dos33fsprogs/megademo/hgr.s

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HGR_SHAPE = $1A
HGR_SHAPE_H = $1B
HGR_BITS = $1C
HGR_COUNT = $1D
HMASK = $30
DSCTMP = $9D
HGR_DX = $D0
HGR_DX_H = $D1
HGR_DY = $D2
HGR_QUADRANT = $D3
HGR_E = $D4
HGR_E_H = $D5
HGR_X = $E0
HGR_X_H = $E1
HGR_Y = $E2
;HGR_COLOR = $E4
HGR_HORIZ = $E5
HGR_PAGE = $E6
TXTCLR = $C050
MIXSET = $C053
LOWSCR = $C054
MIXCLR = $C052
HISCR = $C055
;.align $100
.assert >hgr = >hgr_after, error, "hgr crosses page"
;==========================
; HGR
;==========================
hgr:
; F3E2
lda #$20 ; HIRES Page 1 at $2000
bit LOWSCR ; BIT SW.LOWSCR Use PAGE1 ($C054)
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; bit MIXSET ; BIT SW.MIXSET (Mixed text)
sethpg:
; F3EA
sta HGR_PAGE
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; lda HIRES
; lda TXTCLR
hclr:
lda #0 ; black background
sta HGR_BITS
bkgnd:
; F3F6
lda HGR_PAGE
sta HGR_SHAPE+1
ldy #0
sty HGR_SHAPE
bkgnd_loop:
lda HGR_BITS
sta (HGR_SHAPE),y
jsr color_shift
iny
bne bkgnd_loop
inc HGR_SHAPE+1
lda HGR_SHAPE+1
and #$1f ; see if $40 or $60
bne bkgnd_loop
rts
hgr_after:
.assert >msktbl = >msktbl_after, error, "msktbl crosses page"
msktbl: .byte $81,$82,$84,$88,$90,$A0,$C0 ; original
msktbl_after:
.align $100
.assert >hposn = >hposn_after, error, "hposn crosses page"
;====================================================
; HPOSN
; time = 9 + 61 + 31 + 22 + 42 + 22 + 23 = 210
hposn:
; F411: move values into expected zp locations
sta HGR_Y ; 3
stx HGR_X ; 3
sty HGR_X+1 ; 3
;===========
; 9
; calc y-position addr. no lookup table?
pha ; 3
and #$C0 ; 2
sta GBASL ; 3
lsr ; 2
lsr ; 2
ora GBASL ; 3
sta GBASL ; 3
pla ; 4
sta GBASH ; 3
asl ; 2
asl ; 2
asl ; 2
rol GBASH ; 5
asl ; 2
rol GBASH ; 5
asl ; 2
ror GBASL ; 5
lda GBASH ; 3
and #$1f ; 2
ora HGR_PAGE ; 3
sta GBASH ; 3
;============
; 61
; F438
; divide/mod 16-bit x poisition by 7
; incoming, X=(y,x)
; outgoing y=q, a=r
; Divide by 7 (From December '84 Apple Assembly Line)
txa ; 2
clc ; 2
sta HGR_HORIZ ; 3
lsr ; 2
lsr ; 2
lsr ; 2
adc HGR_HORIZ ; 3
ror ; 2
lsr ; 2
lsr ; 2
adc HGR_HORIZ ; 3
ror ; 2
lsr ; 2
lsr ; 2
; x/7 is in A
;============
; 31
; calculate remainder
clc ; 2
sta HGR_HORIZ ; 3
asl ; 2
adc HGR_HORIZ ; 3
asl ; 2
adc HGR_HORIZ ; 3
; HGR_HORIZ=x/7, A=HGR_HORIZ*7
; calculate remainder by X-(Q*7)
sec ; 2
eor #$ff ; 2
adc HGR_X ; 3
; A = remainder ;===========
; 22
;============================================================================
cpy #0 ; 2
beq done_mod_nop_23 ; 3
;==========
; 5
theres_high:
; -1
clc ; 2
adc #4 ; make remainder match ; 2
pha ; 3
lda HGR_HORIZ ; 3
adc #36 ; 2
sta HGR_HORIZ ; 3
pla ; 4
cmp #7 ; 2
bcc done_mod_nop14 ; blt ; 3
;============
; 23
; -1
sec ; 2
sbc #7 ; 2
inc HGR_HORIZ ; 5
ldy HGR_HORIZ ; nop ; 3
jmp done_mod ; 3
;============
; 14
;===========================
; Y=HIGH,bcc = 5+23+ 14 = 42
; Y=HIGH,bcs = 5+23+ 14 = 42
; Y=LOW = 5 + 14+23 = 42
done_mod_nop_23:
inc HGR_HORIZ,X ; (nop) ; 6
dec HGR_HORIZ,X ; (nop) ; 6
ldy HGR_HORIZ ; (nop) ; 3
ldy HGR_HORIZ ; (nop) ; 3
ldy HGR_HORIZ ; (nop) ; 3
nop ; 2
done_mod_nop14:
inc HGR_HORIZ,X ; (nop) ; 6
dec HGR_HORIZ,X ; (nop) ; 6
nop ; 2
done_mod:
ldy HGR_HORIZ ; 3
tax ; 2
lda msktbl,x ; 4+
sta HMASK ; 3
tya ; 2
lsr ; 2
lda HGR_COLOR ; 3
sta HGR_BITS ; 3
;===========
; 22
bcs color_shift ; 3
; cs = 3+20
;-1
; need 23 = 2+6+X = 15
inc HMASK,X ; nop ; 6
dec HMASK,X ; nop ; 6
lda HMASK ; nop ; 3
rts ; 6
;===========
; 23
;===================================
; COLOR_SHIFT
;===================================
; positive = 7+(7)+6 = 20
; negative = 7+ 7 +6 = 20
color_shift: ; F47E
asl ; 2
cmp #$c0 ; 2
bpl done_color_shift ; 3
; -1
lda HGR_BITS ; 3
eor #$7f ; 2
sta HGR_BITS ; 3
rts ; 6
done_color_shift:
lda HGR_BITS ; nop ; 3
nop ; 2
nop ; 2
rts ; 6
hposn_after:
;.align $100
.assert >hplot0 = >hplot0_after, error, "hplot0 crosses page"
;=====================================
; HPLOT0
;=====================================
; point in (YX),A
; 244 cycles
hplot0:
; F457
jsr hposn ; 6+210
lda HGR_BITS ; 3
eor (GBASL),y ; 5+
and HMASK ; 3
eor (GBASL),y ; 5+
sta (GBASL),y ; 6
rts ; 6
;============
; 244
hplot0_after:
.assert >hcolor_equals = >hcolor_equals_after, error, "hce crosses page"
;=============================
; HCOLOR_EQUALS
;=============================
; Color in X
; 13 cycles
hcolor_equals:
; F6E9
; TODO: mask to be less than 8
lda colortbl,x ; 4+
sta HGR_COLOR ; 3
rts ; 6
colortbl:
.byte $00,$2A,$55,$7F,$80,$AA,$D5,$FF
hcolor_equals_after: