run c app in asm

[Yarin]

How would I execute a C/C++ written program from an asm program with pure DOS?

[CornedBee]

DOS???

Also, this is an assembly or DOS API question, not C++. Moved.

Meh. Even from assembly, I think I'd link against a CRT and use exec(). But Interrupt 21 function 5b looks promising.

[MacGyver]

Meh. Even from assembly, I think I'd link against a CRT and use exec().

Using C library functions is definitely the way to go in assembly if it's an option.

I would argue that DOS should be dead now, though.

[Yarin]

Okay, I was already sort of on that track. Here is the asm I have so far

jmp start

Filename db 'CPROGRAM.EXE', 0

getkey:
   mov ah, 0
   int 016h
   ret

start:
   mov ah, 40h
   mov al, 0
   mov dx, Filename
   mov ds, dx
   mov bx, 0
   mov es, bx
   int 21h
   call getkey
   ret

It took me a while to get together. cprogram.exe was compiled with DJGPP; here's it's code

#include <stdio.h>
 
int main(void)
{
   printf("Starting...\n\n");
   printf("Good news; This is a real live running C program.\n");
   printf("\nEnding...\n");
   return 0;
}

But the asm program displays this:

♀☻
☻█☻─      ♀☻ï♣♀☻♫♀♀☻¶♀♀☻▼♀♀☻¡♠♀☻¡♠♀☻ñ≡ ≡7♣♀☻N+ └r►º |►º ▐☺¶♦K☺¶♦V☺¶♦å►º É►º Ü►º
╕►º T☻p ≥♦ï╙╕►º ╕►º ╕►º @☺¶♦P  ╖♀Ω«►º
 ≡╕►º ─#☻╨╕►º ╕►º ╕►º ╕►º ╕►º ╕►º ╕►º ╕►º ╕►º ╕►º ╕►º ╕►º è♦♀☻ ♥♀☻v   ♀☻a/ └╢
 ≡╢
 ≡╢
 ≡╢
 ≡╢

As you can see I have a major glitch error.

Help me out a little here?

[CornedBee]

My reference tells me that 40h is WriteFile.

[Yarin]

But I am interrupting 21h am I not?

Do you know where I could get a copy of this reference? (Assuming you have a list of interrupts)

[CornedBee]

The problem is that the reference is in German.

But perhaps Ralf Brown's list would be a good reference. http://www.ctyme.com/rbrown.htm
Look for int 21h, and there you can look up the function you want. 40h, as I said, is Write File.

This page looks interesting, too: http://www.ctyme.com/intr/cat-010.htm

[abachler]

I would argue that DOS should be dead now, though.

mmm, not quite yet Im afraid, its still used in some industrial machines. Stability , runs on the 80188 uC/uP, entire OS+Environment fits in the L2 cache on newer processors. Just some of its few benefits.