Hacking Microsoft BASIC
Added 2024-09-30 21:08:46 +0000 UTCNew video! In this one, I modify the Microsoft BASIC code that's running on the 6502 computer to add some new instructions. Specifically, I add instructions for printing to and manipulating the LCD screen that's already part of the computer.
As always, thanks for your support and let me know if anything is unclear or if there are any other issues you see before I release this publicly.
Thanks again!
-Ben
Comments
Yes! SPI load & save, followed by interfacing to the world's worst video card!
George M1GEO
2024-10-30 23:04:33 +0000 UTCOfcourse, now the breadboard computer works with WozMon and MsBasic and lcd write commands are implemented, what else can be still be done? If I may suggest implementing a SPI interface connecting to a SD-card? And after that ofcourse adding a LOAD and SAVE command to Basic.
Remco van Zuijlen
2024-10-07 15:21:24 +0000 UTCSo, do you want to build a bootstrap to directly get into basic (without the parameters) and then have a CALL command that dumps out to WozMon?
George Harris
2024-10-07 11:17:07 +0000 UTCMy hope was definitely to get BASIC running on it from the beginning, but I didn't exactly have the entire path mapped out of how to get there. That was a very distant goal at the time. The plan at the beginning was really just that I wanted to cover a few things like the LCD or keyboard that weren't practical on the SAP 8-bit CPU. I figured the 6502 would be a better platform for those videos.
Ben Eater
2024-10-05 15:16:42 +0000 UTC@Tim Tom - I have not yet watched this episode, but I was just thinking about this same thing. I can imagine Ben thinking several months ago, "Gee, I'd love to kill a Wompus. But, an emulator is just wrong, and I don't want to fix old faulty hardware. So, what could I do. Hmmm...."
Jack McKinney
2024-10-04 16:14:58 +0000 UTCIt’s amazing looking from this episode back to where it all started. I’ve always been curious how much of it was planned/mapped out when it started. Did you know you’d eventually be running wozmon/basic on the thing when you were building a clock from 555 timers?
Tim Tom
2024-10-01 12:34:15 +0000 UTCUsing character codes to clear the screen and move the cursor would also be an interesting experiment.
Timo Haanpää
2024-10-01 08:46:39 +0000 UTCYep, Mikol's example shows how easy it is!
Ben Eater
2024-10-01 00:42:40 +0000 UTCThanks, Ben. This is a fantastic episode :)
Alistair Campbell
2024-10-01 00:00:49 +0000 UTCUnless I missing something (ver possible) this works for me: in lcd.s: LCDCLEAR: lda #%00000001 ; clear display jsr lcd_instruction rts and in token.s: .ifdef EATER keyword_rts "LCDCMD", LCDCMD keyword_rts "LCDPRINT", LCDPRINT keyword_rts "LCDCLEAR", LCDCLEAR .endif Seems to working well.
Mikol Ryon
2024-09-30 23:49:02 +0000 UTCThis is awesome, Ben! One of my favourite videos of yours!
George M1GEO
2024-09-30 23:31:46 +0000 UTCNice! I love how easy it is to add commands. I would have loved to be able to do this when I learned Assembly way back in collage (early 90s). For the next video and because clearing the screen is such a common thing to do, maybe also add an LCDCLS command.
ProgrammerDor
2024-09-30 21:53:45 +0000 UTCWoohoo!!!! This is what I've been waiting for! A thousand thanks.
Mikol Ryon
2024-09-30 21:37:42 +0000 UTC
