dos33fsprogs/games/lemm/hgr_box.s
2022-03-27 15:40:20 -04:00

55 lines
772 B
ArmAsm

;=================================
; Simple HGR box
;=================================
; only 1 7-bit block wide
; (X,A) to (X,A+Y) where X is xcoord/7
hgr_box:
; don't handle run of 0
cpy #0
beq done_hgr_box
; get initial ROW into (GBASL)
sta box_row_smc+1 ; save current A
stx box_x1_smc+1
ldx HGR_COLOR ; get colors
lda hgr_colortbl,X
sta HGR_BITS
tya
tax ; put line count into X
hgr_box_loop:
box_row_smc:
ldy #$dd ; get row info for Y1 into GBASL/GBASH
lda hposn_high,Y
hgr_box_page_smc:
eor #$00
sta GBASH
lda hposn_low,Y
sta GBASL
lda HGR_BITS
box_x1_smc:
ldy #$dd
sta (GBASL),Y
inc box_row_smc+1
dex
bne hgr_box_loop
done_hgr_box:
rts
hgr_box_page_toggle:
lda hgr_box_page_smc+1
eor #$60
sta hgr_box_page_smc+1
rts