Py502

a Python CPU emulator with a custom instruction set, and an ASM compiler

What Doin'?

I am currently working on a C compiler for this custom CPU architecture. I am also going to add characters to my ASM compiler so you can do stuff like

message:
  .asciiz db "Hello, World!", 0x00 ; null terminated

Problem??

I've included a broken ASM program, try to fix it with the error messages from the compiler, and let me know where i can improve the messages

main:
    ldw a, 0xFF     ;  load 255 to A register, Unused
    str a, 0x0F      ;  will cause an error because its writing to program memory
                    ;  You will have to make the address bigger than the program
    int 0x00        ;  interupt to print a register to terminal as a char (debug)
    
    ldw a, 0        ; will be the graphics mode
    str a, 0xF0     ; copy A register to memory address   
    
    ldw a, 800      ; screen width
    str a, 0xF1     ; copy A register to memory address     
    
    ldw a, 600      ; screen height
    str a, 0xF2     ; copy A register to memory address
    jsr _init_graphics_mode
    
    
    
init_graphics_mode:
    push a
    push b
    push c
    
    ldw g, 0xFF ; This is never used
    
    ldr a, 0xF0 ; copy data from memory address to register 'A'
    ldr b, 0xF1 ; copy data from memory address to register 'B'
    ldr c, 0xF2 ; copy data from memory address to register 'C'
    
    int 0x70    ; all interupts in 0x70 - 0x7F are for graphics, 
                ; only 0x70 to 0x72 are implemented
                
    pop b
    pop a
    
    ret

Interupts

0x00 -> print register a as char 0x01 -> print register a as int 0xFF -> Halt 0xFE -> Error Interupt 0xF6 -> put keycode of currently pressed key in A register and but a value (bool)(0 or 1) into b register to indicate whether it is the first time this key has been pressed. 0x70 -> Init graphics, (A) mode (B) X resolution (C) Y Resulution 0x71 -> Set Pixel, (bitmap mode) (A) Color (0x000000 to 0xFFFFFF) (B) x position (C) y position 0x72 -> Set Char, (Text Mode) (A) Character Code (B) Cursor Position (C) Color (0x000000 to 0xFFFFFF)

! ALLL FILESYSTEM DRIVE NUMBER ARE LOCAL FILES ! drive( drive number (0 to 9)).bin "drive8.bin" drive number -> ( 0 to 9 ) sector number -> ( 0 to 15 ) byte offset -> ( 0 to 254 )

0x80 -> read byte from disk (A) drive number (B) sector number (C) byte offset moves output to A register 0x81 -> write byte from disk (A) drive number (B) sector number (C) byte offset (D) byte to write

Example error messages for the ASM Compiler