Author Archives: paul

It dawned on me yesterday this whole silliness would be a lot easier if I had a debugger.  And of course I’ve made everything more complicated by insisting on using Z80 mnemonics, because the stock debugger, DDT, only speaks 8080.  … Continue reading →

Yesterday we got a simple routine working that set a selected bit on a word using a few registers. Lets see if we can select that bit using the command line. output a message prompting the user for the bit … Continue reading →

Time to fail for another hour at assembly language…  Yesterday I think the routines for writing to the console were tripping me up, so I’m going to start a new file with none of that and just write to port … Continue reading →

Lost a day yesterday due to the move and date night with the Wife.  I’m doin’ my best here… So my understanding of how relative & indexed jumps work on the 8080 & Z80 was just flawed.  There’s no variable … Continue reading →

lets make a subroutine that can set or clear a selected bit in the CTC control register.  To call the routine, we need to tell it: – The CTC channel – Which bit we’re adjusting – If we’re setting or … Continue reading →

So, for whatever reason, I can’t use include files, which means I just have to have everything in one large assembly file.  I guess that’s not the end of the world. Lets start by trying to set up the timer … Continue reading →

Before I make a simple program to test the CTC, I’d like to learn how the assembler deals with multiple files.  The simplest way is to use the INCLUDE pseudo-op: INCLUDE  <FILENAME.EXT> will simply open the .ext file and insert … Continue reading →

Yesterday proved I need to take a step back. So let me actually take my time and write a proper ‘Hello World’ program. I’m going to do this in VS Code, since it’s just nicer to type on a 21st … Continue reading →

I lost 2 days – one to being knocked out by the booster, and the other from apathy, laziness, and distractions.  That’s so fucking like me… OK, back at it. I doubt I’m going to get a light blinking today, … Continue reading →

I got my booster today and it’s Friday, so I’m a little drained, but at least want to try to do something.  So I’ll do a little CP/M housekeeping. The CF Card is IDE0.  ROMWBW introduces partitioning that it calls … Continue reading →