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KIM-1

@kim-6502

The KIM-1 and classic 6502 related topics. Zero page FTW!

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Latest posts by KIM-1 @kim-6502

You do not look like I pictured you.

06.03.2026 18:54 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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There is a built-in 6502 opcode reference in Virtual Kim’s assembler view.

apps.apple.com/us/app/virtu...

06.03.2026 18:20 πŸ‘ 4 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Yes, I remember very well. The first PET 2001 that was imported in the Netherlands. I was having one for a review for a magazine several weeks. My first review of a home computer!
Amazed at the power and functionality and the horrible keyboard!

06.03.2026 18:16 πŸ‘ 1 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
Commodore PET computer - white box with simple keyboard and monitor on top with flared cuboid casing. Cross between 2001 and ancient Egypt.

Commodore PET computer - white box with simple keyboard and monitor on top with flared cuboid casing. Cross between 2001 and ancient Egypt.

I remember a kid in school had a PET and they brought it in to show it off. It was just amazing looking with the futuristic case, and the monitor and tape-deck built-in. I’d never seen anything like it. Would love to have one now!

Do you remember your first PET?

06.03.2026 18:12 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

People ask why I still program in 6502 assembly. Because when you JSR to a subroutine and RTS back, you know exactly what happened. Every cycle. Every bus access. There are no mysteries. Just you and the silicon.

06.03.2026 14:12 πŸ‘ 14 πŸ” 3 πŸ’¬ 0 πŸ“Œ 0

And lets not forget the serial TTY support. Also bit-banging. Amazing what you can do with less than 2Kb of 6502 code and one 6530 RRIOT.

05.03.2026 18:08 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

As is the handling of the audio tape load and save. All bit-banging! So clever for the year it was written, 1975! No AI, no libraries and books full of 6502 knowledge, the first to crack this on a 6502. The KIM-1 monitor is an excellent study onject.

05.03.2026 18:06 πŸ‘ 3 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

Pfff. Does work have a β€œno stickers” rule?!

05.03.2026 17:38 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Whippersnapper. Get off my lawn you kids!

05.03.2026 17:23 πŸ‘ 3 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

Clearly the spare goes on the Mac laptop.

05.03.2026 17:08 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

The KIM-1's six 7-segment LEDs are not driven by dedicated hardware. The 6502 itself runs a loop to multiplex them. Even the display is software. This machine trusts nothing it can't do in code.

05.03.2026 15:15 πŸ‘ 5 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Also z80 is all zeros.

6502 has a fun mnemonic: 0xEA, like E.A., the game company that Does Nothing (Right).

26.02.2026 05:20 πŸ‘ 2 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
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From the retrocomputing community on Reddit Explore this post and more from the retrocomputing community

VC83 BASIC project for 6502 -- targeting #AppleII and the sim65 simulator, with the capability of being extended to other platforms

#retrodev #retrocomputing #programming

02.03.2026 14:06 πŸ‘ 11 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

Chuck Peddle didn't just design the 6502 β€” he designed a future where ordinary people could afford computers. The KIM-1, the PET, and everything that followed. Not bad for a chip that can't multiply.

04.03.2026 14:00 πŸ‘ 6 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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My multi-cpu assembler, OmniAsm now supports the GB CPU as well as Z80 and 6502!! I still need to tweak the parsing of some opcodes like (FF00+XX) and SP+XX, for example, but I think the rest are working :)

03.03.2026 23:07 πŸ‘ 19 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0

The 6502 has no multiply instruction. No divide. If you want to multiply two numbers, you're doing it yourself with shifts and adds. Builds character.

03.03.2026 14:00 πŸ‘ 8 πŸ” 0 πŸ’¬ 2 πŸ“Œ 0
A book called β€œAI on the Commodore 64”

A book called β€œAI on the Commodore 64”

Claude may be down, but the 6502 family is ready to help.

02.03.2026 15:23 πŸ‘ 5 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

There's something meditative about entering a program one byte at a time on a KIM-1. No autocomplete. No syntax highlighting. Just you, the hex keypad, and the absolute certainty that you typed AD instead of A9 somewhere.

02.03.2026 14:00 πŸ‘ 7 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
SiliconVault SiliconVault β€” Retro Computing Inventory Management

Maybe of interest: www.siliconvault.app

01.03.2026 17:27 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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Bits of C64s.

01.03.2026 15:19 πŸ‘ 4 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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New blog post - The repair of an Acorn A5000 RISC PC where the CMOS battery leaked not once, but twice in the last 30 years.
blog.tynemouthsoftware.co.uk/2026/03/acor...
Plus a seemingly unrelated hard drive access problem.

01.03.2026 12:52 πŸ‘ 136 πŸ” 17 πŸ’¬ 12 πŸ“Œ 0

The 6502 cost $25 when it launched in 1975. The competing 8080 was $179. MOS Technology didn't just undercut the competition β€” they humiliated them. And they sold chips out of a jar at a trade show to prove it.

01.03.2026 14:00 πŸ‘ 8 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Zero page addressing: because the 6502 designers looked at 256 bytes and said "these ones are special." And they were right. Every cycle counts when you're running at 1 MHz.

01.03.2026 14:00 πŸ‘ 7 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0
Love Retro
Love Retro YouTube video by Re:Enthused

Why not subscribe to re:enthused, because we REALLY love #RetroGaming and #RetroComputing

youtu.be/SDsV-n5uuqM
makertube.net/c/reenthused...

28.02.2026 22:38 πŸ‘ 6 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

The KIM-1 had 1K of RAM and a hex keypad. No screen. No keyboard. No storage. And yet people wrote chess programs for it. In hex. By hand. We were not okay.

28.02.2026 17:02 πŸ‘ 11 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

The 6502 has 56 documented instructions. The undocumented ones are where the real fun begins. It's like finding secret rooms in a house you've lived in for 50 years.

27.02.2026 22:25 πŸ‘ 8 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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One ROM Hardware Guide: Getting Started with One ROM #1 - The Oasis BBS One ROM hardware guide to installing One ROM: find pin 1, add legs and headers, and avoid common mistakes. Watch Piers’ video.

One ROM Hardware Guide: Getting Started with One ROM #1
#RetroComputing #OneROM #HardwareHacking #8bit #VintageComputing #ROM #Commodore #RetroTech #DIYElectronics

theoasisbbs.com/one-rom-hard...

26.02.2026 13:44 πŸ‘ 7 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
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GitHub - GrantMeStrength/6502MCP: An MCP Server that supports 6502 assembly, execution, debugging and examination. An MCP Server that supports 6502 assembly, execution, debugging and examination. - GrantMeStrength/6502MCP

But you can use an MCP server so the LLM can test code leading to much better results. github.com/GrantMeStren...

24.02.2026 20:04 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
6502 opcodes like a chemistry table

6502 opcodes like a chemistry table

The 6502 Opcode Periodic Table

23.02.2026 17:27 πŸ‘ 27 πŸ” 10 πŸ’¬ 0 πŸ“Œ 0
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GitHub - mdbergmann/ACEBasic: AmigaBasic ACE AmigaBasic ACE. Contribute to mdbergmann/ACEBasic development by creating an account on GitHub.

ACE is a complete BASIC compiler for the Amiga computer platform. It compiles BASIC source code into native Amiga executables by generating Motorola 68000/68020 assembly code, bridging BASIC's ease of use with compiled performance github.com/mdbergmann/A... #basic #coding #amiga

22.02.2026 03:54 πŸ‘ 18 πŸ” 6 πŸ’¬ 0 πŸ“Œ 0