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jidctflt-3dn.asm (17391B)


      1 ;
      2 ; jidctflt.asm - floating-point IDCT (3DNow! & MMX)
      3 ;
      4 ; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
      5 ; Copyright (C) 2016, 2024, D. R. Commander.
      6 ;
      7 ; Based on the x86 SIMD extension for IJG JPEG library
      8 ; Copyright (C) 1999-2006, MIYASAKA Masaru.
      9 ; For conditions of distribution and use, see copyright notice in jsimdext.inc
     10 ;
     11 ; This file should be assembled with NASM (Netwide Assembler) or Yasm.
     12 ;
     13 ; This file contains a floating-point implementation of the inverse DCT
     14 ; (Discrete Cosine Transform). The following code is based directly on
     15 ; the IJG's original jidctflt.c; see the jidctflt.c for more details.
     16 
     17 %include "jsimdext.inc"
     18 %include "jdct.inc"
     19 
     20 ; --------------------------------------------------------------------------
     21    SECTION     SEG_CONST
     22 
     23    ALIGNZ      32
     24    GLOBAL_DATA(jconst_idct_float_3dnow)
     25 
     26 EXTN(jconst_idct_float_3dnow):
     27 
     28 PD_1_414        times 2 dd 1.414213562373095048801689
     29 PD_1_847        times 2 dd 1.847759065022573512256366
     30 PD_1_082        times 2 dd 1.082392200292393968799446
     31 PD_2_613        times 2 dd 2.613125929752753055713286
     32 PD_RNDINT_MAGIC times 2 dd 100663296.0  ; (float)(0x00C00000 << 3)
     33 PB_CENTERJSAMP  times 8 db CENTERJSAMPLE
     34 
     35    ALIGNZ      32
     36 
     37 ; --------------------------------------------------------------------------
     38    SECTION     SEG_TEXT
     39    BITS        32
     40 ;
     41 ; Perform dequantization and inverse DCT on one block of coefficients.
     42 ;
     43 ; GLOBAL(void)
     44 ; jsimd_idct_float_3dnow(void *dct_table, JCOEFPTR coef_block,
     45 ;                        JSAMPARRAY output_buf, JDIMENSION output_col)
     46 ;
     47 
     48 %define dct_table(b)   (b) + 8          ; void *dct_table
     49 %define coef_block(b)  (b) + 12         ; JCOEFPTR coef_block
     50 %define output_buf(b)  (b) + 16         ; JSAMPARRAY output_buf
     51 %define output_col(b)  (b) + 20         ; JDIMENSION output_col
     52 
     53 %define original_ebp   ebp + 0
     54 %define wk(i)          ebp - (WK_NUM - (i)) * SIZEOF_MMWORD
     55                                        ; mmword wk[WK_NUM]
     56 %define WK_NUM         2
     57 %define workspace      wk(0) - DCTSIZE2 * SIZEOF_FAST_FLOAT
     58                                        ; FAST_FLOAT workspace[DCTSIZE2]
     59 
     60    align       32
     61    GLOBAL_FUNCTION(jsimd_idct_float_3dnow)
     62 
     63 EXTN(jsimd_idct_float_3dnow):
     64    push        ebp
     65    mov         eax, esp                    ; eax = original ebp
     66    sub         esp, byte 4
     67    and         esp, byte (-SIZEOF_MMWORD)  ; align to 64 bits
     68    mov         [esp], eax
     69    mov         ebp, esp                    ; ebp = aligned ebp
     70    lea         esp, [workspace]
     71    push        ebx
     72 ;   push        ecx                     ; need not be preserved
     73 ;   push        edx                     ; need not be preserved
     74    push        esi
     75    push        edi
     76 
     77    GET_GOT     ebx                     ; get GOT address
     78 
     79    ; ---- Pass 1: process columns from input, store into work array.
     80 
     81 ;   mov         eax, [original_ebp]
     82    mov         edx, POINTER [dct_table(eax)]    ; quantptr
     83    mov         esi, JCOEFPTR [coef_block(eax)]  ; inptr
     84    lea         edi, [workspace]                 ; FAST_FLOAT *wsptr
     85    mov         ecx, DCTSIZE/2                   ; ctr
     86    ALIGNX      16, 7
     87 .columnloop:
     88 %ifndef NO_ZERO_COLUMN_TEST_FLOAT_3DNOW
     89    mov         eax, dword [DWBLOCK(1,0,esi,SIZEOF_JCOEF)]
     90    or          eax, dword [DWBLOCK(2,0,esi,SIZEOF_JCOEF)]
     91    jnz         short .columnDCT
     92 
     93    PUSHPIC     ebx                     ; save GOT address
     94    mov         ebx, dword [DWBLOCK(3,0,esi,SIZEOF_JCOEF)]
     95    mov         eax, dword [DWBLOCK(4,0,esi,SIZEOF_JCOEF)]
     96    or          ebx, dword [DWBLOCK(5,0,esi,SIZEOF_JCOEF)]
     97    or          eax, dword [DWBLOCK(6,0,esi,SIZEOF_JCOEF)]
     98    or          ebx, dword [DWBLOCK(7,0,esi,SIZEOF_JCOEF)]
     99    or          eax, ebx
    100    POPPIC      ebx                     ; restore GOT address
    101    jnz         short .columnDCT
    102 
    103    ; -- AC terms all zero
    104 
    105    movd        mm0, dword [DWBLOCK(0,0,esi,SIZEOF_JCOEF)]
    106 
    107    punpcklwd   mm0, mm0
    108    psrad       mm0, (DWORD_BIT-WORD_BIT)
    109    pi2fd       mm0, mm0
    110 
    111    pfmul       mm0, MMWORD [MMBLOCK(0,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    112 
    113    movq        mm1, mm0
    114    punpckldq   mm0, mm0
    115    punpckhdq   mm1, mm1
    116 
    117    movq        MMWORD [MMBLOCK(0,0,edi,SIZEOF_FAST_FLOAT)], mm0
    118    movq        MMWORD [MMBLOCK(0,1,edi,SIZEOF_FAST_FLOAT)], mm0
    119    movq        MMWORD [MMBLOCK(0,2,edi,SIZEOF_FAST_FLOAT)], mm0
    120    movq        MMWORD [MMBLOCK(0,3,edi,SIZEOF_FAST_FLOAT)], mm0
    121    movq        MMWORD [MMBLOCK(1,0,edi,SIZEOF_FAST_FLOAT)], mm1
    122    movq        MMWORD [MMBLOCK(1,1,edi,SIZEOF_FAST_FLOAT)], mm1
    123    movq        MMWORD [MMBLOCK(1,2,edi,SIZEOF_FAST_FLOAT)], mm1
    124    movq        MMWORD [MMBLOCK(1,3,edi,SIZEOF_FAST_FLOAT)], mm1
    125    jmp         near .nextcolumn
    126    ALIGNX      16, 7
    127 %endif
    128 .columnDCT:
    129 
    130    ; -- Even part
    131 
    132    movd        mm0, dword [DWBLOCK(0,0,esi,SIZEOF_JCOEF)]
    133    movd        mm1, dword [DWBLOCK(2,0,esi,SIZEOF_JCOEF)]
    134    movd        mm2, dword [DWBLOCK(4,0,esi,SIZEOF_JCOEF)]
    135    movd        mm3, dword [DWBLOCK(6,0,esi,SIZEOF_JCOEF)]
    136 
    137    punpcklwd   mm0, mm0
    138    punpcklwd   mm1, mm1
    139    psrad       mm0, (DWORD_BIT-WORD_BIT)
    140    psrad       mm1, (DWORD_BIT-WORD_BIT)
    141    pi2fd       mm0, mm0
    142    pi2fd       mm1, mm1
    143 
    144    pfmul       mm0, MMWORD [MMBLOCK(0,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    145    pfmul       mm1, MMWORD [MMBLOCK(2,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    146 
    147    punpcklwd   mm2, mm2
    148    punpcklwd   mm3, mm3
    149    psrad       mm2, (DWORD_BIT-WORD_BIT)
    150    psrad       mm3, (DWORD_BIT-WORD_BIT)
    151    pi2fd       mm2, mm2
    152    pi2fd       mm3, mm3
    153 
    154    pfmul       mm2, MMWORD [MMBLOCK(4,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    155    pfmul       mm3, MMWORD [MMBLOCK(6,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    156 
    157    movq        mm4, mm0
    158    movq        mm5, mm1
    159    pfsub       mm0, mm2                ; mm0=tmp11
    160    pfsub       mm1, mm3
    161    pfadd       mm4, mm2                ; mm4=tmp10
    162    pfadd       mm5, mm3                ; mm5=tmp13
    163 
    164    pfmul       mm1, [GOTOFF(ebx,PD_1_414)]
    165    pfsub       mm1, mm5                ; mm1=tmp12
    166 
    167    movq        mm6, mm4
    168    movq        mm7, mm0
    169    pfsub       mm4, mm5                ; mm4=tmp3
    170    pfsub       mm0, mm1                ; mm0=tmp2
    171    pfadd       mm6, mm5                ; mm6=tmp0
    172    pfadd       mm7, mm1                ; mm7=tmp1
    173 
    174    movq        MMWORD [wk(1)], mm4     ; tmp3
    175    movq        MMWORD [wk(0)], mm0     ; tmp2
    176 
    177    ; -- Odd part
    178 
    179    movd        mm2, dword [DWBLOCK(1,0,esi,SIZEOF_JCOEF)]
    180    movd        mm3, dword [DWBLOCK(3,0,esi,SIZEOF_JCOEF)]
    181    movd        mm5, dword [DWBLOCK(5,0,esi,SIZEOF_JCOEF)]
    182    movd        mm1, dword [DWBLOCK(7,0,esi,SIZEOF_JCOEF)]
    183 
    184    punpcklwd   mm2, mm2
    185    punpcklwd   mm3, mm3
    186    psrad       mm2, (DWORD_BIT-WORD_BIT)
    187    psrad       mm3, (DWORD_BIT-WORD_BIT)
    188    pi2fd       mm2, mm2
    189    pi2fd       mm3, mm3
    190 
    191    pfmul       mm2, MMWORD [MMBLOCK(1,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    192    pfmul       mm3, MMWORD [MMBLOCK(3,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    193 
    194    punpcklwd   mm5, mm5
    195    punpcklwd   mm1, mm1
    196    psrad       mm5, (DWORD_BIT-WORD_BIT)
    197    psrad       mm1, (DWORD_BIT-WORD_BIT)
    198    pi2fd       mm5, mm5
    199    pi2fd       mm1, mm1
    200 
    201    pfmul       mm5, MMWORD [MMBLOCK(5,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    202    pfmul       mm1, MMWORD [MMBLOCK(7,0,edx,SIZEOF_FLOAT_MULT_TYPE)]
    203 
    204    movq        mm4, mm2
    205    movq        mm0, mm5
    206    pfadd       mm2, mm1                ; mm2=z11
    207    pfadd       mm5, mm3                ; mm5=z13
    208    pfsub       mm4, mm1                ; mm4=z12
    209    pfsub       mm0, mm3                ; mm0=z10
    210 
    211    movq        mm1, mm2
    212    pfsub       mm2, mm5
    213    pfadd       mm1, mm5                ; mm1=tmp7
    214 
    215    pfmul       mm2, [GOTOFF(ebx,PD_1_414)]  ; mm2=tmp11
    216 
    217    movq        mm3, mm0
    218    pfadd       mm0, mm4
    219    pfmul       mm0, [GOTOFF(ebx,PD_1_847)]  ; mm0=z5
    220    pfmul       mm3, [GOTOFF(ebx,PD_2_613)]  ; mm3=(z10 * 2.613125930)
    221    pfmul       mm4, [GOTOFF(ebx,PD_1_082)]  ; mm4=(z12 * 1.082392200)
    222    pfsubr      mm3, mm0                     ; mm3=tmp12
    223    pfsub       mm4, mm0                     ; mm4=tmp10
    224 
    225    ; -- Final output stage
    226 
    227    pfsub       mm3, mm1                ; mm3=tmp6
    228    movq        mm5, mm6
    229    movq        mm0, mm7
    230    pfadd       mm6, mm1                ; mm6=data0=(00 01)
    231    pfadd       mm7, mm3                ; mm7=data1=(10 11)
    232    pfsub       mm5, mm1                ; mm5=data7=(70 71)
    233    pfsub       mm0, mm3                ; mm0=data6=(60 61)
    234    pfsub       mm2, mm3                ; mm2=tmp5
    235 
    236    movq        mm1, mm6                ; transpose coefficients
    237    punpckldq   mm6, mm7                ; mm6=(00 10)
    238    punpckhdq   mm1, mm7                ; mm1=(01 11)
    239    movq        mm3, mm0                ; transpose coefficients
    240    punpckldq   mm0, mm5                ; mm0=(60 70)
    241    punpckhdq   mm3, mm5                ; mm3=(61 71)
    242 
    243    movq        MMWORD [MMBLOCK(0,0,edi,SIZEOF_FAST_FLOAT)], mm6
    244    movq        MMWORD [MMBLOCK(1,0,edi,SIZEOF_FAST_FLOAT)], mm1
    245    movq        MMWORD [MMBLOCK(0,3,edi,SIZEOF_FAST_FLOAT)], mm0
    246    movq        MMWORD [MMBLOCK(1,3,edi,SIZEOF_FAST_FLOAT)], mm3
    247 
    248    movq        mm7, MMWORD [wk(0)]     ; mm7=tmp2
    249    movq        mm5, MMWORD [wk(1)]     ; mm5=tmp3
    250 
    251    pfadd       mm4, mm2                ; mm4=tmp4
    252    movq        mm6, mm7
    253    movq        mm1, mm5
    254    pfadd       mm7, mm2                ; mm7=data2=(20 21)
    255    pfadd       mm5, mm4                ; mm5=data4=(40 41)
    256    pfsub       mm6, mm2                ; mm6=data5=(50 51)
    257    pfsub       mm1, mm4                ; mm1=data3=(30 31)
    258 
    259    movq        mm0, mm7                ; transpose coefficients
    260    punpckldq   mm7, mm1                ; mm7=(20 30)
    261    punpckhdq   mm0, mm1                ; mm0=(21 31)
    262    movq        mm3, mm5                ; transpose coefficients
    263    punpckldq   mm5, mm6                ; mm5=(40 50)
    264    punpckhdq   mm3, mm6                ; mm3=(41 51)
    265 
    266    movq        MMWORD [MMBLOCK(0,1,edi,SIZEOF_FAST_FLOAT)], mm7
    267    movq        MMWORD [MMBLOCK(1,1,edi,SIZEOF_FAST_FLOAT)], mm0
    268    movq        MMWORD [MMBLOCK(0,2,edi,SIZEOF_FAST_FLOAT)], mm5
    269    movq        MMWORD [MMBLOCK(1,2,edi,SIZEOF_FAST_FLOAT)], mm3
    270 
    271 .nextcolumn:
    272    add         esi, byte 2*SIZEOF_JCOEF               ; coef_block
    273    add         edx, byte 2*SIZEOF_FLOAT_MULT_TYPE     ; quantptr
    274    add         edi, byte 2*DCTSIZE*SIZEOF_FAST_FLOAT  ; wsptr
    275    dec         ecx                                    ; ctr
    276    jnz         near .columnloop
    277 
    278    ; -- Prefetch the next coefficient block
    279 
    280    prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 0*32]
    281    prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 1*32]
    282    prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 2*32]
    283    prefetch [esi + (DCTSIZE2-8)*SIZEOF_JCOEF + 3*32]
    284 
    285    ; ---- Pass 2: process rows from work array, store into output array.
    286 
    287    mov         eax, [original_ebp]
    288    lea         esi, [workspace]                   ; FAST_FLOAT *wsptr
    289    mov         edi, JSAMPARRAY [output_buf(eax)]  ; (JSAMPROW *)
    290    mov         eax, JDIMENSION [output_col(eax)]
    291    mov         ecx, DCTSIZE/2                     ; ctr
    292    ALIGNX      16, 7
    293 .rowloop:
    294 
    295    ; -- Even part
    296 
    297    movq        mm0, MMWORD [MMBLOCK(0,0,esi,SIZEOF_FAST_FLOAT)]
    298    movq        mm1, MMWORD [MMBLOCK(2,0,esi,SIZEOF_FAST_FLOAT)]
    299    movq        mm2, MMWORD [MMBLOCK(4,0,esi,SIZEOF_FAST_FLOAT)]
    300    movq        mm3, MMWORD [MMBLOCK(6,0,esi,SIZEOF_FAST_FLOAT)]
    301 
    302    movq        mm4, mm0
    303    movq        mm5, mm1
    304    pfsub       mm0, mm2                ; mm0=tmp11
    305    pfsub       mm1, mm3
    306    pfadd       mm4, mm2                ; mm4=tmp10
    307    pfadd       mm5, mm3                ; mm5=tmp13
    308 
    309    pfmul       mm1, [GOTOFF(ebx,PD_1_414)]
    310    pfsub       mm1, mm5                ; mm1=tmp12
    311 
    312    movq        mm6, mm4
    313    movq        mm7, mm0
    314    pfsub       mm4, mm5                ; mm4=tmp3
    315    pfsub       mm0, mm1                ; mm0=tmp2
    316    pfadd       mm6, mm5                ; mm6=tmp0
    317    pfadd       mm7, mm1                ; mm7=tmp1
    318 
    319    movq        MMWORD [wk(1)], mm4     ; tmp3
    320    movq        MMWORD [wk(0)], mm0     ; tmp2
    321 
    322    ; -- Odd part
    323 
    324    movq        mm2, MMWORD [MMBLOCK(1,0,esi,SIZEOF_FAST_FLOAT)]
    325    movq        mm3, MMWORD [MMBLOCK(3,0,esi,SIZEOF_FAST_FLOAT)]
    326    movq        mm5, MMWORD [MMBLOCK(5,0,esi,SIZEOF_FAST_FLOAT)]
    327    movq        mm1, MMWORD [MMBLOCK(7,0,esi,SIZEOF_FAST_FLOAT)]
    328 
    329    movq        mm4, mm2
    330    movq        mm0, mm5
    331    pfadd       mm2, mm1                ; mm2=z11
    332    pfadd       mm5, mm3                ; mm5=z13
    333    pfsub       mm4, mm1                ; mm4=z12
    334    pfsub       mm0, mm3                ; mm0=z10
    335 
    336    movq        mm1, mm2
    337    pfsub       mm2, mm5
    338    pfadd       mm1, mm5                ; mm1=tmp7
    339 
    340    pfmul       mm2, [GOTOFF(ebx,PD_1_414)]  ; mm2=tmp11
    341 
    342    movq        mm3, mm0
    343    pfadd       mm0, mm4
    344    pfmul       mm0, [GOTOFF(ebx,PD_1_847)]  ; mm0=z5
    345    pfmul       mm3, [GOTOFF(ebx,PD_2_613)]  ; mm3=(z10 * 2.613125930)
    346    pfmul       mm4, [GOTOFF(ebx,PD_1_082)]  ; mm4=(z12 * 1.082392200)
    347    pfsubr      mm3, mm0                     ; mm3=tmp12
    348    pfsub       mm4, mm0                     ; mm4=tmp10
    349 
    350    ; -- Final output stage
    351 
    352    pfsub       mm3, mm1                ; mm3=tmp6
    353    movq        mm5, mm6
    354    movq        mm0, mm7
    355    pfadd       mm6, mm1                ; mm6=data0=(00 10)
    356    pfadd       mm7, mm3                ; mm7=data1=(01 11)
    357    pfsub       mm5, mm1                ; mm5=data7=(07 17)
    358    pfsub       mm0, mm3                ; mm0=data6=(06 16)
    359    pfsub       mm2, mm3                ; mm2=tmp5
    360 
    361    movq        mm1, [GOTOFF(ebx,PD_RNDINT_MAGIC)]  ; mm1=[PD_RNDINT_MAGIC]
    362    pcmpeqd     mm3, mm3
    363    psrld       mm3, WORD_BIT           ; mm3={0xFFFF 0x0000 0xFFFF 0x0000}
    364 
    365    pfadd       mm6, mm1                ; mm6=roundint(data0/8)=(00 ** 10 **)
    366    pfadd       mm7, mm1                ; mm7=roundint(data1/8)=(01 ** 11 **)
    367    pfadd       mm0, mm1                ; mm0=roundint(data6/8)=(06 ** 16 **)
    368    pfadd       mm5, mm1                ; mm5=roundint(data7/8)=(07 ** 17 **)
    369 
    370    pand        mm6, mm3                ; mm6=(00 -- 10 --)
    371    pslld       mm7, WORD_BIT           ; mm7=(-- 01 -- 11)
    372    pand        mm0, mm3                ; mm0=(06 -- 16 --)
    373    pslld       mm5, WORD_BIT           ; mm5=(-- 07 -- 17)
    374    por         mm6, mm7                ; mm6=(00 01 10 11)
    375    por         mm0, mm5                ; mm0=(06 07 16 17)
    376 
    377    movq        mm1, MMWORD [wk(0)]     ; mm1=tmp2
    378    movq        mm3, MMWORD [wk(1)]     ; mm3=tmp3
    379 
    380    pfadd       mm4, mm2                ; mm4=tmp4
    381    movq        mm7, mm1
    382    movq        mm5, mm3
    383    pfadd       mm1, mm2                ; mm1=data2=(02 12)
    384    pfadd       mm3, mm4                ; mm3=data4=(04 14)
    385    pfsub       mm7, mm2                ; mm7=data5=(05 15)
    386    pfsub       mm5, mm4                ; mm5=data3=(03 13)
    387 
    388    movq        mm2, [GOTOFF(ebx,PD_RNDINT_MAGIC)]  ; mm2=[PD_RNDINT_MAGIC]
    389    pcmpeqd     mm4, mm4
    390    psrld       mm4, WORD_BIT           ; mm4={0xFFFF 0x0000 0xFFFF 0x0000}
    391 
    392    pfadd       mm3, mm2                ; mm3=roundint(data4/8)=(04 ** 14 **)
    393    pfadd       mm7, mm2                ; mm7=roundint(data5/8)=(05 ** 15 **)
    394    pfadd       mm1, mm2                ; mm1=roundint(data2/8)=(02 ** 12 **)
    395    pfadd       mm5, mm2                ; mm5=roundint(data3/8)=(03 ** 13 **)
    396 
    397    pand        mm3, mm4                ; mm3=(04 -- 14 --)
    398    pslld       mm7, WORD_BIT           ; mm7=(-- 05 -- 15)
    399    pand        mm1, mm4                ; mm1=(02 -- 12 --)
    400    pslld       mm5, WORD_BIT           ; mm5=(-- 03 -- 13)
    401    por         mm3, mm7                ; mm3=(04 05 14 15)
    402    por         mm1, mm5                ; mm1=(02 03 12 13)
    403 
    404    movq        mm2, [GOTOFF(ebx,PB_CENTERJSAMP)]  ; mm2=[PB_CENTERJSAMP]
    405 
    406    packsswb    mm6, mm3                ; mm6=(00 01 10 11 04 05 14 15)
    407    packsswb    mm1, mm0                ; mm1=(02 03 12 13 06 07 16 17)
    408    paddb       mm6, mm2
    409    paddb       mm1, mm2
    410 
    411    movq        mm4, mm6                ; transpose coefficients(phase 2)
    412    punpcklwd   mm6, mm1                ; mm6=(00 01 02 03 10 11 12 13)
    413    punpckhwd   mm4, mm1                ; mm4=(04 05 06 07 14 15 16 17)
    414 
    415    movq        mm7, mm6                ; transpose coefficients(phase 3)
    416    punpckldq   mm6, mm4                ; mm6=(00 01 02 03 04 05 06 07)
    417    punpckhdq   mm7, mm4                ; mm7=(10 11 12 13 14 15 16 17)
    418 
    419    PUSHPIC     ebx                     ; save GOT address
    420 
    421    mov         edx, JSAMPROW [edi+0*SIZEOF_JSAMPROW]
    422    mov         ebx, JSAMPROW [edi+1*SIZEOF_JSAMPROW]
    423    movq        MMWORD [edx+eax*SIZEOF_JSAMPLE], mm6
    424    movq        MMWORD [ebx+eax*SIZEOF_JSAMPLE], mm7
    425 
    426    POPPIC      ebx                     ; restore GOT address
    427 
    428    add         esi, byte 2*SIZEOF_FAST_FLOAT  ; wsptr
    429    add         edi, byte 2*SIZEOF_JSAMPROW
    430    dec         ecx                            ; ctr
    431    jnz         near .rowloop
    432 
    433    femms                               ; empty MMX/3DNow! state
    434 
    435    pop         edi
    436    pop         esi
    437 ;   pop         edx                     ; need not be preserved
    438 ;   pop         ecx                     ; need not be preserved
    439    pop         ebx
    440    mov         esp, ebp                ; esp <- aligned ebp
    441    pop         esp                     ; esp <- original ebp
    442    pop         ebp
    443    ret
    444 
    445 ; For some reason, the OS X linker does not honor the request to align the
    446 ; segment unless we do this.
    447    align       32