SVC_ERROREXIT

Terminate MVM with error message (far pointer to ASCIIZ message on stack)

• Stack (top) = far pointer (segment:offset) to an ASCIIZ message string

This function does not return. The MVM is terminated and control passes to the host operating system.

• The message must be a null‑terminated ASCII string.
• The far pointer must be pushed onto the stack (segment first, then offset) before issuing the HLT instruction.
• Because the call never returns, no registers are preserved and the carry flag is undefined.

include macrolib.inc
 
    push ds
    push offset msg
    @SvcErrorExit
 
msg db "Fatal error",0

#include <svc.h>
 
void main(void) {
    SvcErrorExit("Fatal error");
}

The underlying pragma is defined as:

extern void SvcErrorExit(const char far *msg);
#pragma aux SvcErrorExit = \
    "hlt"           \
    "db  1"         \
    "db  NOT 1"     \
    parm caller [] [msg] \
    modify [ax bx cx dx];

• SVC_EXIT – terminate without a message
• INT 21h AH=4Ch – DOS terminate with return code