73 lines
1.9 KiB
C
73 lines
1.9 KiB
C
/* 16-bit signed integer dot product
|
|
* SSE2 version
|
|
* Copyright 2004 Phil Karn
|
|
* May be used under the terms of the GNU Lesser General Public License (LGPL)
|
|
*/
|
|
#define _XOPEN_SOURCE 600
|
|
#include <stdlib.h>
|
|
#include <memory.h>
|
|
#include "fec.h"
|
|
|
|
struct dotprod {
|
|
int len; /* Number of coefficients */
|
|
|
|
/* On a SSE2 machine, these hold 8 copies of the coefficients,
|
|
* preshifted by 0,1,..7 words to meet all possible input data
|
|
* alignments (see Intel ap559 on MMX dot products).
|
|
*/
|
|
signed short *coeffs[8];
|
|
};
|
|
|
|
long dotprod_sse2_assist(signed short *a,signed short *b,int cnt);
|
|
|
|
/* Create and return a descriptor for use with the dot product function */
|
|
void *initdp_sse2(signed short coeffs[],int len){
|
|
struct dotprod *dp;
|
|
int i,j,blksize;
|
|
|
|
if(len == 0)
|
|
return NULL;
|
|
|
|
dp = (struct dotprod *)calloc(1,sizeof(struct dotprod));
|
|
dp->len = len;
|
|
|
|
/* Make 8 copies of coefficients, one for each data alignment,
|
|
* each aligned to 16-byte boundary
|
|
*/
|
|
for(i=0;i<8;i++){
|
|
blksize = (1+(len+i-1)/8) * 8*sizeof(signed short);
|
|
posix_memalign((void **)&dp->coeffs[i],16,blksize);
|
|
memset(dp->coeffs[i],0,blksize);
|
|
for(j=0;j<len;j++)
|
|
dp->coeffs[i][j+i] = coeffs[j];
|
|
}
|
|
return (void *)dp;
|
|
}
|
|
|
|
|
|
/* Free a dot product descriptor created earlier */
|
|
void freedp_sse2(void *p){
|
|
struct dotprod *dp = (struct dotprod *)p;
|
|
int i;
|
|
|
|
for(i=0;i<8;i++)
|
|
if(dp->coeffs[i] != NULL)
|
|
free(dp->coeffs[i]);
|
|
free(dp);
|
|
}
|
|
|
|
/* Compute a dot product given a descriptor and an input array
|
|
* The length is taken from the descriptor
|
|
*/
|
|
long dotprod_sse2(void *p,signed short a[]){
|
|
struct dotprod *dp = (struct dotprod *)p;
|
|
int al;
|
|
signed short *ar;
|
|
|
|
ar = (signed short *)((int)a & ~15);
|
|
al = a - ar;
|
|
|
|
/* Call assembler routine to do the work, passing number of 8-word blocks */
|
|
return dotprod_sse2_assist(ar,dp->coeffs[al],(dp->len+al-1)/8+1);
|
|
}
|