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authorMelodi <62381002+Melodi17@users.noreply.github.com>2025-08-06 22:36:34 +1000
committerMelodi <62381002+Melodi17@users.noreply.github.com>2025-08-06 22:36:34 +1000
commit7a8d2bcd75d88a5429937bf551878c55e1dcf0fd (patch)
tree81bc1f259fb8678513aa8b214df4ef72720bb585 /ROMs/hello_world.asm
parent16f3cb74564cf7c19da6e13666c98aca36094716 (diff)
moved everything to seperate projects, and started compiler work + push and pop instructions added
Diffstat (limited to 'ROMs/hello_world.asm')
-rw-r--r--ROMs/hello_world.asm42
1 files changed, 42 insertions, 0 deletions
diff --git a/ROMs/hello_world.asm b/ROMs/hello_world.asm
new file mode 100644
index 0000000..1d812fb
--- /dev/null
+++ b/ROMs/hello_world.asm
@@ -0,0 +1,42 @@
+.org $1FFF
+JMP program
+
+font:
+ .include "font.bin"
+
+program:
+ MOV 0, V0 ; Load character #12
+ MOV 0, V1 ; X position
+ MOV 0, V2 ; Y position
+ MOV 1, V3 ; Color (1 = white)
+ CALL write_char ; Call function to write character
+ SUS
+
+write_char:
+ ; V0: Character to write
+ ; V1: X position
+ ; V2: Y position
+ ; V3: Color
+ ; Write a character to the screen at (V1, V2) with color V3
+
+ MUL V0, 64 ; V0 = Character * 64 (character size)
+ MOV AX, V0 ; Store result back into character
+
+ MUL V2, 64
+ ADD AX, V1
+ MOV AX, V4 ; V4 = X position + Y position * 64 (screen index)
+
+ MOV V4, [$EFFF] ; Debug
+
+ MOV [V0 + $2003], V5 ; Read character (1FFF + 4 since jump address is 1FFF)
+ MOV V5, [$EFFF] ; Debug
+ AND V5, $01 ; Mask to get first bit (color)
+ MOV DX, V5
+ MOV V5, [$EFFF] ; Debug
+ MUL V5, V3 ; V5 = Character * Color (color index)
+ MOV AX, V5 ; Store result into V5
+
+ MOV V5, [$EFFF] ; Debug
+
+ MOVB V5, [V4 + $402F] ; Write character to screen memory
+ RET \ No newline at end of file