過剰なCMPの秘密、またはなぜヴォロドカが口ひげを剃ったのか？

#include <stdio.h> typedef unsigned long long BN_WORD; int Add(BN_WORD c[8], BN_WORD a[8], BN_WORD b[8]) { c[0] = a[0] + b[0]; c[1] = a[1] + b[1] + (c[0] < a[0]); c[2] = a[2] + b[2] + (c[1] < a[1]); c[3] = a[3] + b[3] + (c[2] < a[2]); c[4] = a[4] + b[4] + (c[3] < a[3]); c[5] = a[5] + b[5] + (c[4] < a[4]); c[6] = a[6] + b[6] + (c[5] < a[5]); c[7] = a[7] + b[7] + (c[6] < a[6]); return (c[7] < a[7]); } int main(void) { int i; BN_WORD a[8], b[8], c[8], Carry; // ,   inline    Add   main int (*add)(BN_WORD c[8], BN_WORD a[8], BN_WORD b[8]) = Add; for( i=0; i<8; i++) { a[i] = b[i] = 0x8000000000000000; } Carry = add(c, a, b); //  for( i=0; i<8; ++i) { if (Carry!=1 || c[i]!=(i!=0)) { printf("Something wrong\n"); return 1; } } printf("Ok!\n", Carry); return 0; } 

 ?Add@@YAXQEA_K00@Z PROC ; Add, COMDAT ; Line 6 $LN3: mov QWORD PTR [rsp+8], rbx mov QWORD PTR [rsp+16], rdi ; Line 7 mov r10, QWORD PTR [rdx] ; Line 15 mov rdi, QWORD PTR [rsp+16] mov rbx, rdx add r10, QWORD PTR [r8] mov r11, r8 mov QWORD PTR [rcx], r10 cmp r10, QWORD PTR [rdx] mov r8, QWORD PTR [r8+8] adc r8, 0 add r8, QWORD PTR [rdx+8] mov QWORD PTR [rcx+8], r8 cmp r8, QWORD PTR [rdx+8] mov rdx, QWORD PTR [r11+16] adc rdx, 0 add rdx, QWORD PTR [rbx+16] mov QWORD PTR [rcx+16], rdx cmp rdx, QWORD PTR [rbx+16] mov rdx, QWORD PTR [r11+24] adc rdx, 0 add rdx, QWORD PTR [rbx+24] mov QWORD PTR [rcx+24], rdx cmp rdx, QWORD PTR [rbx+24] mov rdx, QWORD PTR [r11+32] adc rdx, 0 add rdx, QWORD PTR [rbx+32] mov QWORD PTR [rcx+32], rdx cmp rdx, QWORD PTR [rbx+32] mov rdx, QWORD PTR [r11+40] adc rdx, 0 add rdx, QWORD PTR [rbx+40] mov QWORD PTR [rcx+40], rdx cmp rdx, QWORD PTR [rbx+40] mov rdx, QWORD PTR [r11+48] adc rdx, 0 add rdx, QWORD PTR [rbx+48] mov QWORD PTR [rcx+48], rdx cmp rdx, QWORD PTR [rbx+48] mov rax, QWORD PTR [rbx+56] adc rax, QWORD PTR [r11+56] mov rbx, QWORD PTR [rsp+8] mov QWORD PTR [rcx+56], rax ret 0 ?Add@@YAXQEA_K00@Z ENDP ; Add _TEXT ENDS 

 #include <stdio.h> #include <windows.h> typedef unsigned long long BN_WORD; int Add(BN_WORD c[8], BN_WORD a[8], BN_WORD b[8]) { c[0] = a[0] + b[0]; c[1] = a[1] + b[1] + (c[0] < a[0]); c[2] = a[2] + b[2] + (c[1] < a[1]); c[3] = a[3] + b[3] + (c[2] < a[2]); c[4] = a[4] + b[4] + (c[3] < a[3]); c[5] = a[5] + b[5] + (c[4] < a[4]); c[6] = a[6] + b[6] + (c[5] < a[5]); c[7] = a[7] + b[7] + (c[6] < a[6]); return (c[7] < a[7]); } void ReadMem(__int64 pos, char *patch, int len) { DWORD my_id = GetCurrentProcessId(); HANDLE p_hand = OpenProcess(PROCESS_VM_READ | PROCESS_VM_OPERATION, NULL, my_id); if (ReadProcessMemory(p_hand, (LPDWORD)pos, patch, len, NULL)==0) { printf("Error %d read from memory\n", GetLastError()); } CloseHandle(p_hand); } void WriteMem(__int64 pos, char *patch, int len) { DWORD my_id = GetCurrentProcessId(); HANDLE p_hand = OpenProcess(PROCESS_VM_WRITE | PROCESS_VM_OPERATION, NULL, my_id); if (WriteProcessMemory(p_hand, (LPDWORD)pos, patch, len, NULL)==0) { printf("Error %d write to memory\n", GetLastError()); } CloseHandle(p_hand); } void udalit_usi(int pos, int size, int full_size) { char *mem = (char*)malloc(full_size-pos); __int64 pos_add = (__int64)Add; //       ReadMem(pos_add + pos, mem, full_size-pos); // ,    ,   size WriteMem(pos_add + pos, mem+size, full_size-pos-size); free(mem); } char *add_listing = " 00000000 ?Add@@YAHQEA_K00@Z PROC ; Add, COMDAT\n" " ; Line 7\n" " 00000000 $LN3:\n" " 00000000 48/ 89 5C 24 mov QWORD PTR [rsp+8], rbx\n" " 08\n" " 00000005 48/ 89 7C 24 mov QWORD PTR [rsp+16], rdi\n" " 10\n" " ; Line 8\n" " 0000000A 4C/ 8B 12 mov r10, QWORD PTR [rdx]\n" " ; Line 17\n" " 0000000D 48/ 8B 5C 24 mov rbx, QWORD PTR [rsp+8]\n" " 08\n" " 00000012 48/ 8B FA mov rdi, rdx\n" " 00000015 4D/ 03 10 add r10, QWORD PTR [r8]\n" " 00000018 4D/ 8B D8 mov r11, r8\n" " 0000001B 4C/ 89 11 mov QWORD PTR [rcx], r10\n" " 0000001E 4C/ 3B 12 cmp r10, QWORD PTR [rdx]\n" " 00000021 4D/ 8B 40 08 mov r8, QWORD PTR [r8+8]\n" " 00000025 49/ 83 D0 00 adc r8, 0\n" " 00000029 4C/ 03 42 08 add r8, QWORD PTR [rdx+8]\n" " 0000002D 4C/ 89 41 08 mov QWORD PTR [rcx+8], r8\n" " 00000031 4C/ 3B 42 08 cmp r8, QWORD PTR [rdx+8]\n" " 00000035 49/ 8B 53 10 mov rdx, QWORD PTR [r11+16]\n" " 00000039 48/ 83 D2 00 adc rdx, 0\n" " 0000003D 48/ 03 57 10 add rdx, QWORD PTR [rdi+16]\n" " 00000041 48/ 89 51 10 mov QWORD PTR [rcx+16], rdx\n" " 00000045 48/ 3B 57 10 cmp rdx, QWORD PTR [rdi+16]\n" " 00000049 49/ 8B 53 18 mov rdx, QWORD PTR [r11+24]\n" " 0000004D 48/ 83 D2 00 adc rdx, 0\n" " 00000051 48/ 03 57 18 add rdx, QWORD PTR [rdi+24]\n" " 00000055 48/ 89 51 18 mov QWORD PTR [rcx+24], rdx\n" " 00000059 48/ 3B 57 18 cmp rdx, QWORD PTR [rdi+24]\n" " 0000005D 49/ 8B 53 20 mov rdx, QWORD PTR [r11+32]\n" " 00000061 48/ 83 D2 00 adc rdx, 0\n" " 00000065 48/ 03 57 20 add rdx, QWORD PTR [rdi+32]\n" " 00000069 48/ 89 51 20 mov QWORD PTR [rcx+32], rdx\n" " 0000006D 48/ 3B 57 20 cmp rdx, QWORD PTR [rdi+32]\n" " 00000071 49/ 8B 53 28 mov rdx, QWORD PTR [r11+40]\n" " 00000075 48/ 83 D2 00 adc rdx, 0\n" " 00000079 48/ 03 57 28 add rdx, QWORD PTR [rdi+40]\n" " 0000007D 48/ 89 51 28 mov QWORD PTR [rcx+40], rdx\n" " 00000081 48/ 3B 57 28 cmp rdx, QWORD PTR [rdi+40]\n" " 00000085 49/ 8B 53 30 mov rdx, QWORD PTR [r11+48]\n" " 00000089 48/ 83 D2 00 adc rdx, 0\n" " 0000008D 48/ 03 57 30 add rdx, QWORD PTR [rdi+48]\n" " 00000091 48/ 89 51 30 mov QWORD PTR [rcx+48], rdx\n" " 00000095 48/ 3B 57 30 cmp rdx, QWORD PTR [rdi+48]\n" " 00000099 49/ 8B 53 38 mov rdx, QWORD PTR [r11+56]\n" " 0000009D 48/ 83 D2 00 adc rdx, 0\n" " 000000A1 33 C0 xor eax, eax\n" " 000000A3 48/ 03 57 38 add rdx, QWORD PTR [rdi+56]\n" " 000000A7 48/ 89 51 38 mov QWORD PTR [rcx+56], rdx\n" " 000000AB 48/ 3B 57 38 cmp rdx, QWORD PTR [rdi+56]\n" " 000000AF 48/ 8B 7C 24 mov rdi, QWORD PTR [rsp+16]\n" " 10\n" " 000000B4 0F 92 C0 setb al\n" " 000000B7 C3 ret 0\n" " 000000B8 ?Add@@YAHQEA_K00@Z ENDP ; Add\n" " 000000B8 _TEXT ENDS\n"; int full_size_add_listing = 0x000000B8; #define MAX_USI 100 int usi_pos[MAX_USI]; int usi_len[MAX_USI]; int kol_usi; void sbrivaem_usi(void) { char *p; int i, j; for( kol_usi=0, p=add_listing;;) //   { // cmp p = strstr(p, "cmp"); if (p==NULL) break; for(;;p--) //   2  { if (p[0]==' ' && p[1]==' ') break; } p-=2; //   sscanf(p, "%x", &(usi_pos[kol_usi])); p+=4; for(i=0;;i++) { if (p[0]<0x20) break; p+=2; if (p[0]=='/') p++; if (p[0]==' ') p++; } usi_len[kol_usi]=i; kol_usi++; if (kol_usi>=MAX_USI) { printf("too much"); exit(0); } p = strstr(p, "cmp"); //   cmp p++; // } //     for( i=kol_usi-1; i>=0; --i) { udalit_usi(usi_pos[i], usi_len[i], full_size_add_listing); full_size_add_listing -= usi_len[i]; } } int main(void) { LARGE_INTEGER lFrequency, lStart, lEnd; double dfTime1; int i, j, k, usi; BN_WORD a[8], b[8], c[8], Carry; // ,   inline    Add   main int (*add)(BN_WORD c[8], BN_WORD a[8], BN_WORD b[8]) = Add; for( i=0; i<8; i++) { a[i] = b[i] = 0x8000000000000000; } for( usi=0; usi<=1; ++usi) { QueryPerformanceFrequency(&lFrequency); QueryPerformanceCounter(&lStart); for( i=0; i<1000; ++i) { for( j=0; j<1000000; ++j) { Carry = add(c, a, b); } for( k=0; k<8; ++k) { if (Carry!=1 || c[k]!=(k!=0)) { printf("Something wrong\n"); return 1; } } } QueryPerformanceCounter(&lEnd); dfTime1 = (double)(lEnd.QuadPart - lStart.QuadPart) / (double)lFrequency.QuadPart; if (usi==0) { //    printf("Time = %g sec\n", dfTime1); //     sbrivaem_usi(); } else { //    printf("Time(without cmp) = %g sec\n", dfTime1); } } return 0; }