Cancel RTS instruction Assembler

[Grevle]

How to cancel a RTS instruction in assembler ?.  In a JSR loop when you want to break out of the loop with a jmp and need to cancel the jsr stored return adress , Just do a simple PLA ? or CLC ?

 

 

[flashjazzcat]

Two PLAs in a row will remove the return address from the stack.

[Grevle]

Thanks, i should have know that by now but i been away from programming for quite some time..

[ivop]

This feature can also be used as tail call optimization. If your subroutine ends with:

	jsr some_routine
	rts

you can optimize it to:

	jmp some_routine

 

That's valid for every point where your subroutine ends. So:

	beq zero
	bmi minus

	jsr do_plus
	rts

minus
	jsr do_minus
	rts

zero
	jsr do_zero
	rts

equals:

	beq zero
	bmi minus

	jmp do_plus

minus
	jmp do_minus

zero
	jmp do_zero

 

Edited July 11, 2020 by ivop