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Merge pull request #2179 from sunheehnus/bitops-read

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bitops.c/redisPopcount: optimization in loop
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Salvatore Sanfilippo 2014-12-09 12:46:15 +01:00
commit 87f1e27b27
1 changed files with 21 additions and 9 deletions
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30
src/bitops.c
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@ -70,16 +70,19 @@ size_t redisPopcount(void *s, long count) {
count--;
}
/* Count bits 16 bytes at a time */
/* Count bits 28 bytes at a time */
p4 = (uint32_t*)p;
while(count>=16) {
uint32_t aux1, aux2, aux3, aux4;
while(count>=28) {
uint32_t aux1, aux2, aux3, aux4, aux5, aux6, aux7;
aux1 = *p4++;
aux2 = *p4++;
aux3 = *p4++;
aux4 = *p4++;
count -= 16;
aux5 = *p4++;
aux6 = *p4++;
aux7 = *p4++;
count -= 28;
aux1 = aux1 - ((aux1 >> 1) & 0x55555555);
aux1 = (aux1 & 0x33333333) + ((aux1 >> 2) & 0x33333333);
@ -89,10 +92,19 @@ size_t redisPopcount(void *s, long count) {
aux3 = (aux3 & 0x33333333) + ((aux3 >> 2) & 0x33333333);
aux4 = aux4 - ((aux4 >> 1) & 0x55555555);
aux4 = (aux4 & 0x33333333) + ((aux4 >> 2) & 0x33333333);
bits += ((((aux1 + (aux1 >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24) +
((((aux2 + (aux2 >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24) +
((((aux3 + (aux3 >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24) +
((((aux4 + (aux4 >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24);
aux5 = aux5 - ((aux5 >> 1) & 0x55555555);
aux5 = (aux5 & 0x33333333) + ((aux5 >> 2) & 0x33333333);
aux6 = aux6 - ((aux6 >> 1) & 0x55555555);
aux6 = (aux6 & 0x33333333) + ((aux6 >> 2) & 0x33333333);
aux7 = aux7 - ((aux7 >> 1) & 0x55555555);
aux7 = (aux7 & 0x33333333) + ((aux7 >> 2) & 0x33333333);
bits += ((((aux1 + (aux1 >> 4)) & 0x0F0F0F0F) +
((aux2 + (aux2 >> 4)) & 0x0F0F0F0F) +
((aux3 + (aux3 >> 4)) & 0x0F0F0F0F) +
((aux4 + (aux4 >> 4)) & 0x0F0F0F0F) +
((aux5 + (aux5 >> 4)) & 0x0F0F0F0F) +
((aux6 + (aux6 >> 4)) & 0x0F0F0F0F) +
((aux7 + (aux7 >> 4)) & 0x0F0F0F0F))* 0x01010101) >> 24;
}
/* Count the remaining bytes. */
p = (unsigned char*)p4;
@ -348,7 +360,7 @@ void bitopCommand(redisClient *c) {
* can take a fast path that performs much better than the
* vanilla algorithm. */
j = 0;
if (minlen && numkeys <= 16) {
if (minlen >= sizeof(unsigned long)*4 && numkeys <= 16) {
unsigned long *lp[16];
unsigned long *lres = (unsigned long*) res;