
 159 %macro PUSH 1
 160     push %1
 161     %assign stack_offset stack_offset+gprsize
 162 %endmacro
 163
 164 %macro POP 1
 165     pop %1
 166     %assign stack_offset stack_offset-gprsize
 167 %endmacro
 168
 169 %macro SUB 2
 170     sub %1, %2
 171     %ifidn %1, rsp
 172         %assign stack_offset stack_offset+(%2)
 173     %endif
 174 %endmacro
 175
 176 %macro ADD 2
 177     add %1, %2
 178     %ifidn %1, rsp
 179         %assign stack_offset stack_offset-(%2)
 180     %endif
 181 %endmacro
 182
 183 %macro movifnidn 2
 184     %ifnidn %1, %2
 185         mov %1, %2
 186     %endif
 187 %endmacro
 188
 189 %macro movsxdifnidn 2
 190     %ifnidn %1, %2
 191         movsxd %1, %2
 192     %endif
 193 %endmacro
 194
 195 %macro ASSERT 1
 196     %if (%1) == 0
 197         %error assert failed
 198     %endif
 199 %endmacro
 200
 201 %macro DEFINE_ARGS 0-*
 202     %ifdef n_arg_names
 203         %assign %%i 0
 204         %rep n_arg_names
 205             CAT_UNDEF arg_name %+ %%i, q
 206             CAT_UNDEF arg_name %+ %%i, d
 207             CAT_UNDEF arg_name %+ %%i, w
 208             CAT_UNDEF arg_name %+ %%i, b
 209             CAT_UNDEF arg_name, %%i
 210             %assign %%i %%i+1
 211         %endrep
 212     %endif
 213
 214     %assign %%i 0
 215     %rep %0
 216         %xdefine %1q r %+ %%i %+ q
 217         %xdefine %1d r %+ %%i %+ d
 218         %xdefine %1w r %+ %%i %+ w
 219         %xdefine %1b r %+ %%i %+ b
 220         CAT_XDEFINE arg_name, %%i, %1
 221         %assign %%i %%i+1
 222         %rotate 1
 223     %endrep
 224     %assign n_arg_names %%i
 225 %endmacro
 226
 227 %ifdef ARCH_X86_64 ;==========================================================
 228 %ifidn __OUTPUT_FORMAT__,win32
 229
 230 DECLARE_REG 0, rcx, ecx, cx,  cl,  ecx
 231 DECLARE_REG 1, rdx, edx, dx,  dl,  edx
 232 DECLARE_REG 2, r8,  r8d, r8w, r8b, r8d
 233 DECLARE_REG 3, r9,  r9d, r9w, r9b, r9d
 234 DECLARE_REG 4, rdi, edi, di,  dil, [rsp + stack_offset + 40]
 235 DECLARE_REG 5, rsi, esi, si,  sil, [rsp + stack_offset + 48]
 236 DECLARE_REG 6, rax, eax, ax,  al,  [rsp + stack_offset + 56]
 237 %define r7m [rsp + stack_offset + 64]
 238 %define r8m [rsp + stack_offset + 72]
 239
 240 %macro LOAD_IF_USED 2 ; reg_id, number_of_args
 241     %if %1 < %2
 242         mov r%1, [rsp + 8 + %1*8]
 243     %endif
 244 %endmacro
 245
 246 %else ;=======================================================================
 247
 248 DECLARE_REG 0, rdi, edi, di,  dil, edi
 249 DECLARE_REG 1, rsi, esi, si,  sil, esi
 250 DECLARE_REG 2, rdx, edx, dx,  dl,  edx
 251 DECLARE_REG 3, rcx, ecx, cx,  cl,  ecx
 252 DECLARE_REG 4, r8,  r8d, r8w, r8b, r8d
 253 DECLARE_REG 5, r9,  r9d, r9w, r9b, r9d
 254 DECLARE_REG 6, rax, eax, ax,  al,  [rsp + stack_offset + 8]
 255 %define r7m [rsp + stack_offset + 16]
 256 %define r8m [rsp + stack_offset + 24]
 257
 258 %macro LOAD_IF_USED 2 ; reg_id, number_of_args
 259     %if %1 < %2
 260         mov r%1, [rsp - 40 + %1*8]
 261     %endif
 262 %endmacro
 263
 264 %endif ; !WIN64
 265
 266 %macro PROLOGUE 2-4+ 0 ; #args, #regs, pic, arg_names...
 267     ASSERT %2 >= %1
 268     ASSERT %2 <= 7
 269     %assign stack_offset 0
 270 %ifidn __OUTPUT_FORMAT__,win32
 271     LOAD_IF_USED 4, %1
 272     LOAD_IF_USED 5, %1
 273 %endif
 274     LOAD_IF_USED 6, %1
 275     DEFINE_ARGS %4
 276 %endmacro
 277
 278 %macro RET 0
 279     ret
 280 %endmacro
 281
 282 %macro REP_RET 0
 283     rep ret
 284 %endmacro
 285
 286 %else ; X86_32 ;==============================================================
 287
 288 DECLARE_REG 0, eax, eax, ax, al,   [esp + stack_offset + 4]
 289 DECLARE_REG 1, ecx, ecx, cx, cl,   [esp + stack_offset + 8]
 290 DECLARE_REG 2, edx, edx, dx, dl,   [esp + stack_offset + 12]
 291 DECLARE_REG 3, ebx, ebx, bx, bl,   [esp + stack_offset + 16]
 292 DECLARE_REG 4, esi, esi, si, null, [esp + stack_offset + 20]
 293 DECLARE_REG 5, edi, edi, di, null, [esp + stack_offset + 24]
 294 DECLARE_REG 6, ebp, ebp, bp, null, [esp + stack_offset + 28]
 295 %define r7m [esp + stack_offset + 32]
 296 %define r8m [esp + stack_offset + 36]
 297 %define rsp esp
 298
 299 %macro PUSH_IF_USED 1 ; reg_id
 300     %if %1 < regs_used
 301         push r%1
 302         %assign stack_offset stack_offset+4
 303     %endif
 304 %endmacro
 305
 306 %macro POP_IF_USED 1 ; reg_id
 307     %if %1 < regs_used
 308         pop r%1
 309     %endif
 310 %endmacro
 311
 312 %macro LOAD_IF_USED 2 ; reg_id, number_of_args
 313     %if %1 < %2
 314         mov r%1, [esp + stack_offset + 4 + %1*4]
 315     %endif
 316 %endmacro
 317
 318 %macro PROLOGUE 2-4+ 0 ; #args, #regs, pic, arg_names...
 319     ASSERT %2 >= %1
 320     %assign stack_offset 0
 321     %assign regs_used %2
 322     %ifdef PIC
 323     %if %3
 324         %assign regs_used regs_used+1
 325     %endif
 326     %endif
 327     ASSERT regs_used <= 7
 328     PUSH_IF_USED 3
 329     PUSH_IF_USED 4
 330     PUSH_IF_USED 5
 331     PUSH_IF_USED 6
 332     LOAD_IF_USED 0, %1
 333     LOAD_IF_USED 1, %1
 334     LOAD_IF_USED 2, %1
 335     LOAD_IF_USED 3, %1
 336     LOAD_IF_USED 4, %1
 337     LOAD_IF_USED 5, %1
 338     LOAD_IF_USED 6, %1
 339     %if %3
 340         picgetgot r%2
 341     %endif
 342     DEFINE_ARGS %4
 343 %endmacro
 344
 345 %macro RET 0
 346     POP_IF_USED 6
 347     POP_IF_USED 5
 348     POP_IF_USED 4
 349     POP_IF_USED 3
 350     ret
 351 %endmacro
 352
 353 %macro REP_RET 0
 354     %if regs_used > 3
 355         RET
 356     %else
 357         rep ret
 358     %endif
 359 %endmacro
 360
 361 %endif ;======================================================================
 362
 363
 364
 365 ;=============================================================================
 366 ; arch-independent part
 367 ;=============================================================================
 368
 369 %assign function_align 16
 370
 371 ; Symbol prefix for C linkage
 372 %macro cglobal 1-2+
 373     %xdefine %1 ff_%1
 374     %ifdef PREFIX
 375         %xdefine %1 _ %+ %1
 376     %endif
 377     %ifidn __OUTPUT_FORMAT__,elf
 378         global %1:function hidden
 379     %else
 380         global %1
 381     %endif
 382     align function_align
 383     %1:
 384     RESET_MM_PERMUTATION ; not really needed, but makes disassembly somewhat nicer
 385     %if %0 > 1
 386         PROLOGUE %2
 387     %endif
 388 %endmacro
 389
 390 %macro cextern 1
 391     %ifdef PREFIX
 392         extern _%1
 393         %define %1 _%1
 394     %else
 395         extern %1
 396     %endif
 397 %endmacro
 398
 399 ; This is needed for ELF, otherwise the GNU linker assumes the stack is
 400 ; executable by default.
 401 %ifidn __OUTPUT_FORMAT__,elf
 402 SECTION .note.GNU-stack noalloc noexec nowrite progbits
 403 %endif
 404
 405 %assign FENC_STRIDE 16
 406 %assign FDEC_STRIDE 32
 407
 408 ; merge mmx and sse*
 409
 410 %macro CAT_XDEFINE 3
 411     %xdefine %1%2 %3
 412 %endmacro
 413
 414 %macro CAT_UNDEF 2
 415     %undef %1%2
 416 %endmacro
 417
 418 %macro INIT_MMX 0
 419     %define RESET_MM_PERMUTATION INIT_MMX
 420     %define mmsize 8
 421     %define num_mmregs 8
 422     %define mova movq
 423     %define movu movq
 424     %define movh movd
 425     %define movnt movntq
 426     %assign %%i 0
 427     %rep 8
 428     CAT_XDEFINE m, %%i, mm %+ %%i
 429     CAT_XDEFINE nmm, %%i, %%i
 430     %assign %%i %%i+1
 431     %endrep
 432     %rep 8
 433     CAT_UNDEF m, %%i
 434     CAT_UNDEF nmm, %%i
 435     %assign %%i %%i+1
 436     %endrep
 437 %endmacro
 438
 439 %macro INIT_XMM 0
 440     %define RESET_MM_PERMUTATION INIT_XMM
 441     %define mmsize 16
 442     %define num_mmregs 8
 443     %ifdef ARCH_X86_64
 444     %define num_mmregs 16
 445     %endif
 446     %define mova movdqa
 447     %define movu movdqu
 448     %define movh movq
 449     %define movnt movntdq
 450     %assign %%i 0
 451     %rep num_mmregs
 452     CAT_XDEFINE m, %%i, xmm %+ %%i
 453     CAT_XDEFINE nxmm, %%i, %%i
 454     %assign %%i %%i+1
 455     %endrep
 456 %endmacro
 457
 458 INIT_MMX
 459
 460 ; I often want to use macros that permute their arguments. e.g. there's no
 461 ; efficient way to implement butterfly or transpose or dct without swapping some
 462 ; arguments.
 463 ;
 464 ; I would like to not have to manually keep track of the permutations:
 465 ; If I insert a permutation in the middle of a function, it should automatically
 466 ; change everything that follows. For more complex macros I may also have multiple
 467 ; implementations, e.g. the SSE2 and SSSE3 versions may have different permutations.
 468 ;
 469 ; Hence these macros. Insert a PERMUTE or some SWAPs at the end of a macro that
 470 ; permutes its arguments. It's equivalent to exchanging the contents of the
 471 ; registers, except that this way you exchange the register names instead, so it
 472 ; doesn't cost any cycles.
 473
 474 %macro PERMUTE 2-* ; takes a list of pairs to swap
 475 %rep %0/2
 476     %xdefine tmp%2 m%2
 477     %xdefine ntmp%2 nm%2
 478     %rotate 2
 479 %endrep
 480 %rep %0/2
 481     %xdefine m%1 tmp%2
 482     %xdefine nm%1 ntmp%2
 483     %undef tmp%2
 484     %undef ntmp%2
 485     %rotate 2
 486 %endrep
 487 %endmacro
 488
 489 %macro SWAP 2-* ; swaps a single chain (sometimes more concise than pairs)
 490 %rep %0-1
 491 %ifdef m%1
 492     %xdefine tmp m%1
 493     %xdefine m%1 m%2
 494     %xdefine m%2 tmp
 495     CAT_XDEFINE n, m%1, %1
 496     CAT_XDEFINE n, m%2, %2
 497 %else
 498     ; If we were called as "SWAP m0,m1" rather than "SWAP 0,1" infer the original numbers here.
 499     ; Be careful using this mode in nested macros though, as in some cases there may be
 500     ; other copies of m# that have already been dereferenced and don't get updated correctly.
 501     %xdefine %%n1 n %+ %1
 502     %xdefine %%n2 n %+ %2
 503     %xdefine tmp m %+ %%n1
 504     CAT_XDEFINE m, %%n1, m %+ %%n2
 505     CAT_XDEFINE m, %%n2, tmp
 506     CAT_XDEFINE n, m %+ %%n1, %%n1
 507     CAT_XDEFINE n, m %+ %%n2, %%n2
 508 %endif
 509     %undef tmp
 510     %rotate 1
 511 %endrep
 512 %endmacro
 513
 514 %macro SAVE_MM_PERMUTATION 1
 515     %assign %%i 0
 516     %rep num_mmregs
 517     CAT_XDEFINE %1_m, %%i, m %+ %%i
 518     %assign %%i %%i+1
 519     %endrep
 520 %endmacro
 521
 522 %macro LOAD_MM_PERMUTATION 1
 523     %assign %%i 0
 524     %rep num_mmregs
 525     CAT_XDEFINE m, %%i, %1_m %+ %%i
 526     %assign %%i %%i+1
 527     %endrep
 528 %endmacro
 529
 530 %macro call 1
 531     call %1
 532     %ifdef %1_m0
 533         LOAD_MM_PERMUTATION %1
 534     %endif
 535 %endmacro
 536
 537 ; substitutions which are functionally identical but reduce code size
 538 %define movdqa movaps
 539 %define movdqu movups
 540