Day 17 started with me looking into the heart of the machine with the jump instructions JP and JR. JP takes a two-byte address and jumps directly to that address. JR is the equivalent, but instead of taking an address it takes a (signed ) byte to jump relative to the …

Day 16 and I'm playing around with the stack on the ZX Spectrum (using MONS4). The stack is a really neat concept and I can't imagine modern computing without it. blame Alan Turing for the concept of a stack (though instead of push and pop he used the terms bury …

This piece shows why I still regularly blog, and why I went through the pain of changing over from Wordpress to Pelican. We need to save the independent places of creativity and thought.

The Web We Have to Save

Started on chapter 5 which covers the stack and the stack register. This feels like old hat now that I've played with computers for a while now but I'm sure that an earlier version of me would have been a little confused on how the stack worked. But it's pretty …

Tonight I completed chapter 4 of the Mastering Machine Code on your Spectrum. This section dealt with "POKE" commands in machine code, and introduced the LDI, LDD, and LDIR op-codes. LDIR is especially interesting as it uses BC explicitly as a counter for memory moves. It's a pretty primitive way …