Question

I want to use IM 1 interrupt mode on Z80.

In Interrupt mode 1 processor jumps to 38h address in memory(am I right?) and then continues interrupt. How can I specify this in my code?
I have read about:

defs [,] ds [,] This pseudo
instruction inserts a block of bytes into the code segment

I need some sample source code.

Kind Regards

Rafał R.

Answer 1

First off, I don’t have a Z80 in front of me.

Referencing: Z80asm directives

Use org to ‘manually’ locate a ‘function’ at a specified address.
So, to write an IM1 handler:

org 0x38
; IM1 handler 
ld a, 100 ; ... whatever
ret

Also, I’m not sure of your normal starting address is, but the original Z80s started at location 0. If this is the case you should JMP past the 0x38 handler very early in your code. (You only have 56 bytes to play with)

Happy Coding!