Bill Yi | 4e213d5 | 2015-06-23 13:53:11 -0700 | [diff] [blame] | 1 | /* 16-bit signed integer dot product |
| 2 | * SSE2 version |
| 3 | * Copyright 2004 Phil Karn |
| 4 | * May be used under the terms of the GNU Lesser General Public License (LGPL) |
| 5 | */ |
| 6 | #define _XOPEN_SOURCE 600 |
| 7 | #include <stdlib.h> |
| 8 | #include <memory.h> |
| 9 | #include "fec.h" |
| 10 | |
| 11 | struct dotprod { |
| 12 | int len; /* Number of coefficients */ |
| 13 | |
| 14 | /* On a SSE2 machine, these hold 8 copies of the coefficients, |
| 15 | * preshifted by 0,1,..7 words to meet all possible input data |
| 16 | * alignments (see Intel ap559 on MMX dot products). |
| 17 | */ |
| 18 | signed short *coeffs[8]; |
| 19 | }; |
| 20 | |
| 21 | long dotprod_sse2_assist(signed short *a,signed short *b,int cnt); |
| 22 | |
| 23 | /* Create and return a descriptor for use with the dot product function */ |
| 24 | void *initdp_sse2(signed short coeffs[],int len){ |
| 25 | struct dotprod *dp; |
| 26 | int i,j,blksize; |
| 27 | |
| 28 | if(len == 0) |
| 29 | return NULL; |
| 30 | |
| 31 | dp = (struct dotprod *)calloc(1,sizeof(struct dotprod)); |
| 32 | dp->len = len; |
| 33 | |
| 34 | /* Make 8 copies of coefficients, one for each data alignment, |
| 35 | * each aligned to 16-byte boundary |
| 36 | */ |
| 37 | for(i=0;i<8;i++){ |
| 38 | blksize = (1+(len+i-1)/8) * 8*sizeof(signed short); |
| 39 | posix_memalign((void **)&dp->coeffs[i],16,blksize); |
| 40 | memset(dp->coeffs[i],0,blksize); |
| 41 | for(j=0;j<len;j++) |
| 42 | dp->coeffs[i][j+i] = coeffs[j]; |
| 43 | } |
| 44 | return (void *)dp; |
| 45 | } |
| 46 | |
| 47 | |
| 48 | /* Free a dot product descriptor created earlier */ |
| 49 | void freedp_sse2(void *p){ |
| 50 | struct dotprod *dp = (struct dotprod *)p; |
| 51 | int i; |
| 52 | |
| 53 | for(i=0;i<8;i++) |
| 54 | if(dp->coeffs[i] != NULL) |
| 55 | free(dp->coeffs[i]); |
| 56 | free(dp); |
| 57 | } |
| 58 | |
| 59 | /* Compute a dot product given a descriptor and an input array |
| 60 | * The length is taken from the descriptor |
| 61 | */ |
| 62 | long dotprod_sse2(void *p,signed short a[]){ |
| 63 | struct dotprod *dp = (struct dotprod *)p; |
| 64 | int al; |
| 65 | signed short *ar; |
| 66 | |
| 67 | ar = (signed short *)((int)a & ~15); |
| 68 | al = a - ar; |
| 69 | |
| 70 | /* Call assembler routine to do the work, passing number of 8-word blocks */ |
| 71 | return dotprod_sse2_assist(ar,dp->coeffs[al],(dp->len+al-1)/8+1); |
| 72 | } |