📄 idctref.c
字号:
/* idctref_miha.c, Inverse Discrete Fourier Transform, double precision *//*************************************************************/
/* */
/* x87 hand-optimized assembly by Miha Peternel */
/* 27.11. - 20.1.2001 */
/* */
/* You are free to use this code in your project if: */
/* - no changes are made to this message */
/* - any changes to this code are publicly available */
/* - your project documentation contains the following text: */
/* "This software contains fast high-quality IDCT decoder */
/* by Miha Peternel." */
/* */
/*************************************************************/
/* Perform IEEE 1180 reference (64-bit floating point, separable 8x1 * direct matrix multiply) Inverse Discrete Cosine Transform*/
#define ModelX 123 // enable C-level optimizations by Miha Peternel/* Here we use math.h to generate constants. Compiler results may vary a little */#include <math.h>#define M_PI 3.1415926535897932384626433832795const static double HALF = 0.5;
/* private data */
static short iclip[1024+1024]; /* clipping table */
static short *iclp;
/* cosine transform matrix for 8x1 IDCT */static double c[8][8];/* initialize DCT coefficient matrix */void Initialize_REF_IDCT(){ int freq, time, i; double scale; for (freq=0; freq < 8; freq++) { scale = (freq == 0) ? sqrt(0.125) : 0.5; for (time=0; time<8; time++) c[freq][time] = scale*cos((M_PI/8.0)*freq*(time + 0.5)); }
#ifdef ModelX iclp = iclip+1024;
for (i= -1024; i<1024; i++)
iclp[i] = (i<-256) ? -256 : ((i>255) ? 255 : i);
#endif
}
void REF_IDCT(short *block){ double tmp[64];
double rnd[64];
int int0, int1, int2, int3, int4, int5, int6, int7;
unsigned short fpold;
unsigned short fpnew;
int *b = (int *) block;
if( !(b[0]|(b[31]&~0x10000)) )
{
if( b[ 1]|b[ 2]|b[ 3]|b[ 4]|b[ 5]|b[ 6] )
goto normal;
if( b[ 7]|b[ 8]|b[ 9]|b[10]|b[11]|b[12] )
goto normal;
if( b[13]|b[14]|b[15]|b[16]|b[17]|b[18] )
goto normal;
if( b[19]|b[20]|b[21]|b[22]|b[23]|b[24] )
goto normal;
if( b[25]|b[26]|b[27]|b[28]|b[29]|b[30] )
goto normal;
b[31]=0;
return;
}
normal:
__asm
{
// do the IDCT
mov esi,[block]
lea eax,[c]
lea edi,[tmp]
//mov ebx,8
mov ebx,8 // 0x77000000 // 8
align 16
__col1:
movzx edx,[esi+1*2]
mov ecx,[esi+2*2]
or edx,[esi+4*2]
or ecx,[esi+6*2]
or edx,ecx
//mov ecx,8
mov ecx,8/2 // 0x77000000 // 8
jnz __row1
fild word ptr [esi+0*2]
fmul qword ptr [eax+0*8*8]
fst qword ptr [edi+0*8]
fst qword ptr [edi+1*8]
fst qword ptr [edi+2*8]
fst qword ptr [edi+3*8]
fst qword ptr [edi+4*8]
fst qword ptr [edi+5*8]
fst qword ptr [edi+6*8]
fstp qword ptr [edi+7*8]
add edi,8*8
jmp __next1
align 16
__row1:
fild word ptr [esi+0*2]
fmul qword ptr [eax+0*8*8]
fild word ptr [esi+1*2]
fmul qword ptr [eax+1*8*8]
fadd
fild word ptr [esi+2*2]
fmul qword ptr [eax+2*8*8]
fadd
fild word ptr [esi+3*2]
fmul qword ptr [eax+3*8*8]
fadd
fild word ptr [esi+4*2]
fmul qword ptr [eax+4*8*8]
fadd
fild word ptr [esi+5*2]
fmul qword ptr [eax+5*8*8]
fadd
fild word ptr [esi+6*2]
fmul qword ptr [eax+6*8*8]
fadd
fild word ptr [esi+7*2]
fmul qword ptr [eax+7*8*8]
fadd
fild word ptr [esi+0*2]
fmul qword ptr [eax+0*8*8+8]
fild word ptr [esi+1*2]
fmul qword ptr [eax+1*8*8+8]
fadd
fild word ptr [esi+2*2]
fmul qword ptr [eax+2*8*8+8]
fadd
fild word ptr [esi+3*2]
fmul qword ptr [eax+3*8*8+8]
fadd
fild word ptr [esi+4*2]
fmul qword ptr [eax+4*8*8+8]
fadd
fild word ptr [esi+5*2]
fmul qword ptr [eax+5*8*8+8]
fadd
fild word ptr [esi+6*2]
fmul qword ptr [eax+6*8*8+8]
fadd
fild word ptr [esi+7*2]
fmul qword ptr [eax+7*8*8+8]
fadd
add eax,8*2
fxch st(1)
fstp qword ptr [edi]//
fstp qword ptr [edi+8]
add edi,8*2
dec ecx
jnz __row1
add eax,-8*8
//align 16
__next1:
add esi,+8*2
//dec ebx
sub ebx,0x80000001 // add ebx,ebx
js __col1
//align 16
test ebx,ebx // align jump &| redo flags
jnz __col1
lea esi,[tmp]
lea eax,[c]
lea edi,[rnd]
//mov edi,[block]
fld qword ptr [HALF]
mov ebx,8
__row2:
mov ecx,8/2
align 16
__col2:
fld qword ptr [esi+0*8*8]
fmul qword ptr [eax+0*8*8]
fld qword ptr [esi+1*8*8]
fmul qword ptr [eax+1*8*8]
fadd
fld qword ptr [esi+2*8*8]
fmul qword ptr [eax+2*8*8]
fadd
fld qword ptr [esi+3*8*8]
fmul qword ptr [eax+3*8*8]
fadd
fld qword ptr [esi+4*8*8]
fmul qword ptr [eax+4*8*8]
fadd
fld qword ptr [esi+5*8*8]
fmul qword ptr [eax+5*8*8]
fadd
fld qword ptr [esi+6*8*8]
fmul qword ptr [eax+6*8*8]
fadd
fld qword ptr [esi+7*8*8]
fmul qword ptr [eax+7*8*8]
fadd
fadd st(0),st(1)
fxch st(1)
fld qword ptr [esi+0*8*8]
fmul qword ptr [eax+0*8*8+8]
fld qword ptr [esi+1*8*8]
fmul qword ptr [eax+1*8*8+8]
fadd
fld qword ptr [esi+2*8*8]
fmul qword ptr [eax+2*8*8+8]
fadd
fld qword ptr [esi+3*8*8]
fmul qword ptr [eax+3*8*8+8]
fadd
fld qword ptr [esi+4*8*8]
fmul qword ptr [eax+4*8*8+8]
fadd
fld qword ptr [esi+5*8*8]
fmul qword ptr [eax+5*8*8+8]
fadd
fld qword ptr [esi+6*8*8]
fmul qword ptr [eax+6*8*8+8]
fadd
fld qword ptr [esi+7*8*8]
fmul qword ptr [eax+7*8*8+8]
fadd
fadd st(0),st(1)
add eax,8*2
fxch st(2)
fstp qword ptr [edi]
fxch st(1)
fstp qword ptr [edi+8*8]
add edi,8*8*2
dec ecx
jnz __col2
add eax,-8*8
add esi,+8
add edi,8-8*8*8
sub ebx,0x80000001
js __row2
//align 16
test ebx,ebx // align jump &| redo flags
jnz __row2
ffree st(0) // bye bye 0.5
// set x87 to floor mode
fstcw [fpold]
movzx eax, [fpold]
or eax, 0x0400 // round down - floor
mov [fpnew], ax
fldcw [fpnew]
// now floor the damn array
lea esi, [rnd]
mov edi, [block]
mov ebx, -256 // clip min
mov edx, +255 // clip max
mov ecx, 8
align 16
__floor:
fld qword ptr [esi+0*8]
fistp dword ptr [int0]
mov eax,[int0]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+1*8]
fistp dword ptr [int1]
mov word ptr [edi+0*2],ax
mov eax,[int1]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+2*8]
fistp dword ptr [int2]
mov word ptr [edi+1*2],ax
mov eax,[int2]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+3*8]
fistp dword ptr [int3]
mov word ptr [edi+2*2],ax
mov eax,[int3]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+4*8]
fistp dword ptr [int4]
mov word ptr [edi+3*2],ax
mov eax,[int4]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+5*8]
fistp dword ptr [int5]
mov word ptr [edi+4*2],ax
mov eax,[int5]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+6*8]
fistp dword ptr [int6]
mov word ptr [edi+5*2],ax
mov eax,[int6]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
fld qword ptr [esi+7*8]
fistp dword ptr [int7]
mov word ptr [edi+6*2],ax
mov eax,[int7]
cmp eax,ebx
cmovl eax,ebx
cmp eax,edx
cmovg eax,edx
mov word ptr [edi+7*2],ax
add esi, 8*8
add edi, 8*2
//dec ecx
sub ecx,0x80000001
js __floor
//align 16
test ecx,ecx // align jump &| redo flags
jnz __floor
// set x87 to default mode
fldcw [fpold]
};}⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -