C / C++ / MFC

OUT parameters in inline asm

29-Mar-11 10:48

The information you need is passed back with the notification message as described here[^]. When investigating issues like this you should always go to the MSDN reference documentation first.

d@nish[^] has the answer.

csrss29-Mar-11 3:25

csrss

29-Mar-11 3:25

Hey guys. Lets say, i have such function, like:

void Stuff(int A, int *B);

So as you can see, B is OUT parameter. The question is, how would you call it from inline assembly code?
Something like this:

void Some(int A){ //do something with a }
__asm
{
    push 1
    call dword ptr Some
}

// or this

int Some(int A, int B){ // do something with variables and return some integer }
__asm
{
    push 2
    push 5
    call dword ptr Some
    // now the function result is in eax, so we can grab it and store in some variable, and do something with it later
}

but how to do it with this: void Stuff(int A, int *B) ? How to get B?
Thanks

011011010110000101100011011010000110100101101110
0110010101110011

Re: OUT parameters in inline asm [SOLVED]

csrss29-Mar-11 4:17

csrss

29-Mar-11 4:17

Ok, solved it myself.

#include <windows.h>
#include <iostream>

using namespace std;

void Func(int A, int *B, int *C)
{
	*B += ++A;
	*C *= *B + 1;
}

int main()
{
	int B = 3;
	int C = 6;
	__asm
	{
		lea ecx, C
		push ecx
		xor ecx, ecx
		lea ecx, B
		push ecx
		push 3
		call dword ptr Func
		add esp, 12
	}
	cout << B << " : " << C << endl;
}

011011010110000101100011011010000110100101101110
0110010101110011

Bit extraction from byte

sathishrdh29-Mar-11 2:22

sathishrdh

29-Mar-11 2:22

How to extract two bits simultaneously from a byte ?

Niklas L29-Mar-11 2:27

Niklas L

29-Mar-11 2:27

Use bitwise AND operator.

C++

unsigned char b = 0xFF;

// Get two LSB
unsigned char result = (b & 0x03);

(0x03 has the lowest two bits set.)

home

Albert Holguin29-Mar-11 3:50

Albert Holguin

29-Mar-11 3:50

Don't think it has to be unsigned, but this works great and is commonly used.

Peter_in_278029-Mar-11 11:43

Peter_in_2780

29-Mar-11 11:43

unsigned can make a big difference if the top bit is one of those involved.

Software rusts. Simon Stephenson, ca 1994.

Albert Holguin29-Mar-11 12:51

Albert Holguin

29-Mar-11 12:51

not really, not if you're dealing with bit level operations... as long as you're not using the data to do arithmetic, but this type of logic is usually used for dealing with APIs and hardware type of operations.

French localization using Single-byte character set (SBCS)

Stefan_Lang30-Mar-11 1:53

Stefan_Lang

30-Mar-11 1:53

As mentioned above, use '&' to test for a bit pattern. I've illustrated that in the inline function extract below.

If you don't have the actual values of the bits to test for though, you may need to combine the variables that contain the test bits. In that case use the bitwise or operator '|'. I've illustrated that in the inline function test2Flags below.

You can easily combine more than 2 flags to test for by combining several of them with '|'. See the last call to extract below.

typedef unsigned char byte;
const byte indicator1 = 0x01;
const byte indicator2 = 0x02;
const byte indicator3 = 0x04;
const byte indicator4 = 0x08;
const byte indicator5 = 0x10;
const byte indicator6 = 0x20;
const byte indicator7 = 0x40;
const byte indicator8 = 0x80;

inline byte extract(byte indicators, byte mask) {
    return indicators & mask;
}
inline test2Flags(byte indicators, byte flag1, byte flag2) {
    return extract(indicators, flag1 | flag2);
}
int main() {
    byte myIndicator = 0x34;
    byte testMyIndicators3and5 = test2Flags(myIndicator, indicator2, indicator5); // result is 0x10
    byte testSeveralFlags = extract(myIndicators, indicator2 | indicator3 | indicator4); // = 0x04
    return 0;
}

Of course, you don't need to define any function for that, I just did this to enhance readability and focus on the relevant syntax.

Selvam R28-Mar-11 23:27

Selvam R

28-Mar-11 23:27

Hi,

We are going to support our application for French localization (iso-8859-1 Windows-1252). The application developed using C++ and C# technologies. As per my understanding, if we support Unicode or MBCS (Multi-byte character set), we won’t get any data loss. Can we use normal string function for handle French characters or _MBCS requires for handle French characters?
Example:
Can we

if( *sz1 == 'A' )

for Character Comparison or

if( !_mbccmp( sz1, sz2) )

Thanks and Regards,
Selvam,
http://www15.brinkster.com/selvamselvam/

Re: French localization using Single-byte character set (SBCS)

Richard MacCutchan28-Mar-11 23:59

Re: French localization using Single-byte character set (SBCS)

28-Mar-11 23:59

It looks like you plucked your question from here[^] where it explains the issue. It does not matter what character encoding you use if it's the same everywhere, just use the correct functions for your string manipulation, and ensure all constants are held in the correct encoding.

d@nish[^] has the answer.

Selvam R29-Mar-11 0:25

Selvam R

29-Mar-11 0:25

Hi Richard,

Thanks for your help. so, I can use ASCII functions(string manipulations, Windows API functions , etc) for my French application. Is it?

Thanks and Regards,
Selvam,
http://www15.brinkster.com/selvamselvam/

Re: French localization using Single-byte character set (SBCS)

Richard MacCutchan29-Mar-11 3:09

Re: French localization using Single-byte character set (SBCS)

29-Mar-11 3:09

R.selvam wrote:
so, I can use ASCII functions(string manipulations, Windows API functions , etc) for my French application. Is it?

Yes, assuming all your text is in ASCII.

d@nish[^] has the answer.

Selvam R29-Mar-11 18:48

Selvam R

29-Mar-11 18:48

Thank you.

Thanks and Regards,
Selvam,
http://www15.brinkster.com/selvamselvam/

How to revert SetCheckBox style ? [modified]

_Flaviu28-Mar-11 21:30

_Flaviu

28-Mar-11 21:30

On a tree control , with

m_Tree.ModifyStyle(TVS_CHECKBOXES,0);
m_Tree.ModifyStyle(0,TVS_CHECKBOXES);

I put checkbox style , but how can I turn off this style if they already exist ?
I try this , but it is a stupid :

m_Tree.ModifyStyle(~TVS_CHECKBOXES,0);
m_Tree.ModifyStyle(0,~TVS_CHECKBOXES);

modified on Tuesday, March 29, 2011 3:58 AM

Richard MacCutchan28-Mar-11 22:32

28-Mar-11 22:32

Flaviu 2 wrote:
m_Tree.ModifyStyle(TVS_CHECKBOXES,0);

Use GetStyle()[^] to check what styles are already set, and modify as appropriate.

d@nish[^] has the answer.

_Flaviu29-Mar-11 5:03

_Flaviu

29-Mar-11 5:03

And how to modify them if I want to set back to 0 ?

Richard MacCutchan29-Mar-11 5:36

29-Mar-11 5:36

Check if that style bit is set in the return from GetStyle() and if so you can remove it; if not set then no action.

d@nish[^] has the answer.