Kenbak-1 demo program.

[phe]

Excellent idea for a program. I'll have to try to replicate it on the 8800.

This is interesting code to read. JMD must be like a CALL. I can't figure out how the WAIT subroutine returns. Does the Kenbak have a stack? Where is the equivalent "RET" instruction?

Paul

[Geoff Harrison]

Originally Posted by phe

Does the Kenbak have a stack? Where is the equivalent "RET" instruction?
Paul

No, no stack on a Kenbak. The JMD (Jump and Mark Direct) instruction stores the value {program counter}+2 at the address in the operand, then jumps to the address {operand}+1. To return you do an unconditional JPI (Jump Indirect) using the start of the subroutine as the operand, which returns you to the instruction following the JMD. It's all pretty neat but it means you can't do recursion, of course