Z80:
modify address in register: inc hl
modify data pointed by register: inc (hl)
use constant: ld a, 42
read constant address: ld a, (42)

68k:
modify address in register: addq #1, a0
modify data pointed by register: addq #1, (a0)
use constant: move #42, d0
read constant address: move 42, d0

There's a good reason why 68k created that inconsistency around immediate data and absolute addresses, but it's annoying that I keep making mistakes when moving between CPUs

#Z80 #mc68000 #RetroComputing

Z80:
modify address in register: inc hl
modify data pointed by register: inc (hl)
use constant: ld a, 42
read constant address: ld a, (42)

68k:
modify address in register: addq #1, a0
modify data pointed by register: addq #1, (a0)
use constant: move #42, d0
read constant address: move 42, d0

There's a good reason why 68k created that inconsistency around immediate data and absolute addresses, but it's annoying that I keep making mistakes when moving between CPUs

#Z80 #mc68000 #RetroComputing

I need to stop inventing new #RetroComputing projects in my head.

Otherwise, I'll soon find myself coding a racing game and a vertical shooter on the #AmstradCPC

I need to stop inventing new #RetroComputing projects in my head.

Otherwise, I'll soon find myself coding a racing game and a vertical shooter on the #AmstradCPC

My system 7 project is continuing at a good clip, ps/2 keyboard input, sb16 emulation and started converting the pascal and assembly source for macpaint from Bill Atkinson to C also for inclusion #RetroComputing #macintosh #OpenSource https://github.com/Kelsidavis/System7

My system 7 project is continuing at a good clip, ps/2 keyboard input, sb16 emulation and started converting the pascal and assembly source for macpaint from Bill Atkinson to C also for inclusion #RetroComputing #macintosh #OpenSource https://github.com/Kelsidavis/System7

Alright I have designed a little ISA: https://gist.github.com/mortie/d678c4663fe705219e5dfe90e0bbdc3d. It's somewhat 6502-inspiret, but I think it's cute.

Not done yet, but I think it's a decent starting point. Next step: writing a VM and an assembler...

#computerScience #cpu #cpudesign #assembly #retrocomputing

🚀 Learn 6502 v0.4.0 is here! 🎮💜

The virtual game-console playground for learning classic 6502 assembly just got a colourful upgrade:

* New theme system with vibrant handheld-inspired palettes

* Adaptive layouts that look great on desktops, laptops, and tablets

Grab the fresh build on Flathub 👉 https://flathub.org/apps/eu.jumplink.Learn6502

#GNOME #Flathub #Learn6502 #RetroComputing #FOSS #GameDev #Assembler #6502

🚀 Learn 6502 v0.4.0 is here! 🎮💜

The virtual game-console playground for learning classic 6502 assembly just got a colourful upgrade:

* New theme system with vibrant handheld-inspired palettes

* Adaptive layouts that look great on desktops, laptops, and tablets

Grab the fresh build on Flathub 👉 https://flathub.org/apps/eu.jumplink.Learn6502

#GNOME #Flathub #Learn6502 #RetroComputing #FOSS #GameDev #Assembler #6502

History of the GEM desktop environment

The 1980s saw a flurry of graphical user interfaces pop up, almost all of them in some way made by people who got to see the work done by Xerox. Today's topic is no exception - GEM was developed by Lee Jay Lorenzen, who worked at Xerox and wished to create a cheaper, less resource-intensive alternative to the Xerox Star, which he got to do at DRI after

https://www.osnews.com/story/143393/history-of-the-gem-desktop-environment/

#RetroComputing

History of the GEM desktop environment

The 1980s saw a flurry of graphical user interfaces pop up, almost all of them in some way made by people who got to see the work done by Xerox. Today's topic is no exception - GEM was developed by Lee Jay Lorenzen, who worked at Xerox and wished to create a cheaper, less resource-intensive alternative to the Xerox Star, which he got to do at DRI after

https://www.osnews.com/story/143393/history-of-the-gem-desktop-environment/

#RetroComputing

North star coffee, then you need a z80,cpm and s100 bus start in the morning.

#RetroComputing

I wanted to find a small niche hobby coding project that approximately nobody would care about.

I'm tooting about it now, and I don't expect you to care.

I want to use m68k-linux-gnu-as cross-assembler, but it doesn't support the Motorola syntax the original Amiga tools did.

How hard can it be to write a preprocessor that converts vasm mot syntax module compatible assembly to GNU as?!

Turns out, less trivial than I thought.

#Amiga #RetroComputing #m68k#Assembly

I wanted to find a small niche hobby coding project that approximately nobody would care about.

I'm tooting about it now, and I don't expect you to care.

I want to use m68k-linux-gnu-as cross-assembler, but it doesn't support the Motorola syntax the original Amiga tools did.

How hard can it be to write a preprocessor that converts vasm mot syntax module compatible assembly to GNU as?!

Turns out, less trivial than I thought.

#Amiga #RetroComputing #m68k#Assembly

Pretty good #C64 hardware rundown/comparison for the uninitiated.

https://www.youtube.com/watch?v=qz8EzWTb4so

#Commodore #RetroComputing#NeoRetro

Pretty good #C64 hardware rundown/comparison for the uninitiated.

https://www.youtube.com/watch?v=qz8EzWTb4so

#Commodore #RetroComputing#NeoRetro

Me, looking at the 8008/8080/Z80 instruction sets: "bah, why do you need conditional calls and conditional returns when the conditional jumps are already more than enough?"

Me, coding in 68000: "I really with I had conditional calls and conditional returns, relying on conditional jumps makes the code harder to read than necessary."

I am never happy.

#RetroComputing#Assembly

Me, looking at the 8008/8080/Z80 instruction sets: "bah, why do you need conditional calls and conditional returns when the conditional jumps are already more than enough?"

Me, coding in 68000: "I really with I had conditional calls and conditional returns, relying on conditional jumps makes the code harder to read than necessary."

I am never happy.

#RetroComputing#Assembly

In my little world of #RetroComputing, I have stumbled across minor issues in some of the tools that I use.

I've had two cases so far where maintainers very quickly took my suggestion and made it available in their main branch. I've also had one where I haven't heard back from the maintainer, i.e. where I'm going to need to maintain my own fork (for #RiscV compatibility). And that's OK. Beyond being glad that I got help, I'm glad that the original authors allow me also to do the work myself.