Hello World: compile, run and debug on openMSX

Gilbert Francois Duivesteijn

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The picture above shows the final result on a real MSX, running from cartridge. Follow the steps below and you have it running yourself in minutes.

Step 1: Watch the tutorial from ChibiAkumas to know what the code is doing:

Lesson H3 - Hello World on the MSX by ChibiAkumas

Step 2: Type in the code below and save to a file named helloworld.asm. Link to GitHub

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; ==[ Constants ]===============================================

ORGADR  equ $4000
CHPUT   equ $00A2
CHMOD   equ $005f
RomSize equ $4000

; ==[ Header ]==================================================

    ; Place header inside the binary.
    org ORGADR
    ; ROM header
    db "AB"
    dw Main
    dw 0, 0, 0, 0, 0, 0

; ==[ Program ]=================================================

FileStart:
Main:
    ; set VDP to screen 0
    ld a, 0
    call CHMOD
    ; print "Hello world" on screen
    ld hl, helloWorld
    call PrintStr
    call NewLn
    call Finished

PrintStr:
    ld a, (hl)
    cp 0
    ret z
    inc hl
    call CHPUT
    jr PrintStr

NewLn:
    push af
    ld a, 13
    call CHPUT
    ld a, 10
    call CHPUT
    pop af
    ret

Finished:
  di
  halt

helloWorld:
    db "Hello world!", 0

; ==[ ROM Padding ]=============================================

FileEnd:
    ds $4000 + RomSize - FileEnd, 255

Step 3: Compile

with VASM

$ vasmz80_oldstyle helloworld.asm -chklabels -nocase -Dvasm=1 -Fbin -L out.sym -o out.rom

or with Glass (you can choose)

$ java -jar Glass.jar helloworld.asm -L out.sym out.rom

Step 4: run with openMSX

$ <path to>/openmsx -machine C-BIOS_MSX1_EU -cart out.rom

Step 5: connect with openMSX Debugger

• Open the openMSX debugger
• Press Connect
• To see the symbols and have a better experience when stepping through the source file, click on sym button and add the file out.sym.
• Set breakpoints (if you want) and click in the menu on System -> Reboot Emulator

Step 6: Flash a cartridge, the MegaFlashROM and run your program on a MSX like a pro:

• Copy the file out.rom to a microSD card

• Insert the microSD card in the MegaFlashRom, start your MSX.

• In the Nextor (MSX-DOS alike) prompt, type:

  B:> opfxsd out.rom
  

• Reboot the computer and.... congratulations with your first self created ROM on cartridge!

• To erase the ROM on the cartridge, reboot the machine and hold the arrow up key. In the recovery mode, choose F1 - Erase MegaFlashROM. Now it is ready for your next program.