这是一个作业问题，我已经完成了所有的编码，但我在将汇编与C++链接时遇到了问题。我的操作系统是Windows Visual Studio 2010，我将主文件放在源文件中，将汇编文件放在资源文件中。当我尝试编译时，出现了链接错误。
1>------ Build started: Project: clearArray, Configuration: Debug Win32 ------
1>clearArray.cpp
1>clearArray.obj : error LNK2019: unresolved external symbol _clearPointerOp referenced in function _main
1>clearArray.obj : error LNK2019: unresolved external symbol _clearIndexOp referenced in function _main
1>C:\Users\Joe Chen\documents\visual studio 2010\Projects\clearArray\Debug\clearArray.exe : fatal error LNK1120: 2 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
这个作业的目标是使用索引方法和指针方法清除数组，然后优化生成的汇编代码。
请帮忙！！！
以下是我的代码： main.cpp
// clear array using unoptimized code with index and pointers
#include<iostream>
#include<fstream>
#include"timer.h"
using namespace std;
extern "C" {void clearIndexOp(int A[], int size);}
extern "C" {void clearPointerOp(int *A, int size);}
const int size = 100000;
int A[size] = {0};
void clearIndex(int A[], int size)
{
for(int i=0; i<size; i++)
A[i]=0;
}
void clearPointer(int *A, int size)
{
int *p;
for(p=&A[0]; p<&A[size]; p++)
*p=0;
}
int main()
{
double timeIndex = 0;
double timeIndexOp = 0;
double timePointer = 0;
double timePointerOp = 0;
StopWatch time;
ofstream myfile;
myfile.open("results.txt");
for(int n=2000; n<1000000; n=n*2)
{
// put values into the array
for(int i=0; i<size; i++)
A[i]=i+rand()%10+1;
time.startTimer();
clearIndex(A, size);
time.stopTimer();
timeIndex = time.getElapsedTime();
// put values into the array
for(int i=0; i<size; i++)
A[i]=i+rand()%10+1;
time.startTimer();
clearPointer(A, size);
time.stopTimer();
timePointer = time.getElapsedTime();
// put values into the array
for(int i=0; i<size; i++)
A[i]=i+rand()%10+1;
time.startTimer();
clearIndexOp(A, size);
time.stopTimer();
timeIndexOp = time.getElapsedTime();
// put values into the array
for(int i=0; i<size; i++)
A[i]=i+rand()%10+1;
time.startTimer();
clearPointerOp(A, size);
time.stopTimer();
timePointerOp = time.getElapsedTime();
myfile << "n is now: " << n << "\n";
myfile << "timeIndex is: " << timeIndex << "\n";
myfile << "timePointer is: " << timePointer << "\n";
myfile << "timeIndexOp is: " << timeIndexOp << "\n";
myfile << "timePointerOp is: " << timePointerOp << "\n";
}
myfile.close();
}
clearIndexOp.asm
.386
.model flat
.stack
.code
global _clearIndexOp proc
_i$ = -8 ; size = 4
_A$ = 8 ; size = 4
_size$ = 12 ; size = 4
; {
push ebp
mov ebp, esp
sub esp, 204 ; 000000ccH
push ebx
push esi
push edi
lea edi, DWORD PTR [ebp-204]
mov ecx, 51 ; 00000033H
mov eax, -858993460 ; ccccccccH
rep stosd
; for(int i=0; i<size; i++)
; initialize the variables
mov eax, 0 ; init i=0 to eax
mov ebx, DWORD PTR _size$[ebp] ; size stored in ebx for faster access than memory
mov ecx, DWORD PTR _A$[ebp] ; get base addr of array
jmp SHORT $LN3@clearIndex ; jump into the loop
$LN2@clearIndex:
add eax, 1 ; increase eax since eax=i
$LN3@clearIndex:
cmp eax, ebx ; check that i < size
jge SHORT $LN4@clearIndex ; exits if i >= size
; A[i]=0;
mov DWORD PTR [ecx+eax*4], 0 ; A[i]=0
jmp SHORT $LN2@clearIndex ; go back to loop body
; after removing useless/repetitive codes
; we shrunk this code from 10 instructions to only 5 instructions
$LN4@clearIndex:
; }
pop edi
pop esi
pop ebx
mov esp, ebp
pop ebp
ret 0
_clearIndexOp ENDP
clearPointerOp.asm
.386
.model flat
.stack
.code
global _clearPointerOp proc
_p$ = -8 ; size = 4
_A$ = 8 ; size = 4
_size$ = 12 ; size = 4
; {
push ebp
mov ebp, esp
sub esp, 204 ; 000000ccH
push ebx
push esi
push edi
lea edi, DWORD PTR [ebp-204]
mov ecx, 51 ; 00000033H
mov eax, -858993460 ; ccccccccH
rep stosd
; int *p;
; for(p=&A[0]; p<&A[size]; p
; initialize the variables
mov eax, DWORD PTR _A$[ebp] ; base addr of the array
mov DWORD PTR _p$[ebp], eax ; init p = A[0]
mov ebx, DWORD PTR _p$[ebp] ; move p to ebx
mov ecx, DWORD PTR _size$[ebp] ; size stored in ecx for faster access from register
lea edx, DWORD PTR [ecx+eax*4] ; last index of array, A[size-1]
jmp SHORT $LN3@clearPoint ; jump into loop
$LN2@clearPoint:
add eax, 4 ; since it is pointer we increase eax by 4 to move to next element
$LN3@clearPoint:
cmp ebx, edx ; check that p < size
jae SHORT $LN4@clearPoint ; exit if p >= size
; *p=0;
mov DWORD PTR [ebx], 0
jmp SHORT $LN2@clearPoint
; after removing useless/repetitive codes
; we shrunk this code from 11 instructions to only 5 instructions
$LN4@clearPoint:
; }
pop edi
pop esi
pop ebx
mov esp, ebp
pop ebp
ret 0
_clearPointerOp ENDP