fast_copy.c

<VC++视频音频开发>一书的光盘资料。

#include "postprocess_mmx.h"


void fast_copy(unsigned char *src, int src_stride,
                 unsigned char *dst, int dst_stride, 
                 int horizontal_size,   int vertical_size) {
	
	uint8_t *pmm1;
	uint8_t *pmm2;
	int x, y;

	#ifdef PP_SELF_CHECK
	int j, k;
	#endif
	
		pmm1 = src;
		pmm2 = dst;

		for (y=0; y<vertical_size; y++) {

			x = - horizontal_size / 8;

			__asm {
				push edi
				push ebx
				push ecx
				
				mov edi, x
				mov ebx, pmm1
				mov ecx, pmm2
			
			L123:                                         /*                                 */	
				movq   mm0, [ebx]                         /* mm0 = *pmm1                     */							
				movq   [ecx], mm0                         /* *pmm2 = mm0                     */							
				add   ecx, 8                              /* pmm2 +=8                        */
				#ifdef PREFETCH_ENABLE
				prefetcht0 32[ebx]                        /* prefetch ahead                  */							
				#endif
				add   ebx, 8                              /* pmm1 +=8                        */
				add   edi, 1                              /* increment loop counter          */
				jne    L123
				
				pop ecx
				pop ebx
				pop edi
				  
			};

			pmm1 += src_stride;
			
			pmm2 += dst_stride;
			

		}


	#ifdef PP_SELF_CHECK
	for (k=0; k<vertical_size; k++) {
		for (j=0; j<horizontal_size; j++) {
			if (dst[k*dst_stride + j] != src[k*src_stride + j]) {
				printf("problem with MMX fast copy - Y\n");
			}
		}
	}
	#endif

	__asm { 
		emms
	};

}