1 2 #include <stdio.h> 3 4 typedef unsigned long long int ULong; 5 6 extern ULong lahf_1 ( void ); 7 asm("\n" 8 "lahf_1:\n" 9 "\tpushq $0\n" 10 "\tpopfq\n" 11 "\tmovabsq $0xFFFFFFFFFFFFFFFF, %rax\n" 12 "\tmovabsq $0x8765432112345678, %rdx\n" 13 "\tsubq %rax, %rdx\n" 14 "\t.byte 0x9F\n" /* lahf */ 15 "\tret\n" 16 ); 17 18 extern ULong lahf_0 ( void ); 19 asm("\n" 20 "lahf_0:\n" 21 "\tpushq $0\n" 22 "\tpopfq\n" 23 "\tmovabsq $0x0, %rax\n" 24 "\tmovabsq $0x8765432112345678, %rdx\n" 25 "\tsubq %rax, %rdx\n" 26 "\t.byte 0x9F\n" /* lahf */ 27 "\tret\n" 28 ); 29 30 extern ULong sahf_then_lahf ( ULong ); 31 asm("\n" 32 "sahf_then_lahf:\n" 33 "\tmovq %rdi, %rax\n" 34 "\t.byte 0x9E\n" /* sahf */ 35 "\tmovabsq $0, %rax\n" 36 "\t.byte 0x9F\n" /* lahf */ 37 "\tret\n" 38 ); 39 40 int main ( void ) 41 { 42 ULong i; 43 printf("0x%llx\n", lahf_0()); 44 printf("0x%llx\n", lahf_1()); 45 for (i = 0; i < 255; i++) { 46 ULong x = sahf_then_lahf(i << 8); 47 printf("%llx -> %llx\n", i, x); 48 } 49 return 0; 50 } 51
