libnds: Early read of X Key input and memset issue.

[Sylus101]

Running this quick program displays the text shown without the key held. Tested in no$gba (text shows twice) and on hardware (text shows once). Same occurs with KEY_Y and KEY_TOUCH.

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#include <nds.h>
#include <stdio.h>

int main(void) {

consoleDemoInit();

	while(1){
	
		scanKeys();
	
		if(keysHeld() & KEY_X)
			iprintf("This shouldn't show up");
		
		swiWaitForVBlank();
	}

	return 0;
}

EDIT - I also ran across something else, usage of memset on lines 161 and 188 of background.c are:

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memset(&bgState[layer], sizeof(BgState), 0); //line 161
//and
memset(&bgState[layer + 4], sizeof(BgState), 0); //line 188

Should be:

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memset(&bgState[layer], 0, sizeof(BgState)); //line 161
//and
memset(&bgState[layer + 4], 0, sizeof(BgState)); //line 188

[ambient_enigma]

I had a similar problem that was solved by removing the following lines:

irqInit();
irqEnable(IRQ_VBLANK);

The problem went away after that. Hopefully that will help you, even though I
don't see those lines in your code.
You can see my original post under devkitARM on the index page in the post
"X,Y buttons and Touch Screen Unresponsive in New devkitARM"

[Sylus101]

Yea, those lines aren't in there. It was posted on the main site when 1.3.1 came out that those lines would need to be removed as it's being done beforehand.

Still, it surely happens just with what I've got here... hoping someone can duplicate as well and verify.

[afireohno]

Sylus, I ran into the same problem and after a great deal of frustration and trying random solutions got something to work. I'm not sure why, and it is definitely far from an elegant solution.

Code: Select all

#include <nds.h>
#include <stdio.h>

int main() 
{		
	consoleDemoInit();	
	for (int i = 0; i <2; i++)
	{
		swiWaitForVBlank(); //wait 2 or more (tested up to 10)
	}
	
	int test = 0;
	while(1) {		
		scanKeys();		
		if(keysHeld() & KEY_X)
		{
			test = 1;
		}
		swiWaitForVBlank();
		consoleClear();		
		printf("test = %i",test);		
	}
	return 0;
}

Like I said I have no idea why, but it seems to work. Thoughts anyone?