dos33fsprogs/graphics/gr/mode7/checkerboard_lookup.s
Vince Weaver e0febd1a90 demos: more work
keep making git mistakes urgh
2021-01-05 22:52:10 -05:00

22 lines
515 B
ArmAsm

;====================
; lookup_map
;====================
; finds value in space_x.i,space_y.i
; returns color in A
; CLOBBERS: A,Y
lda SPACEX_I ; 3
sta spacex_label+1 ; self modifying code, LAST_SPACEX_I ; 4
lda SPACEY_I ; 3
sta spacey_label+1 ; self modifying code, LAST_SPACEY_I ; 4
lda SPACEY_I
eor SPACEX_I
and #$1
beq @black
@white:
lda #$ff
@black:
sta map_color_label+1 ; self-modifying