两个大整数相乘的汇编语言实现

.386 .model flat,stdcall option casemap:none includelib msvcrt.lib include msvcrt.inc printf PROTO C :dword, :VARARG scanf PROTO C :ptr sbyte,:vararg .data szFmt1 byte '%d',0 szFmt2 byte 'Please input the lenth of NumA',0ah,0 szFmt3 byte 'Please input NumA',0ah,0 szFmt4 byte 'Please input the lenth of NumB',0ah,0 szFmt5 byte 'Please input NumB',0ah,0 szFmt byte '%d',0 NumA byte '5552411648486158345165841513184515313515465435131548543413135485468543513513543541513515366661651295' NumB byte '3331513184515313515465435131548543413135485468543513511513184515313515465435131548543413188889878396' A byte 100 dup(?) B byte 100 dup(?) Result dd 300 dup(?) LenA dd 100 LenB dd 100 Max dd 300 ten dd 10 .code start proc mov al,'0' mov ecx,LenA mov ebx,0 e1: sub NumA[ebx],al ;第一个操作数 - 0 mov dl,NumA[ebx] mov A[ecx-1],dl ;倒序存放到A inc ebx loop e1 mov ebx,0 mov ecx,LenB e2: sub NumB[ebx],al ;第二个操作数 - 0 mov dl,NumB[ebx] mov B[ecx-1],dl ;倒序存放到B inc ebx loop e2 mov ecx,0 xor eax,eax xor ebx,ebx e3: mov edx,0 e4: mov al,A[ecx] ;相乘 mov bl,B[edx] imul eax,ebx ;两个个位数相乘不会大于127 mov edi,ecx add edi,edx add Result[edi*4],eax inc edx cmp edx,LenB jl e4 inc ecx cmp ecx,LenA jl e3 mov ecx,Max ;将进位加到前一位上 mov ebx,10 mov edi,0 e5: cmp Result[edi*4],ebx ;一定记得dd 乘4 ！！！！ jl e6 mov eax,Result[edi*4] xor edx,edx idiv ebx add Result[edi*4+4],eax mov Result[edi*4],edx e6: inc edi loop e5 mov ecx,Max e7: dec ecx ;除去前导0 cmp Result[ecx*4],0 jz e7 e8: push ecx invoke printf,offset szFmt,Result[ecx*4] ;倒序输出 pop ecx dec ecx cmp ecx,0 jnl e8 ret start endp end start