dos33fsprogs/demosplash2019/text_print.s
2019-11-15 22:28:28 -05:00

60 lines
955 B
ArmAsm

;================================
; move_and_print
;================================
; get X,Y from OUTL/OUTH
; then print following string to that address
; stop at NUL
; convert to APPLE ASCII (or with 0x80)
; leave OUTL/OUTH pointing to next string
move_and_print:
ldy #0
lda (OUTL),Y
sta CH
iny
lda (OUTL),Y
asl
tay
lda gr_offsets,Y ; lookup low-res memory address
clc
adc CH ; add in xpos
sta BASL ; store out low byte of addy
lda gr_offsets+1,Y ; look up high byte
adc DRAW_PAGE ;
sta BASH ; and store it out
; BASH:BASL now points at right place
clc
lda OUTL
adc #2
sta OUTL
lda OUTH
adc #0
sta OUTH
;================================
; print_string
;================================
print_string:
ldy #0
print_string_loop:
lda (OUTL),Y
beq done_print_string
ora #$80
sta (BASL),Y
iny
bne print_string_loop
done_print_string:
iny
clc
tya
adc OUTL
sta OUTL
lda OUTH
adc #0
sta OUTH
rts