内存寻址在汇编中非常重要,主要有一下几种:
1.基于寄存器寻址:
2.基于寄存器+偏置
3.基于寄存器+索引寄存器;
4.基于寄存器+scale*索引寄存器;
代码:
#include <stdio.h> #include <tchar.h> extern "C" int NumFibVals_; extern "C" int MemoryAddressing_(int i, int *v1, int *v2, int *v3, int *v4); int _tmain(int argc, _TCHAR* argv[]) { for (int i = -1; i < NumFibVals_ + 1; ++i) { int v1 = -1, v2 = -1, v3 = -1, v4 = -1; int rc = MemoryAddressing_(i, &v1, &v2, &v3, &v4); printf("i:%2d rc:%2d-", i, rc); printf("v1:%5d v2:%5d v3:%5d v4:%5d ", v1, v2, v3, v4); } return 0; }
.model flat,c ; Simple lookup table (.const section data is read only) .const FibVals dword 0,1,1,2,3,5,8,13 dword 21,34,55,89,144,233,377,610 NumFibVals_ dword ($-FibVals)/sizeof dword public NumFibVals_ ; extern "C" int MemoryAddressing_(int i, int* v1, int* v2, int* v3, int*v4); ; ; Description: This function demonstrates various addressing ; modes that can be used to access operands in ; memory. ; ; Returns: 0 = error (invalid table index) ; 1 = success .code MemoryAddressing_ proc push ebp mov ebp,esp push ebx push esi push edi ;Make sure 'i' is valid xor eax,eax mov ecx,[ebp+8] ;ecx=i cmp ecx, 0 jl InvalidIndex ;jump if i<0 cmp ecx,[NumFibVals_] jge InvalidIndex ;jump if i>=NumFibVals_ ;Example #1-base register mov ebx,offset FibVals ;ebx=FibVals mov esi,[ebp+8] ;esi=i shl esi,2 ;esi=i*4 add ebx,esi ;ebx=FibVals+i*4 mov eax,[ebx] ;Load table value mov edi,[ebp+12] mov [edi],eax ;Save to 'v1' ;Example #2-base register+displacement ;esi is used as the base register mov esi,[ebp+8] ;esi=i shl esi,2 ;esi=i*4 mov eax,[esi+FibVals] ;Load table value mov edi, [ebp+16] mov [edi],eax ;Save to 'v2' ;Example #3-base register+index register mov ebx,offset FibVals ;ebx=FibVals mov esi,[ebp+8] ;esi=i shl esi,2 ;esi=i*4 mov eax,[ebx+esi] ;Load table value mov edi,[ebp+20] mov [edi],eax ;Save to 'v3' ;Example #4-base register+index register*scale factor mov ebx,offset FibVals ;ebx=FibVals mov esi,[ebp+8] ;esi=i mov eax,[ebx+esi*4] ;Load table value mov edi,[ebp+24] mov [edi],eax ;Save to 'v4' mov eax,1 ;Set return code InvalidIndex: pop edi pop esi pop ebx pop ebp ret MemoryAddressing_ endp end
运行结果: