quantize_mpeg_mmx.asm

这是一个压缩解压包,用C语言进行编程的,里面有详细的源代码.

  movq mm2, [ebx + 768 + ecx*8]
  pmulhw mm0, mm2               ; (level<<4 + inter_matrix[i]>>1) / inter_matrix[i]
  movq mm2, [ebx + 512 + 8*ecx + 8]
  psrlw mm2, 1
  paddw mm3, mm2
  movq mm2, [ebx + 768 + ecx*8 + 8]
  pmulhw mm3, mm2
  pmulhw mm0, mm7               ; mm0 = (mm0 / 2Q) >> 16
  pmulhw mm3, mm7               ;
  psrlw mm0, 1                  ; additional shift by 1 => 16 + 1 = 17
  psrlw mm3, 1
  paddw mm5, mm0                ; sum += mm0
  pxor mm0, mm1                 ; mm0 *= sign(mm0)
  paddw mm5, mm3                ;
  pxor mm3, mm4                 ;
  psubw mm0, mm1                ; undisplace
  psubw mm3, mm4
  movq [edi + 8*ecx], mm0
  movq [edi + 8*ecx + 8], mm3

  add ecx, 2
  cmp ecx, 16
  jnz near .loop

.done
  pmaddwd mm5, [mmx_one]
  movq mm0, mm5
  psrlq mm5, 32
  paddd mm0, mm5
  movd eax, mm0                 ; return sum

  pop ebx
  pop edi
  pop esi
  pop ecx

  ret

ALIGN 16
.q1loop
  movq mm0, [esi + 8*ecx]       ; mm0 = [1st]
  movq mm3, [esi + 8*ecx+ 8]
  pxor mm1, mm1                 ; mm1 = 0
  pxor mm4, mm4                 ;
  pcmpgtw mm1, mm0              ; mm1 = (0 > mm0)
  pcmpgtw mm4, mm3              ;
  pxor mm0, mm1                 ; mm0 = |mm0|
  pxor mm3, mm4                 ;
  psubw mm0, mm1                ; displace
  psubw mm3, mm4                ;
  psllw mm0, 4
  psllw mm3, 4
  movq mm2, [ebx + 512 + 8*ecx]
  psrlw mm2, 1
  paddw mm0, mm2
  movq mm2, [ebx + 768 + ecx*8]
  pmulhw mm0, mm2               ; (level<<4 + inter_matrix[i]>>1) / inter_matrix[i]
  movq mm2, [ebx + 512 + 8*ecx + 8]
  psrlw mm2, 1
  paddw mm3, mm2
  movq mm2, [ebx + 768 + ecx*8 + 8]
  pmulhw mm3, mm2
  psrlw mm0, 1                  ; mm0 >>= 1   (/2)
  psrlw mm3, 1                  ;
  paddw mm5, mm0                ; sum += mm0
  pxor mm0, mm1                 ; mm0 *= sign(mm0)
  paddw mm5, mm3                ;
  pxor mm3, mm4                 ;
  psubw mm0, mm1                ; undisplace
  psubw mm3, mm4
  movq [edi + 8*ecx], mm0
  movq [edi + 8*ecx + 8], mm3

  add ecx, 2
  cmp ecx, 16
  jnz near .q1loop

  jmp .done

ALIGN 16
.q2loop
  movq mm0, [esi + 8*ecx]       ; mm0 = [1st]
  movq mm3, [esi + 8*ecx+ 8]
  pxor mm1, mm1                 ; mm1 = 0
  pxor mm4, mm4                 ;
  pcmpgtw mm1, mm0              ; mm1 = (0 > mm0)
  pcmpgtw mm4, mm3              ;
  pxor mm0, mm1                 ; mm0 = |mm0|
  pxor mm3, mm4                 ;
  psubw mm0, mm1                ; displace
  psubw mm3, mm4                ;
  psllw mm0, 4
  psllw mm3, 4
  movq mm2, [ebx + 512 + 8*ecx]
  psrlw mm2, 1
  paddw mm0, mm2
  movq mm2, [ebx + 768 + ecx*8]
  pmulhw mm0, mm2               ; (level<<4 + inter_matrix[i]>>1) / inter_matrix[i]
  movq mm2, [ebx + 512 + 8*ecx + 8]
  psrlw mm2, 1
  paddw mm3, mm2
  movq mm2, [ebx + 768 + ecx*8 + 8]
  pmulhw mm3, mm2
  psrlw mm0, 2                  ; mm0 >>= 1   (/2)
  psrlw mm3, 2                  ;
  paddw mm5, mm0                ; sum += mm0
  pxor mm0, mm1                 ; mm0 *= sign(mm0)
  paddw mm5, mm3                ;
  pxor mm3, mm4                 ;
  psubw mm0, mm1                ; undisplace
  psubw mm3, mm4
  movq [edi + 8*ecx], mm0
  movq [edi + 8*ecx + 8], mm3

  add ecx, 2
  cmp ecx, 16
  jnz near .q2loop

  jmp .done
.endfunc


;-----------------------------------------------------------------------------
;
; uint32_t dequant_mpeg_intra_mmx(int16_t *data,
;                                 const int16_t const *coeff,
;                                 const uint32_t quant,
;                                 const uint32_t dcscalar,
;                                 const uint16_t *mpeg_matrices);
;
;-----------------------------------------------------------------------------

  ;   Note: in order to saturate 'easily', we pre-shift the quantifier
  ; by 4. Then, the high-word of (coeff[]*matrix[i]*quant) are used to
  ; build a saturating mask. It is non-zero only when an overflow occured.
  ; We thus avoid packing/unpacking toward double-word.
  ; Moreover, we perform the mult (matrix[i]*quant) first, instead of, e.g.,
  ; (coeff[i]*matrix[i]). This is less prone to overflow if coeff[] are not
  ; checked. Input ranges are: coeff in [-127,127], inter_matrix in [1..255],a
  ; and quant in [1..31].
  ;
  ; The original loop is:
  ;
%if 0
  movq mm0, [ecx+8*eax + 8*16]   ; mm0 = coeff[i]
  pxor mm1, mm1
  pcmpgtw mm1, mm0
  pxor mm0, mm1     ; change sign if negative
  psubw mm0, mm1    ; -> mm0 = abs(coeff[i]), mm1 = sign of coeff[i]

  movq mm2, mm7     ; mm2 = quant
  pmullw mm2, [ebx + 8*eax + 8*16 ]  ; matrix[i]*quant.

  movq mm6, mm2
  pmulhw mm2, mm0   ; high of coeff*(matrix*quant)  (should be 0 if no overflow)
  pmullw mm0, mm6   ; low  of coeff*(matrix*quant)

  pxor mm5, mm5
  pcmpgtw mm2, mm5  ; otherflow?
  psrlw mm2, 5      ; =0 if no clamp, 2047 otherwise
  psrlw mm0, 5
  paddw mm0, mm1    ; start restoring sign
  por mm0, mm2      ; saturate to 2047 if needed
  pxor mm0, mm1     ; finish negating back

  movq [edx + 8*eax + 8*16], mm0   ; data[i]
  add eax, 1
%endif

  ;********************************************************************

ALIGN 16
dequant_mpeg_intra_mmx:

  push ebx

  mov edx, [esp + 4 + 4]  ; data
  mov ecx, [esp + 4 + 8]  ; coeff
  mov eax, [esp + 4 + 12] ; quant
  mov ebx, [esp + 4 + 20] ; mpeg_quant_matrices

  movq mm7, [mmx_mul_quant  + eax*8 - 8]
  mov eax, -16      ; to keep ALIGNed, we regularly process coeff[0]
  psllw mm7, 2      ; << 2. See comment.
  pxor mm6, mm6     ; this is a NOP

ALIGN 16
.loop
  movq mm0, [ecx+8*eax + 8*16]   ; mm0 = c  = coeff[i]
  movq mm3, [ecx+8*eax + 8*16 +8]; mm3 = c' = coeff[i+1]
  pxor mm1, mm1
  pxor mm4, mm4
  pcmpgtw mm1, mm0  ; mm1 = sgn(c)
  movq mm2, mm7     ; mm2 = quant

  pcmpgtw mm4, mm3  ; mm4 = sgn(c')
  pmullw mm2,  [ebx + 8*eax + 8*16 ]  ; matrix[i]*quant

  pxor mm0, mm1     ; negate if negative
  pxor mm3, mm4     ; negate if negative

  psubw mm0, mm1
  psubw mm3, mm4

 ; we're short on register, here. Poor pairing...

  movq mm5, mm2
  pmullw mm2, mm0   ; low  of coeff*(matrix*quant)

  pmulhw mm0, mm5   ; high of coeff*(matrix*quant)
  movq mm5, mm7     ; mm2 = quant

  pmullw mm5,  [ebx + 8*eax + 8*16 +8]  ; matrix[i+1]*quant

  movq mm6, mm5
  add eax,2   ; z-flag will be tested later

  pmullw mm6, mm3   ; low  of coeff*(matrix*quant)
  pmulhw mm3, mm5   ; high of coeff*(matrix*quant)

  pcmpgtw mm0, [zero]
  paddusw mm2, mm0
  psrlw mm2, 5

  pcmpgtw mm3, [zero]
  paddusw mm6, mm3
  psrlw mm6, 5

  pxor mm2, mm1  ; start negating back
  pxor mm6, mm4  ; start negating back

  psubusw mm1, mm0
  psubusw mm4, mm3

  psubw mm2, mm1 ; finish negating back
  psubw mm6, mm4 ; finish negating back

  movq [edx + 8*eax + 8*16   -2*8   ], mm2   ; data[i]
  movq [edx + 8*eax + 8*16   -2*8 +8], mm6   ; data[i+1]

 jnz        near .loop

    ; deal with DC
  movd mm0, [ecx]
  pmullw mm0, [esp + 4 + 16]  ; dcscalar
  movq mm2, [mmx_32767_minus_2047]
  paddsw mm0, mm2
  psubsw mm0, mm2
  movq mm2, [mmx_32768_minus_2048]
  psubsw mm0, mm2
  paddsw mm0, mm2
  movd eax, mm0
  mov [edx], ax

  xor eax, eax
  
  pop ebx

  ret
.endfunc

;-----------------------------------------------------------------------------
;
; uint32_t dequant_mpeg_inter_mmx(int16_t * data,
;                                 const int16_t * const coeff,
;                                 const uint32_t quant,
;                                 const uint16_t *mpeg_matrices);
;
;-----------------------------------------------------------------------------

    ; Note:  We use (2*c + sgn(c) - sgn(-c)) as multiplier
    ; so we handle the 3 cases: c<0, c==0, and c>0 in one shot.
    ; sgn(x) is the result of 'pcmpgtw 0,x':  0 if x>=0, -1 if x<0.
    ; It's mixed with the extraction of the absolute value.

ALIGN 16
dequant_mpeg_inter_mmx:

  push ebx

  mov edx, [esp + 4 + 4]        ; data
  mov ecx, [esp + 4 + 8]        ; coeff
  mov eax, [esp + 4 + 12]        ; quant
  mov ebx, [esp + 4 + 16]		   ; mpeg_quant_matrices

  movq mm7, [mmx_mul_quant  + eax*8 - 8]
  mov eax, -16
  paddw mm7, mm7    ; << 1
  pxor mm6, mm6     ; mismatch sum

ALIGN 16
.loop
  movq mm0, [ecx+8*eax + 8*16   ]   ; mm0 = coeff[i]
  movq mm2, [ecx+8*eax + 8*16 +8]   ; mm2 = coeff[i+1]
  add eax, 2

  pxor mm1, mm1
  pxor mm3, mm3
  pcmpgtw mm1, mm0  ; mm1 = sgn(c)    (preserved)
  pcmpgtw mm3, mm2  ; mm3 = sgn(c')   (preserved)
  paddsw mm0, mm1   ; c += sgn(c)
  paddsw mm2, mm3   ; c += sgn(c')
  paddw mm0, mm0    ; c *= 2
  paddw mm2, mm2    ; c'*= 2

  pxor mm4, mm4
  pxor mm5, mm5
  psubw mm4, mm0    ; -c
  psubw mm5, mm2    ; -c'
  psraw mm4, 16     ; mm4 = sgn(-c)
  psraw mm5, 16     ; mm5 = sgn(-c')
  psubsw mm0, mm4   ; c  -= sgn(-c)
  psubsw mm2, mm5   ; c' -= sgn(-c')
  pxor mm0, mm1     ; finish changing sign if needed
  pxor mm2, mm3     ; finish changing sign if needed

    ; we're short on register, here. Poor pairing...

  movq mm4, mm7     ; (matrix*quant)
  pmullw mm4,  [ebx + 512 + 8*eax + 8*16 -2*8]
  movq mm5, mm4
  pmulhw mm5, mm0   ; high of c*(matrix*quant)
  pmullw mm0, mm4   ; low  of c*(matrix*quant)

  movq mm4, mm7     ; (matrix*quant)
  pmullw mm4,  [ebx + 512 + 8*eax + 8*16 -2*8 + 8]

  pcmpgtw mm5, [zero]
  paddusw mm0, mm5
  psrlw mm0, 5
  pxor mm0, mm1     ; start restoring sign
  psubusw mm1, mm5

  movq mm5, mm4
  pmulhw mm5, mm2   ; high of c*(matrix*quant)
  pmullw mm2, mm4   ; low  of c*(matrix*quant)
  psubw mm0, mm1    ; finish restoring sign

  pcmpgtw mm5, [zero]
  paddusw mm2, mm5
  psrlw mm2, 5
  pxor mm2, mm3     ; start restoring sign
  psubusw mm3, mm5
  psubw mm2, mm3    ; finish restoring sign

  pxor mm6, mm0     ; mismatch control
  movq [edx + 8*eax + 8*16 -2*8   ], mm0   ; data[i]
  pxor mm6, mm2     ; mismatch control
  movq [edx + 8*eax + 8*16 -2*8 +8], mm2   ; data[i+1]

  jnz near .loop

  ; mismatch control

  movq mm0, mm6
  psrlq mm0, 48
  movq mm1, mm6
  movq mm2, mm6
  psrlq mm1, 32
  pxor mm6, mm0
  psrlq mm2, 16
  pxor mm6, mm1
  pxor mm6, mm2
  movd eax, mm6
  and eax, 1
  xor eax, 1
  xor word [edx + 2*63], ax

  xor eax, eax
  
  pop ebx

  ret
.endfunc