Mixing
MASM: iterate through 3 arrays
I have to write some code in assembly for the classes. I want to pass three arrays of char to the asm function. Then I want to make some operations on two of them and the save to the third one.
I already found one answer: passing arrays to functions in x86 asm, but it doesn't seem work for me, because I don't have any registers left to make calculations.
.model flat, stdcall
.386
.stack 4096
.data
.code
MyProc1 proc plainTab: DWORD, resultTab: DWORD, keyTab: DWORD ,len: DWORD
xor ecx, ecx
xor edx, edx
xor ebx, ebx
xor eax, eax
xor esi, esi
mov ebx, plainTab
mov edx, resultTab
mov eax, keyTab
mov ecx, len
myloop: mov bl, [ebx]
add bl, [eax]
mov [edx], bl
inc ebx
inc edx
inc eax
dec ecx
jnz myloop
ret
MyProc1 endp
end
And this is how it looks like in the c++ main:
int main() {
typedef char* (WINAPI *MYPROC1)(char*, char* ,char* ,int);
MYPROC1 MyFunc1;
HMODULE hLib;
const int n = 9;
char plainText[n] = { 'm', 'e', 's', 's', 'a', 'g', 'e', 'e', 'e' };
char key[n] = { 'k', 'e', 'y', 'k', 'e', 'y', 'k', 'e', 'y' };
char result[n] = {''};
if ((hLib = LoadLibrary(L"Asm.dll")) != NULL) {
MyFunc1 = (MYPROC1)GetProcAddress(hLib, "MyProc1");
if (MyFunc1 != NULL)
{
MyFunc1(plainText, result, key, n);
for (int i = 0; i < n; i++)
std::cout << result[i] << " ";
std::cout << std::endl;
}
FreeLibrary(hLib);
}
return 0;
}
Is there any good method to solve this problem? I just started to learn assembly.
arrays assembly masm
asked Nov 19 '18 at 20:31
MichalMichal
81
add a comment |
I have to write some code in assembly for the classes. I want to pass three arrays of char to the asm function. Then I want to make some operations on two of them and the save to the third one.
I already found one answer: passing arrays to functions in x86 asm, but it doesn't seem work for me, because I don't have any registers left to make calculations.
.model flat, stdcall
.386
.stack 4096
.data
.code
MyProc1 proc plainTab: DWORD, resultTab: DWORD, keyTab: DWORD ,len: DWORD
xor ecx, ecx
xor edx, edx
xor ebx, ebx
xor eax, eax
xor esi, esi
mov ebx, plainTab
mov edx, resultTab
mov eax, keyTab
mov ecx, len
myloop: mov bl, [ebx]
add bl, [eax]
mov [edx], bl
inc ebx
inc edx
inc eax
dec ecx
jnz myloop
ret
MyProc1 endp
end
And this is how it looks like in the c++ main:
int main() {
typedef char* (WINAPI *MYPROC1)(char*, char* ,char* ,int);
MYPROC1 MyFunc1;
HMODULE hLib;
const int n = 9;
char plainText[n] = { 'm', 'e', 's', 's', 'a', 'g', 'e', 'e', 'e' };
char key[n] = { 'k', 'e', 'y', 'k', 'e', 'y', 'k', 'e', 'y' };
char result[n] = {''};
if ((hLib = LoadLibrary(L"Asm.dll")) != NULL) {
MyFunc1 = (MYPROC1)GetProcAddress(hLib, "MyProc1");
if (MyFunc1 != NULL)
{
MyFunc1(plainText, result, key, n);
for (int i = 0; i < n; i++)
std::cout << result[i] << " ";
std::cout << std::endl;
}
FreeLibrary(hLib);
}
return 0;
}
Is there any good method to solve this problem? I just started to learn assembly.
arrays assembly masm
asked Nov 19 '18 at 20:31
MichalMichal
81
2
When you run out of registers you can use local variables. That said it's unclear what you are trying to calculate as you still haveesiandediavailable which might suffice. Also note you should make sure to adhere to calling convention by preserving certain registers.
– Jester
Nov 19 '18 at 20:43
add a comment |
I have to write some code in assembly for the classes. I want to pass three arrays of char to the asm function. Then I want to make some operations on two of them and the save to the third one.
I already found one answer: passing arrays to functions in x86 asm, but it doesn't seem work for me, because I don't have any registers left to make calculations.
.model flat, stdcall
.386
.stack 4096
.data
.code
MyProc1 proc plainTab: DWORD, resultTab: DWORD, keyTab: DWORD ,len: DWORD
xor ecx, ecx
xor edx, edx
xor ebx, ebx
xor eax, eax
xor esi, esi
mov ebx, plainTab
mov edx, resultTab
mov eax, keyTab
mov ecx, len
myloop: mov bl, [ebx]
add bl, [eax]
mov [edx], bl
inc ebx
inc edx
inc eax
dec ecx
jnz myloop
ret
MyProc1 endp
end
And this is how it looks like in the c++ main:
int main() {
typedef char* (WINAPI *MYPROC1)(char*, char* ,char* ,int);
MYPROC1 MyFunc1;
HMODULE hLib;
const int n = 9;
char plainText[n] = { 'm', 'e', 's', 's', 'a', 'g', 'e', 'e', 'e' };
char key[n] = { 'k', 'e', 'y', 'k', 'e', 'y', 'k', 'e', 'y' };
char result[n] = {''};
if ((hLib = LoadLibrary(L"Asm.dll")) != NULL) {
MyFunc1 = (MYPROC1)GetProcAddress(hLib, "MyProc1");
if (MyFunc1 != NULL)
{
MyFunc1(plainText, result, key, n);
for (int i = 0; i < n; i++)
std::cout << result[i] << " ";
std::cout << std::endl;
}
FreeLibrary(hLib);
}
return 0;
}
Is there any good method to solve this problem? I just started to learn assembly.
arrays assembly masm
asked Nov 19 '18 at 20:31
MichalMichal
81
I have to write some code in assembly for the classes. I want to pass three arrays of char to the asm function. Then I want to make some operations on two of them and the save to the third one.
I already found one answer: passing arrays to functions in x86 asm, but it doesn't seem work for me, because I don't have any registers left to make calculations.
.model flat, stdcall
.386
.stack 4096
.data
.code
MyProc1 proc plainTab: DWORD, resultTab: DWORD, keyTab: DWORD ,len: DWORD
xor ecx, ecx
xor edx, edx
xor ebx, ebx
xor eax, eax
xor esi, esi
mov ebx, plainTab
mov edx, resultTab
mov eax, keyTab
mov ecx, len
myloop: mov bl, [ebx]
add bl, [eax]
mov [edx], bl
inc ebx
inc edx
inc eax
dec ecx
jnz myloop
ret
MyProc1 endp
end
And this is how it looks like in the c++ main:
int main() {
typedef char* (WINAPI *MYPROC1)(char*, char* ,char* ,int);
MYPROC1 MyFunc1;
HMODULE hLib;
const int n = 9;
char plainText[n] = { 'm', 'e', 's', 's', 'a', 'g', 'e', 'e', 'e' };
char key[n] = { 'k', 'e', 'y', 'k', 'e', 'y', 'k', 'e', 'y' };
char result[n] = {''};
if ((hLib = LoadLibrary(L"Asm.dll")) != NULL) {
MyFunc1 = (MYPROC1)GetProcAddress(hLib, "MyProc1");
if (MyFunc1 != NULL)
{
MyFunc1(plainText, result, key, n);
for (int i = 0; i < n; i++)
std::cout << result[i] << " ";
std::cout << std::endl;
}
FreeLibrary(hLib);
}
return 0;
}
Is there any good method to solve this problem? I just started to learn assembly.
arrays assembly masm
arrays assembly masm
asked Nov 19 '18 at 20:31
MichalMichal
81
asked Nov 19 '18 at 20:31
MichalMichal
81
asked Nov 19 '18 at 20:31
MichalMichal
81
asked Nov 19 '18 at 20:31
MichalMichal
81
asked Nov 19 '18 at 20:31
MichalMichal
81
81
2
When you run out of registers you can use local variables. That said it's unclear what you are trying to calculate as you still haveesiandediavailable which might suffice. Also note you should make sure to adhere to calling convention by preserving certain registers.
– Jester
Nov 19 '18 at 20:43
add a comment |
2
When you run out of registers you can use local variables. That said it's unclear what you are trying to calculate as you still haveesiandediavailable which might suffice. Also note you should make sure to adhere to calling convention by preserving certain registers.
– Jester
Nov 19 '18 at 20:43
2
2
When you run out of registers you can use local variables. That said it's unclear what you are trying to calculate as you still have
esi and edi available which might suffice. Also note you should make sure to adhere to calling convention by preserving certain registers.– Jester
Nov 19 '18 at 20:43
When you run out of registers you can use local variables. That said it's unclear what you are trying to calculate as you still have
esi and edi available which might suffice. Also note you should make sure to adhere to calling convention by preserving certain registers.– Jester
Nov 19 '18 at 20:43
add a comment |
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2
When you run out of registers you can use local variables. That said it's unclear what you are trying to calculate as you still have
esiandediavailable which might suffice. Also note you should make sure to adhere to calling convention by preserving certain registers.– Jester
Nov 19 '18 at 20:43