diff options
Diffstat (limited to 'ROMs/_old/hello_world.asm')
| -rw-r--r-- | ROMs/_old/hello_world.asm | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/ROMs/_old/hello_world.asm b/ROMs/_old/hello_world.asm new file mode 100644 index 0000000..1d812fb --- /dev/null +++ b/ROMs/_old/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
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