185 lines
3.7 KiB
ArmAsm
185 lines
3.7 KiB
ArmAsm
;===============================================
|
|
; Move Letters
|
|
;===============================================
|
|
; Normal P0 =6+13+2+22+46+37 = 126
|
|
; Normal P1 =6+13+2+22+46+37 = 126
|
|
; End of line =6+13+2+22+46+9+(28) = 126
|
|
; Next line =6+13+5+14+34+(26+28) = 126
|
|
; done entirely =6+13+5+(6+42+26+28) = 126
|
|
; Waiting =6+7+(11+6+42+26+28) = 126
|
|
|
|
; all forced to be 126
|
|
|
|
move_letters:
|
|
ldy WAITING ; 3
|
|
beq not_waiting ; 3
|
|
;============
|
|
; 6
|
|
|
|
;-1
|
|
dec WAITING ; 5
|
|
jmp wait_it_out ; 3
|
|
;===========
|
|
; 7
|
|
|
|
not_waiting:
|
|
; load letter from pointer, save into LETTER
|
|
|
|
ldy #0 ; 2
|
|
lda (LETTERL),Y ; 5
|
|
sta LETTER ; 3
|
|
|
|
; if high bit set, is special case
|
|
bmi letter_special ; 3
|
|
;==========
|
|
; 13
|
|
|
|
; just regular letter
|
|
|
|
;-1
|
|
lda LETTERY ; get letter Y ; 3
|
|
bmi letter_page1
|
|
;==========
|
|
; 2
|
|
|
|
letter_page0: ; -1
|
|
asl ; map to memory address ; 2
|
|
tay ; 2
|
|
lda gr_offsets,Y ; lookup low-res memory address ; 4
|
|
sta BASL ; store out low byte of addy ; 3
|
|
lda gr_offsets+1,Y ; look up high byte ; 4
|
|
sta BASH ; 3
|
|
lda #0 ; cycle-killer ; 2
|
|
jmp letter_erase ; 3
|
|
;==========
|
|
; 22
|
|
|
|
letter_page1:
|
|
asl ; map to memory address ; 2
|
|
tay ; 2
|
|
lda gr_offsets,Y ; lookup low-res memory address ; 4
|
|
sta BASL ; store out low byte of addy ; 3
|
|
lda gr_offsets+1,Y ; look up high byte ; 4
|
|
clc ; 2
|
|
adc #$4 ; adjust to page1 ; 2
|
|
sta BASH ; 3
|
|
;==========
|
|
; 22
|
|
|
|
;============================
|
|
letter_erase:
|
|
ldy LETTERX ; nop ; 3
|
|
nop ; nop ; 5
|
|
|
|
ldy #0 ; erase old char with space ; 2
|
|
lda #' '|$80 ; 2
|
|
ldy LETTERX ; 3
|
|
sta (BASL),Y ; 6
|
|
|
|
dey ; draw new char ; 2
|
|
sty LETTERX ; 3
|
|
lda LETTER ; 3
|
|
ora #$80 ; 2
|
|
ldy LETTERX ; 3
|
|
sta (BASL),Y ; 6
|
|
|
|
lda LETTERX ; see if we are at destination ; 3
|
|
cmp LETTERD ; 3
|
|
beq letter_next ; 3
|
|
;===========
|
|
; 46
|
|
|
|
;-1
|
|
lda #0 ; 2
|
|
lda #0 ; 2
|
|
jmp waste_28 ; 3
|
|
;==========
|
|
; 9
|
|
letter_next:
|
|
clc ; 16-bit inc letter pointer ; 2
|
|
lda LETTERL ; 3
|
|
adc #1 ; 2
|
|
sta LETTERL ; 3
|
|
lda LETTERH ; 3
|
|
adc #0 ; 2
|
|
sta LETTERH ; 3
|
|
|
|
inc LETTERD ; inc destination X ; 5
|
|
lda #39 ; start at right of screen ; 2
|
|
sta LETTERX ; 3
|
|
rts ; 6
|
|
;===========
|
|
; 37
|
|
|
|
letter_special:
|
|
cmp #$ff ; handle FF, we're done ; 2
|
|
beq letter_done ; 3
|
|
;==========
|
|
; 5
|
|
|
|
|
|
; -1
|
|
and #$7f ; clear top ; 2
|
|
sta WAITING ; this is waiting value ; 3
|
|
|
|
ldy #1 ; otherwise, Y,X pair ; 2
|
|
lda (LETTERL),Y ; get Y, put in LETTERY ; 5
|
|
sta LETTERY ; 3
|
|
;===========
|
|
; 14
|
|
|
|
iny ; get dest ; 2
|
|
lda (LETTERL),Y ; 5
|
|
sta LETTERD ; put in LETTERD ; 3
|
|
|
|
clc ; skip 3 bytes to begin of letters ; 2
|
|
lda LETTERL ; 16-bit add ; 3
|
|
adc #3 ; 2
|
|
sta LETTERL ; 3
|
|
lda LETTERH ; 3
|
|
adc #0 ; 2
|
|
sta LETTERH ; 3
|
|
lda LETTERH ; waste ; 3
|
|
jmp waste_26 ; 3
|
|
|
|
;===========
|
|
; 34
|
|
|
|
wait_it_out:
|
|
; wait 11
|
|
inc BLARGH ; 5
|
|
lda LETTERH ; 3
|
|
lda LETTERH ; 3
|
|
|
|
letter_done:
|
|
lda LETTERH ; 3
|
|
lda LETTERH ; 3
|
|
|
|
waste_42:
|
|
ldx #0 ; 2
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
waste_26:
|
|
ldx #0 ; 2
|
|
ldx #0 ; 2
|
|
ldx #0 ; 2
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
|
|
waste_28:
|
|
ldx #0 ; 2
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
inc BLARGH ; 5
|
|
rts ; 6
|
|
|