gistfile1.asm

.nolist
#include "kernel.inc" ; Kernel routines like loadLibrary
#include "macros.inc"
#include "keys.inc" ; Key codes
#include "libtext.inc" ; For drawing text
#include "applib.inc" ; For drawing UI
.list
; Header
    .db %00000010
    .db 50 ; Stack size
; Program
.org 0
    ; Get hardware locks
    call getLcdLock
    call getKeypadLock

    ; Load dependencies
    kld de, libtextPath
    call loadLibrary
    kld de, applibPath
    call loadLibrary
    
    ; Draw window
    xor a ; Window flags (defaults)
    kld hl, windowTitle
    applib(drawWindow)
    
    ; Draw text
    ld de, $0208 ; D = X, E = Y
    kld hl, helloWorld
    libtext(drawString)
    
    ; Loop until Clear is pressed
loop:
    applib(appGetKey) ; Same as getKey, but watches for UI hotkeys
    cp kClear
    ret z
    jr loop
    
helloWorld:
    .db "Hello, world!", 0
windowTitle:
    .db "Hello World", 0
libtextPath:
    .db "/lib/libtext", 0
applibPath:
    .db "/lib/applib", 0