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kc3-lang/libjpeg-turbo/simd/i386/jidctred-mmx.asm

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  • Author : DRC
    Date : 2025-09-19 14:21:49
    Hash : 5e27ca23
    Message : x86: Reformat NASM code to improve readability (and simplify the checkstyle script)

  • simd/i386/jidctred-mmx.asm
  • ;
    ; Reduced-size IDCT (32-bit MMX)
    ;
    ; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
    ; Copyright (C) 2016, 2024-2025, D. R. Commander.
    ;
    ; Based on the x86 SIMD extension for IJG JPEG library
    ; Copyright (C) 1999-2006, MIYASAKA Masaru.
    ; For conditions of distribution and use, see copyright notice in jsimdext.inc
    ;
    ; This file should be assembled with NASM (Netwide Assembler) or Yasm.
    ;
    ; This file contains inverse DCT routines that produce reduced-size output:
    ; either 4x4 or 2x2 pixels from an 8x8 DCT block.  The following code is based
    ; directly on the IJG's original jidctred.c; see jidctred.c for more details.
    
    %include "jsimdext.inc"
    %include "jdct.inc"
    
    ; --------------------------------------------------------------------------
    
    %define CONST_BITS    13
    %define PASS1_BITS    2
    
    %define DESCALE_P1_4  (CONST_BITS - PASS1_BITS + 1)
    %define DESCALE_P2_4  (CONST_BITS + PASS1_BITS + 3 + 1)
    %define DESCALE_P1_2  (CONST_BITS - PASS1_BITS + 2)
    %define DESCALE_P2_2  (CONST_BITS + PASS1_BITS + 3 + 2)
    
    %if CONST_BITS == 13
    F_0_211 equ  1730  ; FIX(0.211164243)
    F_0_509 equ  4176  ; FIX(0.509795579)
    F_0_601 equ  4926  ; FIX(0.601344887)
    F_0_720 equ  5906  ; FIX(0.720959822)
    F_0_765 equ  6270  ; FIX(0.765366865)
    F_0_850 equ  6967  ; FIX(0.850430095)
    F_0_899 equ  7373  ; FIX(0.899976223)
    F_1_061 equ  8697  ; FIX(1.061594337)
    F_1_272 equ 10426  ; FIX(1.272758580)
    F_1_451 equ 11893  ; FIX(1.451774981)
    F_1_847 equ 15137  ; FIX(1.847759065)
    F_2_172 equ 17799  ; FIX(2.172734803)
    F_2_562 equ 20995  ; FIX(2.562915447)
    F_3_624 equ 29692  ; FIX(3.624509785)
    %else
    ; NASM cannot do compile-time arithmetic on floating-point constants.
    %define DESCALE(x, n)  (((x) + (1 << ((n) - 1))) >> (n))
    F_0_211 equ DESCALE( 226735879, 30 - CONST_BITS)  ; FIX(0.211164243)
    F_0_509 equ DESCALE( 547388834, 30 - CONST_BITS)  ; FIX(0.509795579)
    F_0_601 equ DESCALE( 645689155, 30 - CONST_BITS)  ; FIX(0.601344887)
    F_0_720 equ DESCALE( 774124714, 30 - CONST_BITS)  ; FIX(0.720959822)
    F_0_765 equ DESCALE( 821806413, 30 - CONST_BITS)  ; FIX(0.765366865)
    F_0_850 equ DESCALE( 913142361, 30 - CONST_BITS)  ; FIX(0.850430095)
    F_0_899 equ DESCALE( 966342111, 30 - CONST_BITS)  ; FIX(0.899976223)
    F_1_061 equ DESCALE(1139878239, 30 - CONST_BITS)  ; FIX(1.061594337)
    F_1_272 equ DESCALE(1366614119, 30 - CONST_BITS)  ; FIX(1.272758580)
    F_1_451 equ DESCALE(1558831516, 30 - CONST_BITS)  ; FIX(1.451774981)
    F_1_847 equ DESCALE(1984016188, 30 - CONST_BITS)  ; FIX(1.847759065)
    F_2_172 equ DESCALE(2332956230, 30 - CONST_BITS)  ; FIX(2.172734803)
    F_2_562 equ DESCALE(2751909506, 30 - CONST_BITS)  ; FIX(2.562915447)
    F_3_624 equ DESCALE(3891787747, 30 - CONST_BITS)  ; FIX(3.624509785)
    %endif
    
    ; --------------------------------------------------------------------------
        SECTION     SEG_CONST
    
        ALIGNZ      32
        GLOBAL_DATA(jconst_idct_red_mmx)
    
    EXTN(jconst_idct_red_mmx):
    
    PW_F184_MF076   times 2 dw  F_1_847, -F_0_765
    PW_F256_F089    times 2 dw  F_2_562,  F_0_899
    PW_F106_MF217   times 2 dw  F_1_061, -F_2_172
    PW_MF060_MF050  times 2 dw -F_0_601, -F_0_509
    PW_F145_MF021   times 2 dw  F_1_451, -F_0_211
    PW_F362_MF127   times 2 dw  F_3_624, -F_1_272
    PW_F085_MF072   times 2 dw  F_0_850, -F_0_720
    PD_DESCALE_P1_4 times 2 dd  1 << (DESCALE_P1_4 - 1)
    PD_DESCALE_P2_4 times 2 dd  1 << (DESCALE_P2_4 - 1)
    PD_DESCALE_P1_2 times 2 dd  1 << (DESCALE_P1_2 - 1)
    PD_DESCALE_P2_2 times 2 dd  1 << (DESCALE_P2_2 - 1)
    PB_CENTERJSAMP  times 8 db  CENTERJSAMPLE
    
        ALIGNZ      32
    
    ; --------------------------------------------------------------------------
        SECTION     SEG_TEXT
        BITS        32
    
    ; Perform dequantization and inverse DCT on one block of coefficients,
    ; producing a reduced-size 4x4 output block.
    ;
    ; GLOBAL(void)
    ; jsimd_idct_4x4_mmx(void *dct_table, JCOEFPTR coef_block,
    ;                    JSAMPARRAY output_buf, JDIMENSION output_col)
    
    %define dct_table(b)   (b) + 8          ; void *dct_table
    %define coef_block(b)  (b) + 12         ; JCOEFPTR coef_block
    %define output_buf(b)  (b) + 16         ; JSAMPARRAY output_buf
    %define output_col(b)  (b) + 20         ; JDIMENSION output_col
    
    %define original_ebp  ebp + 0
    %define wk(i)         ebp - (WK_NUM - (i)) * SIZEOF_MMWORD
                          ; mmword wk[WK_NUM]
    %define WK_NUM        2
    %define workspace     wk(0) - DCTSIZE2 * SIZEOF_JCOEF
                          ; JCOEF workspace[DCTSIZE2]
    
        align       32
        GLOBAL_FUNCTION(jsimd_idct_4x4_mmx)
    
    EXTN(jsimd_idct_4x4_mmx):
        push        ebp
        mov         eax, esp                ; eax = original ebp
        sub         esp, byte 4
        and         esp, byte (-SIZEOF_MMWORD)  ; align to 64 bits
        mov         [esp], eax
        mov         ebp, esp                ; ebp = aligned ebp
        lea         esp, [workspace]
        PUSHPIC     ebx
    ;   push        ecx                     ; need not be preserved
    ;   push        edx                     ; need not be preserved
        push        esi
        push        edi
    
        GET_GOT     ebx                     ; get GOT address
    
        ; ---- Pass 1: process columns from input, store into work array.
    
    ;   mov         eax, [original_ebp]
        mov         edx, POINTER [dct_table(eax)]    ; quantptr
        mov         esi, JCOEFPTR [coef_block(eax)]  ; inptr
        lea         edi, [workspace]                 ; JCOEF *wsptr
        mov         ecx, DCTSIZE / 4                 ; ctr
        ALIGNX      16, 7
    .columnloop:
    %ifndef NO_ZERO_COLUMN_TEST_4X4_MMX
        mov         eax, dword [DWBLOCK(1, 0, esi, SIZEOF_JCOEF)]
        or          eax, dword [DWBLOCK(2, 0, esi, SIZEOF_JCOEF)]
        jnz         short .columnDCT
    
        movq        mm0, MMWORD [MMBLOCK(1, 0, esi, SIZEOF_JCOEF)]
        movq        mm1, MMWORD [MMBLOCK(2, 0, esi, SIZEOF_JCOEF)]
        por         mm0, MMWORD [MMBLOCK(3, 0, esi, SIZEOF_JCOEF)]
        por         mm1, MMWORD [MMBLOCK(5, 0, esi, SIZEOF_JCOEF)]
        por         mm0, MMWORD [MMBLOCK(6, 0, esi, SIZEOF_JCOEF)]
        por         mm1, MMWORD [MMBLOCK(7, 0, esi, SIZEOF_JCOEF)]
        por         mm0, mm1
        packsswb    mm0, mm0
        movd        eax, mm0
        test        eax, eax
        jnz         short .columnDCT
    
        ; -- AC terms all zero
    
        movq        mm0, MMWORD [MMBLOCK(0, 0, esi, SIZEOF_JCOEF)]
        pmullw      mm0, MMWORD [MMBLOCK(0, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
    
        psllw       mm0, PASS1_BITS
    
        movq        mm2, mm0                ; mm0 = in0 = (00 01 02 03)
        punpcklwd   mm0, mm0                ; mm0 = (00 00 01 01)
        punpckhwd   mm2, mm2                ; mm2 = (02 02 03 03)
    
        movq        mm1, mm0
        punpckldq   mm0, mm0                ; mm0 = (00 00 00 00)
        punpckhdq   mm1, mm1                ; mm1 = (01 01 01 01)
        movq        mm3, mm2
        punpckldq   mm2, mm2                ; mm2 = (02 02 02 02)
        punpckhdq   mm3, mm3                ; mm3 = (03 03 03 03)
    
        movq        MMWORD [MMBLOCK(0, 0, edi, SIZEOF_JCOEF)], mm0
        movq        MMWORD [MMBLOCK(1, 0, edi, SIZEOF_JCOEF)], mm1
        movq        MMWORD [MMBLOCK(2, 0, edi, SIZEOF_JCOEF)], mm2
        movq        MMWORD [MMBLOCK(3, 0, edi, SIZEOF_JCOEF)], mm3
        jmp         near .nextcolumn
        ALIGNX      16, 7
    %endif
    .columnDCT:
    
        ; -- Odd part
    
        movq        mm0, MMWORD [MMBLOCK(1, 0, esi, SIZEOF_JCOEF)]
        movq        mm1, MMWORD [MMBLOCK(3, 0, esi, SIZEOF_JCOEF)]
        pmullw      mm0, MMWORD [MMBLOCK(1, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm1, MMWORD [MMBLOCK(3, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        movq        mm2, MMWORD [MMBLOCK(5, 0, esi, SIZEOF_JCOEF)]
        movq        mm3, MMWORD [MMBLOCK(7, 0, esi, SIZEOF_JCOEF)]
        pmullw      mm2, MMWORD [MMBLOCK(5, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm3, MMWORD [MMBLOCK(7, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
    
        movq        mm4, mm0
        movq        mm5, mm0
        punpcklwd   mm4, mm1
        punpckhwd   mm5, mm1
        movq        mm0, mm4
        movq        mm1, mm5
        pmaddwd     mm4, [GOTOFF(ebx, PW_F256_F089)]   ; mm4 = (tmp2L)
        pmaddwd     mm5, [GOTOFF(ebx, PW_F256_F089)]   ; mm5 = (tmp2H)
        pmaddwd     mm0, [GOTOFF(ebx, PW_F106_MF217)]  ; mm0 = (tmp0L)
        pmaddwd     mm1, [GOTOFF(ebx, PW_F106_MF217)]  ; mm1 = (tmp0H)
    
        movq        mm6, mm2
        movq        mm7, mm2
        punpcklwd   mm6, mm3
        punpckhwd   mm7, mm3
        movq        mm2, mm6
        movq        mm3, mm7
        pmaddwd     mm6, [GOTOFF(ebx, PW_MF060_MF050)]  ; mm6 = (tmp2L)
        pmaddwd     mm7, [GOTOFF(ebx, PW_MF060_MF050)]  ; mm7 = (tmp2H)
        pmaddwd     mm2, [GOTOFF(ebx, PW_F145_MF021)]   ; mm2 = (tmp0L)
        pmaddwd     mm3, [GOTOFF(ebx, PW_F145_MF021)]   ; mm3 = (tmp0H)
    
        paddd       mm6, mm4                ; mm6 = tmp2L
        paddd       mm7, mm5                ; mm7 = tmp2H
        paddd       mm2, mm0                ; mm2 = tmp0L
        paddd       mm3, mm1                ; mm3 = tmp0H
    
        movq        MMWORD [wk(0)], mm2     ; wk(0) = tmp0L
        movq        MMWORD [wk(1)], mm3     ; wk(1) = tmp0H
    
        ; -- Even part
    
        movq        mm4, MMWORD [MMBLOCK(0, 0, esi, SIZEOF_JCOEF)]
        movq        mm5, MMWORD [MMBLOCK(2, 0, esi, SIZEOF_JCOEF)]
        movq        mm0, MMWORD [MMBLOCK(6, 0, esi, SIZEOF_JCOEF)]
        pmullw      mm4, MMWORD [MMBLOCK(0, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm5, MMWORD [MMBLOCK(2, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm0, MMWORD [MMBLOCK(6, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
    
        pxor        mm1, mm1
        pxor        mm2, mm2
        punpcklwd   mm1, mm4                ; mm1 = tmp0L
        punpckhwd   mm2, mm4                ; mm2 = tmp0H
        psrad       mm1, (16 - CONST_BITS - 1)
                    ; psrad mm1, 16 & pslld mm1, CONST_BITS + 1
        psrad       mm2, (16 - CONST_BITS - 1)
                    ; psrad mm2, 16 & pslld mm2, CONST_BITS + 1
    
        movq        mm3, mm5                ; mm5 = in2 = z2
        punpcklwd   mm5, mm0                ; mm0 = in6 = z3
        punpckhwd   mm3, mm0
        pmaddwd     mm5, [GOTOFF(ebx, PW_F184_MF076)]  ; mm5 = tmp2L
        pmaddwd     mm3, [GOTOFF(ebx, PW_F184_MF076)]  ; mm3 = tmp2H
    
        movq        mm4, mm1
        movq        mm0, mm2
        paddd       mm1, mm5                ; mm1 = tmp10L
        paddd       mm2, mm3                ; mm2 = tmp10H
        psubd       mm4, mm5                ; mm4 = tmp12L
        psubd       mm0, mm3                ; mm0 = tmp12H
    
        ; -- Final output stage
    
        movq        mm5, mm1
        movq        mm3, mm2
        paddd       mm1, mm6                ; mm1 = data0L
        paddd       mm2, mm7                ; mm2 = data0H
        psubd       mm5, mm6                ; mm5 = data3L
        psubd       mm3, mm7                ; mm3 = data3H
    
        movq        mm6, [GOTOFF(ebx, PD_DESCALE_P1_4)]  ; mm6 = [PD_DESCALE_P1_4]
    
        paddd       mm1, mm6
        paddd       mm2, mm6
        psrad       mm1, DESCALE_P1_4
        psrad       mm2, DESCALE_P1_4
        paddd       mm5, mm6
        paddd       mm3, mm6
        psrad       mm5, DESCALE_P1_4
        psrad       mm3, DESCALE_P1_4
    
        packssdw    mm1, mm2                ; mm1 = data0 = (00 01 02 03)
        packssdw    mm5, mm3                ; mm5 = data3 = (30 31 32 33)
    
        movq        mm7, MMWORD [wk(0)]     ; mm7 = tmp0L
        movq        mm6, MMWORD [wk(1)]     ; mm6 = tmp0H
    
        movq        mm2, mm4
        movq        mm3, mm0
        paddd       mm4, mm7                ; mm4 = data1L
        paddd       mm0, mm6                ; mm0 = data1H
        psubd       mm2, mm7                ; mm2 = data2L
        psubd       mm3, mm6                ; mm3 = data2H
    
        movq        mm7, [GOTOFF(ebx, PD_DESCALE_P1_4)]  ; mm7 = [PD_DESCALE_P1_4]
    
        paddd       mm4, mm7
        paddd       mm0, mm7
        psrad       mm4, DESCALE_P1_4
        psrad       mm0, DESCALE_P1_4
        paddd       mm2, mm7
        paddd       mm3, mm7
        psrad       mm2, DESCALE_P1_4
        psrad       mm3, DESCALE_P1_4
    
        packssdw    mm4, mm0                ; mm4 = data1 = (10 11 12 13)
        packssdw    mm2, mm3                ; mm2 = data2 = (20 21 22 23)
    
        movq        mm6, mm1                ; transpose coefficients(phase 1)
        punpcklwd   mm1, mm4                ; mm1 = (00 10 01 11)
        punpckhwd   mm6, mm4                ; mm6 = (02 12 03 13)
        movq        mm7, mm2                ; transpose coefficients(phase 1)
        punpcklwd   mm2, mm5                ; mm2 = (20 30 21 31)
        punpckhwd   mm7, mm5                ; mm7 = (22 32 23 33)
    
        movq        mm0, mm1                ; transpose coefficients(phase 2)
        punpckldq   mm1, mm2                ; mm1 = (00 10 20 30)
        punpckhdq   mm0, mm2                ; mm0 = (01 11 21 31)
        movq        mm3, mm6                ; transpose coefficients(phase 2)
        punpckldq   mm6, mm7                ; mm6 = (02 12 22 32)
        punpckhdq   mm3, mm7                ; mm3 = (03 13 23 33)
    
        movq        MMWORD [MMBLOCK(0, 0, edi, SIZEOF_JCOEF)], mm1
        movq        MMWORD [MMBLOCK(1, 0, edi, SIZEOF_JCOEF)], mm0
        movq        MMWORD [MMBLOCK(2, 0, edi, SIZEOF_JCOEF)], mm6
        movq        MMWORD [MMBLOCK(3, 0, edi, SIZEOF_JCOEF)], mm3
    
    .nextcolumn:
        add         esi, byte 4 * SIZEOF_JCOEF            ; coef_block
        add         edx, byte 4 * SIZEOF_ISLOW_MULT_TYPE  ; quantptr
        add         edi, byte 4 * DCTSIZE * SIZEOF_JCOEF  ; wsptr
        dec         ecx                                   ; ctr
        jnz         near .columnloop
    
        ; ---- Pass 2: process rows from work array, store into output array.
    
        mov         eax, [original_ebp]
        lea         esi, [workspace]                   ; JCOEF *wsptr
        mov         edi, JSAMPARRAY [output_buf(eax)]  ; (JSAMPROW *)
        mov         eax, JDIMENSION [output_col(eax)]
    
        ; -- Odd part
    
        movq        mm0, MMWORD [MMBLOCK(1, 0, esi, SIZEOF_JCOEF)]
        movq        mm1, MMWORD [MMBLOCK(3, 0, esi, SIZEOF_JCOEF)]
        movq        mm2, MMWORD [MMBLOCK(5, 0, esi, SIZEOF_JCOEF)]
        movq        mm3, MMWORD [MMBLOCK(7, 0, esi, SIZEOF_JCOEF)]
    
        movq        mm4, mm0
        movq        mm5, mm0
        punpcklwd   mm4, mm1
        punpckhwd   mm5, mm1
        movq        mm0, mm4
        movq        mm1, mm5
        pmaddwd     mm4, [GOTOFF(ebx, PW_F256_F089)]   ; mm4 = (tmp2L)
        pmaddwd     mm5, [GOTOFF(ebx, PW_F256_F089)]   ; mm5 = (tmp2H)
        pmaddwd     mm0, [GOTOFF(ebx, PW_F106_MF217)]  ; mm0 = (tmp0L)
        pmaddwd     mm1, [GOTOFF(ebx, PW_F106_MF217)]  ; mm1 = (tmp0H)
    
        movq        mm6, mm2
        movq        mm7, mm2
        punpcklwd   mm6, mm3
        punpckhwd   mm7, mm3
        movq        mm2, mm6
        movq        mm3, mm7
        pmaddwd     mm6, [GOTOFF(ebx, PW_MF060_MF050)]  ; mm6 = (tmp2L)
        pmaddwd     mm7, [GOTOFF(ebx, PW_MF060_MF050)]  ; mm7 = (tmp2H)
        pmaddwd     mm2, [GOTOFF(ebx, PW_F145_MF021)]   ; mm2 = (tmp0L)
        pmaddwd     mm3, [GOTOFF(ebx, PW_F145_MF021)]   ; mm3 = (tmp0H)
    
        paddd       mm6, mm4                ; mm6 = tmp2L
        paddd       mm7, mm5                ; mm7 = tmp2H
        paddd       mm2, mm0                ; mm2 = tmp0L
        paddd       mm3, mm1                ; mm3 = tmp0H
    
        movq        MMWORD [wk(0)], mm2     ; wk(0) = tmp0L
        movq        MMWORD [wk(1)], mm3     ; wk(1) = tmp0H
    
        ; -- Even part
    
        movq        mm4, MMWORD [MMBLOCK(0, 0, esi, SIZEOF_JCOEF)]
        movq        mm5, MMWORD [MMBLOCK(2, 0, esi, SIZEOF_JCOEF)]
        movq        mm0, MMWORD [MMBLOCK(6, 0, esi, SIZEOF_JCOEF)]
    
        pxor        mm1, mm1
        pxor        mm2, mm2
        punpcklwd   mm1, mm4                ; mm1 = tmp0L
        punpckhwd   mm2, mm4                ; mm2 = tmp0H
        psrad       mm1, (16 - CONST_BITS - 1)
                    ; psrad mm1, 16 & pslld mm1, CONST_BITS + 1
        psrad       mm2, (16 - CONST_BITS - 1)
                    ; psrad mm2, 16 & pslld mm2, CONST_BITS + 1
    
        movq        mm3, mm5                ; mm5 = in2 = z2
        punpcklwd   mm5, mm0                ; mm0 = in6 = z3
        punpckhwd   mm3, mm0
        pmaddwd     mm5, [GOTOFF(ebx, PW_F184_MF076)]  ; mm5 = tmp2L
        pmaddwd     mm3, [GOTOFF(ebx, PW_F184_MF076)]  ; mm3 = tmp2H
    
        movq        mm4, mm1
        movq        mm0, mm2
        paddd       mm1, mm5                ; mm1 = tmp10L
        paddd       mm2, mm3                ; mm2 = tmp10H
        psubd       mm4, mm5                ; mm4 = tmp12L
        psubd       mm0, mm3                ; mm0 = tmp12H
    
        ; -- Final output stage
    
        movq        mm5, mm1
        movq        mm3, mm2
        paddd       mm1, mm6                ; mm1 = data0L
        paddd       mm2, mm7                ; mm2 = data0H
        psubd       mm5, mm6                ; mm5 = data3L
        psubd       mm3, mm7                ; mm3 = data3H
    
        movq        mm6, [GOTOFF(ebx, PD_DESCALE_P2_4)]  ; mm6 = [PD_DESCALE_P2_4]
    
        paddd       mm1, mm6
        paddd       mm2, mm6
        psrad       mm1, DESCALE_P2_4
        psrad       mm2, DESCALE_P2_4
        paddd       mm5, mm6
        paddd       mm3, mm6
        psrad       mm5, DESCALE_P2_4
        psrad       mm3, DESCALE_P2_4
    
        packssdw    mm1, mm2                ; mm1 = data0 = (00 10 20 30)
        packssdw    mm5, mm3                ; mm5 = data3 = (03 13 23 33)
    
        movq        mm7, MMWORD [wk(0)]     ; mm7 = tmp0L
        movq        mm6, MMWORD [wk(1)]     ; mm6 = tmp0H
    
        movq        mm2, mm4
        movq        mm3, mm0
        paddd       mm4, mm7                ; mm4 = data1L
        paddd       mm0, mm6                ; mm0 = data1H
        psubd       mm2, mm7                ; mm2 = data2L
        psubd       mm3, mm6                ; mm3 = data2H
    
        movq        mm7, [GOTOFF(ebx, PD_DESCALE_P2_4)]  ; mm7 = [PD_DESCALE_P2_4]
    
        paddd       mm4, mm7
        paddd       mm0, mm7
        psrad       mm4, DESCALE_P2_4
        psrad       mm0, DESCALE_P2_4
        paddd       mm2, mm7
        paddd       mm3, mm7
        psrad       mm2, DESCALE_P2_4
        psrad       mm3, DESCALE_P2_4
    
        packssdw    mm4, mm0                ; mm4 = data1 = (01 11 21 31)
        packssdw    mm2, mm3                ; mm2 = data2 = (02 12 22 32)
    
        movq        mm6, [GOTOFF(ebx, PB_CENTERJSAMP)]  ; mm6 = [PB_CENTERJSAMP]
    
        packsswb    mm1, mm2                ; mm1 = (00 10 20 30 02 12 22 32)
        packsswb    mm4, mm5                ; mm4 = (01 11 21 31 03 13 23 33)
        paddb       mm1, mm6
        paddb       mm4, mm6
    
        movq        mm7, mm1                ; transpose coefficients(phase 1)
        punpcklbw   mm1, mm4                ; mm1 = (00 01 10 11 20 21 30 31)
        punpckhbw   mm7, mm4                ; mm7 = (02 03 12 13 22 23 32 33)
    
        movq        mm0, mm1                ; transpose coefficients(phase 2)
        punpcklwd   mm1, mm7                ; mm1 = (00 01 02 03 10 11 12 13)
        punpckhwd   mm0, mm7                ; mm0 = (20 21 22 23 30 31 32 33)
    
        mov         edx, JSAMPROW [edi + 0 * SIZEOF_JSAMPROW]
        mov         esi, JSAMPROW [edi + 2 * SIZEOF_JSAMPROW]
        movd        dword [edx + eax * SIZEOF_JSAMPLE], mm1
        movd        dword [esi + eax * SIZEOF_JSAMPLE], mm0
    
        psrlq       mm1, 4 * BYTE_BIT
        psrlq       mm0, 4 * BYTE_BIT
    
        mov         edx, JSAMPROW [edi + 1 * SIZEOF_JSAMPROW]
        mov         esi, JSAMPROW [edi + 3 * SIZEOF_JSAMPROW]
        movd        dword [edx + eax * SIZEOF_JSAMPLE], mm1
        movd        dword [esi + eax * SIZEOF_JSAMPLE], mm0
    
        emms                                ; empty MMX state
    
        pop         edi
        pop         esi
    ;   pop         edx                     ; need not be preserved
    ;   pop         ecx                     ; need not be preserved
        POPPIC      ebx
        mov         esp, ebp                ; esp <- aligned ebp
        pop         esp                     ; esp <- original ebp
        pop         ebp
        ret
    
    ; --------------------------------------------------------------------------
    ;
    ; Perform dequantization and inverse DCT on one block of coefficients,
    ; producing a reduced-size 2x2 output block.
    ;
    ; GLOBAL(void)
    ; jsimd_idct_2x2_mmx(void *dct_table, JCOEFPTR coef_block,
    ;                    JSAMPARRAY output_buf, JDIMENSION output_col)
    
    %define dct_table(b)   (b) + 8          ; void *dct_table
    %define coef_block(b)  (b) + 12         ; JCOEFPTR coef_block
    %define output_buf(b)  (b) + 16         ; JSAMPARRAY output_buf
    %define output_col(b)  (b) + 20         ; JDIMENSION output_col
    
        align       32
        GLOBAL_FUNCTION(jsimd_idct_2x2_mmx)
    
    EXTN(jsimd_idct_2x2_mmx):
        push        ebp
        mov         ebp, esp
        push        ebx
    ;   push        ecx                     ; need not be preserved
    ;   push        edx                     ; need not be preserved
        push        esi
        push        edi
    
        GET_GOT     ebx                     ; get GOT address
    
        ; ---- Pass 1: process columns from input.
    
        mov         edx, POINTER [dct_table(ebp)]    ; quantptr
        mov         esi, JCOEFPTR [coef_block(ebp)]  ; inptr
    
        ; | input:                  | result:        |
        ; | 00 01 ** 03 ** 05 ** 07 |                |
        ; | 10 11 ** 13 ** 15 ** 17 |                |
        ; | ** ** ** ** ** ** ** ** |                |
        ; | 30 31 ** 33 ** 35 ** 37 | A0 A1 A3 A5 A7 |
        ; | ** ** ** ** ** ** ** ** | B0 B1 B3 B5 B7 |
        ; | 50 51 ** 53 ** 55 ** 57 |                |
        ; | ** ** ** ** ** ** ** ** |                |
        ; | 70 71 ** 73 ** 75 ** 77 |                |
    
        ; -- Odd part
    
        movq        mm0, MMWORD [MMBLOCK(1, 0, esi, SIZEOF_JCOEF)]
        movq        mm1, MMWORD [MMBLOCK(3, 0, esi, SIZEOF_JCOEF)]
        pmullw      mm0, MMWORD [MMBLOCK(1, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm1, MMWORD [MMBLOCK(3, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        movq        mm2, MMWORD [MMBLOCK(5, 0, esi, SIZEOF_JCOEF)]
        movq        mm3, MMWORD [MMBLOCK(7, 0, esi, SIZEOF_JCOEF)]
        pmullw      mm2, MMWORD [MMBLOCK(5, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm3, MMWORD [MMBLOCK(7, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
    
        ; mm0 = (10 11 ** 13)
        ; mm1 = (30 31 ** 33)
        ; mm2 = (50 51 ** 53)
        ; mm3 = (70 71 ** 73)
    
        pcmpeqd     mm7, mm7
        pslld       mm7, WORD_BIT           ; mm7 = { 0x0000 0xFFFF 0x0000 0xFFFF }
    
        movq        mm4, mm0                ; mm4 = (10 11 ** 13)
        movq        mm5, mm2                ; mm5 = (50 51 ** 53)
        punpcklwd   mm4, mm1                ; mm4 = (10 30 11 31)
        punpcklwd   mm5, mm3                ; mm5 = (50 70 51 71)
        pmaddwd     mm4, [GOTOFF(ebx, PW_F362_MF127)]
        pmaddwd     mm5, [GOTOFF(ebx, PW_F085_MF072)]
    
        psrld       mm0, WORD_BIT           ; mm0 = (11 -- 13 --)
        pand        mm1, mm7                ; mm1 = (-- 31 -- 33)
        psrld       mm2, WORD_BIT           ; mm2 = (51 -- 53 --)
        pand        mm3, mm7                ; mm3 = (-- 71 -- 73)
        por         mm0, mm1                ; mm0 = (11 31 13 33)
        por         mm2, mm3                ; mm2 = (51 71 53 73)
        pmaddwd     mm0, [GOTOFF(ebx, PW_F362_MF127)]
        pmaddwd     mm2, [GOTOFF(ebx, PW_F085_MF072)]
    
        paddd       mm4, mm5                ; mm4 = tmp0[col0 col1]
    
        movq        mm6, MMWORD [MMBLOCK(1, 1, esi, SIZEOF_JCOEF)]
        movq        mm1, MMWORD [MMBLOCK(3, 1, esi, SIZEOF_JCOEF)]
        pmullw      mm6, MMWORD [MMBLOCK(1, 1, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm1, MMWORD [MMBLOCK(3, 1, edx, SIZEOF_ISLOW_MULT_TYPE)]
        movq        mm3, MMWORD [MMBLOCK(5, 1, esi, SIZEOF_JCOEF)]
        movq        mm5, MMWORD [MMBLOCK(7, 1, esi, SIZEOF_JCOEF)]
        pmullw      mm3, MMWORD [MMBLOCK(5, 1, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm5, MMWORD [MMBLOCK(7, 1, edx, SIZEOF_ISLOW_MULT_TYPE)]
    
        ; mm6 = (** 15 ** 17)
        ; mm1 = (** 35 ** 37)
        ; mm3 = (** 55 ** 57)
        ; mm5 = (** 75 ** 77)
    
        psrld       mm6, WORD_BIT           ; mm6 = (15 -- 17 --)
        pand        mm1, mm7                ; mm1 = (-- 35 -- 37)
        psrld       mm3, WORD_BIT           ; mm3 = (55 -- 57 --)
        pand        mm5, mm7                ; mm5 = (-- 75 -- 77)
        por         mm6, mm1                ; mm6 = (15 35 17 37)
        por         mm3, mm5                ; mm3 = (55 75 57 77)
        pmaddwd     mm6, [GOTOFF(ebx, PW_F362_MF127)]
        pmaddwd     mm3, [GOTOFF(ebx, PW_F085_MF072)]
    
        paddd       mm0, mm2                ; mm0 = tmp0[col1 col3]
        paddd       mm6, mm3                ; mm6 = tmp0[col5 col7]
    
        ; -- Even part
    
        movq        mm1, MMWORD [MMBLOCK(0, 0, esi, SIZEOF_JCOEF)]
        movq        mm5, MMWORD [MMBLOCK(0, 1, esi, SIZEOF_JCOEF)]
        pmullw      mm1, MMWORD [MMBLOCK(0, 0, edx, SIZEOF_ISLOW_MULT_TYPE)]
        pmullw      mm5, MMWORD [MMBLOCK(0, 1, edx, SIZEOF_ISLOW_MULT_TYPE)]
    
        ; mm1 = (00 01 ** 03)
        ; mm5 = (** 05 ** 07)
    
        movq        mm2, mm1                          ; mm2 = (00 01 ** 03)
        pslld       mm1, WORD_BIT                     ; mm1 = (-- 00 -- **)
        psrad       mm1, (WORD_BIT - CONST_BITS - 2)  ; mm1 = tmp10[col0 ****]
    
        pand        mm2, mm7                          ; mm2 = (-- 01 -- 03)
        pand        mm5, mm7                          ; mm5 = (-- 05 -- 07)
        psrad       mm2, (WORD_BIT - CONST_BITS - 2)  ; mm2 = tmp10[col1 col3]
        psrad       mm5, (WORD_BIT - CONST_BITS - 2)  ; mm5 = tmp10[col5 col7]
    
        ; -- Final output stage
    
        movq        mm3, mm1
        paddd       mm1, mm4                ; mm1 = data0[col0 ****] = (A0 **)
        psubd       mm3, mm4                ; mm3 = data1[col0 ****] = (B0 **)
        punpckldq   mm1, mm3                ; mm1 = (A0 B0)
    
        movq        mm7, [GOTOFF(ebx, PD_DESCALE_P1_2)]  ; mm7 = [PD_DESCALE_P1_2]
    
        movq        mm4, mm2
        movq        mm3, mm5
        paddd       mm2, mm0                ; mm2 = data0[col1 col3] = (A1 A3)
        paddd       mm5, mm6                ; mm5 = data0[col5 col7] = (A5 A7)
        psubd       mm4, mm0                ; mm4 = data1[col1 col3] = (B1 B3)
        psubd       mm3, mm6                ; mm3 = data1[col5 col7] = (B5 B7)
    
        paddd       mm1, mm7
        psrad       mm1, DESCALE_P1_2
    
        paddd       mm2, mm7
        paddd       mm5, mm7
        psrad       mm2, DESCALE_P1_2
        psrad       mm5, DESCALE_P1_2
        paddd       mm4, mm7
        paddd       mm3, mm7
        psrad       mm4, DESCALE_P1_2
        psrad       mm3, DESCALE_P1_2
    
        ; ---- Pass 2: process rows, store into output array.
    
        mov         edi, JSAMPARRAY [output_buf(ebp)]  ; (JSAMPROW *)
        mov         eax, JDIMENSION [output_col(ebp)]
    
        ; | input:| result:|
        ; | A0 B0 |        |
        ; | A1 B1 | C0 C1  |
        ; | A3 B3 | D0 D1  |
        ; | A5 B5 |        |
        ; | A7 B7 |        |
    
        ; -- Odd part
    
        packssdw    mm2, mm4                ; mm2 = (A1 A3 B1 B3)
        packssdw    mm5, mm3                ; mm5 = (A5 A7 B5 B7)
        pmaddwd     mm2, [GOTOFF(ebx, PW_F362_MF127)]
        pmaddwd     mm5, [GOTOFF(ebx, PW_F085_MF072)]
    
        paddd       mm2, mm5                ; mm2 = tmp0[row0 row1]
    
        ; -- Even part
    
        pslld       mm1, (CONST_BITS + 2)   ; mm1 = tmp10[row0 row1]
    
        ; -- Final output stage
    
        movq        mm0, [GOTOFF(ebx, PD_DESCALE_P2_2)]  ; mm0 = [PD_DESCALE_P2_2]
    
        movq        mm6, mm1
        paddd       mm1, mm2                ; mm1 = data0[row0 row1] = (C0 C1)
        psubd       mm6, mm2                ; mm6 = data1[row0 row1] = (D0 D1)
    
        paddd       mm1, mm0
        paddd       mm6, mm0
        psrad       mm1, DESCALE_P2_2
        psrad       mm6, DESCALE_P2_2
    
        movq        mm7, mm1                ; transpose coefficients
        punpckldq   mm1, mm6                ; mm1 = (C0 D0)
        punpckhdq   mm7, mm6                ; mm7 = (C1 D1)
    
        packssdw    mm1, mm7                ; mm1 = (C0 D0 C1 D1)
        packsswb    mm1, mm1                ; mm1 = (C0 D0 C1 D1 C0 D0 C1 D1)
        paddb       mm1, [GOTOFF(ebx, PB_CENTERJSAMP)]
    
        movd        ecx, mm1
        movd        ebx, mm1                ; ebx = (C0 D0 C1 D1)
        shr         ecx, 2 * BYTE_BIT       ; ecx = (C1 D1 -- --)
    
        mov         edx, JSAMPROW [edi + 0 * SIZEOF_JSAMPROW]
        mov         esi, JSAMPROW [edi + 1 * SIZEOF_JSAMPROW]
        mov         word [edx + eax * SIZEOF_JSAMPLE], bx
        mov         word [esi + eax * SIZEOF_JSAMPLE], cx
    
        emms                                ; empty MMX state
    
        pop         edi
        pop         esi
    ;   pop         edx                     ; need not be preserved
    ;   pop         ecx                     ; need not be preserved
        pop         ebx
        pop         ebp
        ret
    
    ; For some reason, the OS X linker does not honor the request to align the
    ; segment unless we do this.
        align       32