Learning 6502 assembly language

[+SpiceWare]

I ran across Easy 6502 yesterday, seems to be rather nice introduction to learning the 6502 (which is basically the same CPU as the 6507 used in the Atari 2600). I really like the use of the 6502 simulator, you can manipulate the example code on the web page and see the results right there.

 

Initial example

 

After clicking Assemble - note the assembler's output in the shaded box

 

After clicking Run - note the 3 colored dots that showed up in the black box:

 

After making changes then clicking Assemble and Run

 

After clicking Hexdump

 

After clicking Disassembly

 

It wraps up with a game of snake ( play using the keys WASD )

Edited July 28, 2015 by SpiceWare

[roryjr]

Cool. I used to play around with programs on my Atari 600XL and later my 130XE. I tried to add machine language subroutines in the vertical blank, bur could never get them to work right. Maybe this would have helped.

[minimoose]

That was really fun, but the "Our First Program" was really boring. Here's my 2nd program:

 

LDX #$e

TXA

STA $0200,X

STA $0240,Y

STA $0280,X

STA $0320,Y

STA $0360,X

STA $0400,Y

STA $0440,X

STA $0480,Y

STA $0500,X

INX

DEY

STA $0200,Y

STA $0240,X

STA $0280,Y

STA $0320,X

STA $0360,Y

STA $0400,X

STA $0440,Y

STA $0480,X

STA $0500,Y

INX

DEY

INX

DEY

INX

DEY

INX

DEY

INX

DEY

INX

DEY

JMP $0602

That's a lot more fun to watch, and you can mess around adding INX and DEY opcodes to get completely different effects.

-mini

[Papa]

KYEWT!

[Jinroh]

Neat, seems very similar to 6502asm.com's beta upgrade. I wonder if they're related at all.

 

http://6502asm.com/beta/index.html

[+SpiceWare]

They're the same, though I do like all the example programs you can quickly call up.

 

I will note the comment in Spacer.

 

 

Ps: this game runs awfully slow =)

 

is not at all true for me, it's much too fast to play on my Mac Pro.

[Jinroh]

Ah nice they are!

 

If I remember right Spacer was a holdout from the OLD 6502ASM version they were running in 2004/2005 whenever that was, and it did run really slowly at that time. After the simulator was optimized now it runs like a champ.

 

I made a Breakout game for the site ages ago, but doesn't look like it was catalogued anywhere. I believe it was on the old forum they had but I don't think it's there anymore.

 

They're the same, though I do like all the example programs you can quickly call up.

 

I will note the comment in Spacer.

 

 

 

is not at all true for me, it's much too fast to play on my Mac Pro.

Edited August 20, 2015 by Jinroh