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Troy Martin wrote:Hmm, try adding push es before xor ax,ax and pop es after sti (and you don't really need sti in there.)

Troy Martin wrote:EDIT: Why does interrupt 0 return?

Troy Martin wrote:And why don't you setup printf to make \n the same as \r\n?

kop99 wrote:Risc, if you have any bochs logs, then post that.
And do you load idtr?
So, post that code.

asm mov dx, int0
asm mov WORD [es:0x0], dx      /* Add the Interrupt procedure location to the IVT */

mov WORD [es:0x0], INT_0      /* Add the Interrupt procedure location to the IVT */

Risc wrote: EDIT: I strongly believe that the following lines are a cause of the problem.

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asm mov dx, int0
asm mov WORD [es:0x0], dx      /* Add the Interrupt procedure location to the IVT */

In pure assembler (NASM) I would have written:

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mov WORD [es:0x0], INT_0      /* Add the Interrupt procedure location to the IVT */

I don't know how to do that in TASM since it expects the second argument to be a register (note that int0 and INT_0 are two different things)...

mov word ptr es:[0], offset INT_0

push cs
push offset INT_0
pop word ptr es:[0]
pop word ptr es:[2]

Risc wrote:asm mov dx, int0

I would appreciate any input.

Risc wrote:It doesn't return in a normal fashion.

ru2aqare wrote:

Risc wrote: EDIT: I strongly believe that the following lines are a cause of the problem.

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asm mov dx, int0
asm mov WORD [es:0x0], dx      /* Add the Interrupt procedure location to the IVT */

In pure assembler (NASM) I would have written:

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mov WORD [es:0x0], INT_0      /* Add the Interrupt procedure location to the IVT */

I don't know how to do that in TASM since it expects the second argument to be a register (note that int0 and INT_0 are two different things)...

Try

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mov word ptr es:[0], offset INT_0

or even

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push cs
push offset INT_0
pop word ptr es:[0]
pop word ptr es:[2]

TASM and compatibles have the offset keyword (which NASM lacks unfortunately).

mov dx,word ptr [int0]
mov WORD [es:0x0], dx

Combuster wrote:use getvect() and setvect(), turbo C has them for a reason.

mathematician wrote:Assuming that they don't call MS-DOS functions 35h (get vector) and 25h (set vector).

void printc(char c)
{
	asm push ax
	/* Print a character on screen */
	asm mov al, c
	asm mov ah, 0x0e
	asm int 0x10
	asm pop ax
}

/* Prints a string */
void printf(char* str)
{
	int i = 0;
	while(str[i] != '\0')
		printc(str[i++]);
}

void interrupt INT_0()
{
	/* putc('a'); WORKS */
	printf("Hello world\0"); /* No cigar... */
	asm hlt
}

Risc wrote:

mathematician wrote:Assuming that they don't call MS-DOS functions 35h (get vector) and 25h (set vector).

It seems that they do unfortunately.

However, ru2aqare's code did the trick! It successfully traps to the correct function.
Now I seem to be having a stack problem or something because I can successfully do printc (print a character) but I can't printf (print a string). In Bochs it looks like printf never calls printc but sits around in an endless loop (remember, normally this works fine, it's just when calling it from the interrupt function). The interrupt function does nothing special btw.

Have a look at the code below:

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void printc(char c)
{
	asm push ax
	/* Print a character on screen */
	asm mov al, c
	asm mov ah, 0x0e
	asm int 0x10
	asm pop ax
}

/* Prints a string */
void printf(char* str)
{
	int i = 0;
	while(str[i] != '\0')
		printc(str[i++]);
}

...

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void interrupt INT_0()
{
	/* putc('a'); WORKS */
	printf("Hello world\0"); /* No cigar... */
	asm hlt
}