#include typedef unsigned long long int ULong; typedef unsigned int UInt; __attribute__((noinline)) void do_lzcnt64 ( /*OUT*/UInt* flags, /*OUT*/ULong* res, ULong arg ) { ULong block[3] = { arg, 0ULL, 0ULL }; __asm__ __volatile__( "movabsq $0x5555555555555555, %%r11" "\n\t" "lzcntq 0(%0), %%r11" "\n\t" "movq %%r11, 8(%0)" "\n\t" "pushfq" "\n\t" "popq %%r11" "\n\t" "movq %%r11, 16(%0)" "\n" : : "r"(&block[0]) : "r11","cc","memory" ); *res = block[1]; *flags = block[2] & 0x8d5; } __attribute__((noinline)) void do_lzcnt32 ( /*OUT*/UInt* flags, /*OUT*/ULong* res, ULong arg ) { ULong block[3] = { arg, 0ULL, 0ULL }; __asm__ __volatile__( "movabsq $0x5555555555555555, %%r11" "\n\t" "lzcntl 0(%0), %%r11d" "\n\t" "movq %%r11, 8(%0)" "\n\t" "pushfq" "\n\t" "popq %%r11" "\n\t" "movq %%r11, 16(%0)" "\n" : : "r"(&block[0]) : "r11","cc","memory" ); *res = block[1]; *flags = block[2] & 0x8d5; } __attribute__((noinline)) void do_lzcnt16 ( /*OUT*/UInt* flags, /*OUT*/ULong* res, ULong arg ) { ULong block[3] = { arg, 0ULL, 0ULL }; __asm__ __volatile__( "movabsq $0x5555555555555555, %%r11" "\n\t" "lzcntw 0(%0), %%r11w" "\n\t" "movq %%r11, 8(%0)" "\n\t" "pushfq" "\n\t" "popq %%r11" "\n\t" "movq %%r11, 16(%0)" "\n" : : "r"(&block[0]) : "r11","cc","memory" ); *res = block[1]; *flags = block[2] & 0x8d5; } int main ( void ) { ULong w; w = 0xFEDC192837475675ULL; while (1) { ULong res; UInt flags; do_lzcnt64(&flags, &res, w); printf("lzcntq %016llx -> %016llx %04x\n", w, res, flags); if (w == 0) break; w = ((w >> 2) | (w >> 1)) + (w / 17ULL); } w = 0xFEDC192837475675ULL; while (1) { ULong res; UInt flags; do_lzcnt32(&flags, &res, w); printf("lzcntl %016llx -> %016llx %04x\n", w, res, flags); if (w == 0) break; w = ((w >> 2) | (w >> 1)) + (w / 17ULL); } w = 0xFEDC192837475675ULL; while (1) { ULong res; UInt flags; do_lzcnt16(&flags, &res, w); printf("lzcntw %016llx -> %016llx %04x\n", w, res, flags); if (w == 0) break; w = ((w >> 2) | (w >> 1)) + (w / 17ULL); } return 0; }