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Jason Turner 24012c1ff7 Fix use of address 1 to literal 1 for skip instructions
Thank you to the viewers who pointed out the issue at the
end of the stream.

At this point, simple code works, but the conditional
from the joystick input does not seem to work yet.

 * also add location header for linker
 * also filter errors and directives better
2021-04-22 18:54:00 -06:00
examples Fix use of address 1 to literal 1 for skip instructions 2021-04-22 18:54:00 -06:00
src Fix use of address 1 to literal 1 for skip instructions 2021-04-22 18:54:00 -06:00
CMakeLists.txt Almost working programs with AVR conversion 2021-04-22 15:52:35 -06:00
make_file.sh Reorganize file structure 2016-08-24 16:55:08 -06:00
readme.md Add some docs and test and cmake support 2016-07-07 15:48:27 -06:00

About

Attempts to translate x86 assembly into mos6502 assembly.

Why?

Why not? I figured I just barely knew some x86 and some 6502, so why not learn some more about both. Besides, this project can actually have some interesting applications.

Example

After compilation (requires a full C++14 compiler), you can run something like this:

// test.asm
main:
	movb	$1, 53280
	xorl	%eax, %eax
	ret
cat test.asm | x86-to-6502

And get this output:

main:
	ldy #$1
	sty 53280
	lda $00
	rts 

Caveats

  • Nothing is guaranteed. This could break your computer. Who knows?
  • All values are truncated to 8 bit. We have no support for 16bit math or pointers yet
  • Only as many instructions are supported as I have needed to support to get my test cases working

To Do

Everything

Well, lots of things.

Better code organization

I really had no idea what I was doing when I started this. So, like all code, it's going to need some improvements along the way to make it more organized and more maintainable.

Improvements

  • Keep track of input source lines and add comments in output to show where lines came from, for learning / debugging purposes
  • Better / more efficient translation
  • Support for 16bit math? Maybe? We need to at least be able to do 16bit pointer math
  • Consider supporting the "Sweet 16" virtual 16bit CPU that Woz designed?
  • Maybe for 16bit operation we try to detect if the input code is working on 8bit registers or 16+bit registers and do the right thing?
  • Support for more CPU instructions
  • A test suite