dos33fsprogs/graphics/gr/rotozoom/rotozoom_texture.s
2023-08-15 14:48:24 -04:00

600 lines
12 KiB
ArmAsm

; rotozoomer!
; with 16x16 texture
; takes a lores-formatted image in $c00 and rotozooms it
; by ANGLE and SCALE_I/SCALE_F and draws it to the
; lo-res page in DRAW_PAGE
; ANGLE in our case is 0..31
; SCALE_I/SCALE_F is 8.8 fixed point scale multiplier
; $2E7CF = 190,415 = 5.25fps first merging
; $2D8CF = 186,575 = 5.35fps move mask to rotate not draw
; $29CCF = 171,215 = 5.84fps do color conversion outside of loop
; $28DCF = 167,375 = 5.97fps two lookup tables for hi/low
; $26FCF = 159,695 = 6.26fps remove carry set/clear for fixed point adds
CAL = $B0
CAH = $B1
SAL = $B2
SAH = $B3
YPL = $B4
YPH = $B5
XPL = $B6
XPH = $B7
;YY
;XX
CCAL = $B8
CCAH = $B9
CSAL = $BA
CSAH = $BB
YCAL = $BC
YCAH = $BD
YSAL = $BE
YSAH = $BF
rotozoom:
; setup scale for multiply
lda SCALE_I ; 3
sta NUM1H ; 3
lda SCALE_F ; 3
sta NUM1L ; 3
; ca = cos(theta)*scale;
; (we use equiv ca=fixed_sin[(theta+8)&0xf] )
lda ANGLE ; 3
clc ; 2
adc #16 ; 2
and #$3f ; 2
asl ; 2
tay ; 2
lda fixed_sin,Y ; load integer half ; 4
sta NUM2H ; 3
lda fixed_sin+1,Y ; load float half ; 4
sta NUM2L ; 3
;===========
; 27
sec ; reload NUM1H/NUM1L ; 2
jsr multiply ; 6+???
stx CAH ; 3
sta CAL ; 3
; sa = sin(theta)*scale;
lda ANGLE ; 3
asl ; 2
tay ; 2
lda fixed_sin,Y ; load integer half ; 4
sta NUM2H ; 3
lda fixed_sin+1,Y ; load integer half ; 4
sta NUM2L ; 3
;==========
; 21
clc ; NUM1H/NUM1L same as last time ; 2
jsr multiply ; 6+???
stx SAH ; 3
sta SAL ; 3
; cca = -20*ca;
lda #<(-20) ; 2
sta NUM1H ; 3
lda #0 ; 2
sta NUM1L ; 3
lda CAL ; 3
sta NUM2L ; 3
lda CAH ; 3
sta NUM2H ; 3
sec ; reload NUM1H/NUM1L ; 2
jsr multiply ; 6+???
stx CCAH ; 3
sta CCAL ; 3
; csa = -20*sa;
lda SAL ; 3
sta NUM2L ; 3
lda SAH ; 3
sta NUM2H ; 3
clc ; same NUM1H/NUM1L as las time ; 2
jsr multiply ; 6+???
stx CSAH ; 3
sta CSAL ; 3
; yca=cca+ycenter;
lda CCAL ; 3
sta YCAL ; 3
clc ; 2
lda CCAH ; 3
adc #20 ; 2
sta YCAH ; 3
;===========
; 16
; ysa=csa+xcenter;
lda CSAL ; 3
sta YSAL ; 3
clc ; 2
lda CSAH ; 3
adc #20 ; 2
sta YSAH ; 3
;===========
; 16
; yloop, unrolled once
;===================================================================
; for(yy=0;yy<40;yy++) {
;===================================================================
ldy #0 ; 2
sty YY ; 3
rotozoom_yloop:
; setup self-modifying code for plot
; YY already in Y from end of loop
; ldy YY ; 3
lda common_offsets_l,Y ; lookup low-res memory address ; 4
sta rplot2_smc+1 ; 4
sta rplot12_smc+1 ; 4
sta rplot22_smc+1 ; 4
clc ; 2
lda gr_400_offsets_h,Y ; 4
adc DRAW_PAGE ; add in draw page offset ; 3
sta rplot2_smc+2 ; 4
sta rplot12_smc+2 ; 4
sta rplot22_smc+2 ; 4
;=====================
; unroll 0, even line
;=====================
; xp=cca+ysa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
adc CCAL ; 3
sta XPL ; 3
lda YSAH ; 3
adc CCAH ; 3
sta XPH ; 3
;==========
; 20
; yp=yca-csa; 8.8 fixed point
sec ; 2
lda YCAL ; 3
sbc CSAL ; 3
sta YPL ; 3
lda YCAH ; 3
sbc CSAH ; 3
sta YPH ; 3
;===========
; 20
; for(xx=0;xx<40;xx++) {
ldx #0 ; 2
rotozoom_xloop:
;===================================================================
;===================================================================
; note: every cycle saved below here
; saves 1600 cycles
;===================================================================
;===================================================================
lda XPH ; 3
and #$f ; 2
sta CTEMP ; 3
lda YPH ; 3
asl ; 2
asl ; 2
asl ; 2
asl ; 2
clc ; 2
adc CTEMP ; 3
tay ; 2
lda low_lookup,Y ; 4
;============
; 30
rscrn_done:
;=============================================
; always even, want A in bottom of nibble
; so we are all set
rotozoom_set_color:
; want same color in top and bottom nibbles
;==========
; 0
;=================================================
rplot:
; plot(xx,yy); (color is in A)
; we are in loop unroll0 so always even line here
; meaning we want to load old color, save top nibble, and over-write
; bottom nibble with our value
; but! we don't need to save old as we are re-drawing whole screen!
rplot_even:
rplot2_smc:
sta $400,X ; 5
;============
; 5
;=======================
; xp=xp+ca; fixed point 8.8
; always set? also low importance LSB
; clc ; 2
lda CAL ; 3
adc XPL ; 3
sta XPL ; 3
lda CAH ; 3
adc XPH ; 3
sta XPH ; 3
; yp=yp-sa; fixed point 8.8
; low importance LSB?
; sec ; 2
lda YPL ; 3
sbc SAL ; 3
sta YPL ; 3
lda YPH ; 3
sbc SAH ; 3
sta YPH ; 3
rotozoom_end_xloop:
inx ; 2
cpx #40 ; 2
bne rotozoom_xloop ; 2nt/3
rotozoom_xloop_done:
; yca+=ca; 8.8 fixed point
clc ; 2
lda YCAL ; 3
adc CAL ; 3
sta YCAL ; 3
lda YCAH ; 3
adc CAH ; 3
sta YCAH ; 3
;===========
; 20
; ysa+=sa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
adc SAL ; 3
sta YSAL ; 3
lda YSAH ; 3
adc SAH ; 3
sta YSAH ; 3
;==========
; 20
;===============
; loop unroll 1
;===============
;rotozoom_yloop:
; xp=cca+ysa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
adc CCAL ; 3
sta XPL ; 3
lda YSAH ; 3
adc CCAH ; 3
sta XPH ; 3
;==========
; 20
; yp=yca-csa; 8.8 fixed point
sec ; 2
lda YCAL ; 3
sbc CSAL ; 3
sta YPL ; 3
lda YCAH ; 3
sbc CSAH ; 3
sta YPH ; 3
;===========
; 20
; for(xx=0;xx<40;xx++) {
ldx #0 ; 2
rotozoom_xloop2:
;===================================================================
;===================================================================
; note: every cycle saved below here
; saves 1600 cycles
;===================================================================
;===================================================================
; if ((xp<0) || (xp>39)) color=0;
; else if ((yp<0) || (yp>39)) color=0;
; else color=scrn_page(xp,yp,PAGE2);
; we know it's never going to go *that* far out of bounds
; so we could avoid the Y check by just having "0"
; on the edges of the screen? Tricky due to Apple II
; interlacing
lda XPH
and #$f
sta CTEMP
lda YPH
asl
asl
asl
asl
clc
adc CTEMP
tay
lda high_lookup,Y
; and #$f0
;=============================================
rotozoom_set_color2:
; always odd
; want color in top, which it is from above
;==========
; 0
;=================================================
rplot2:
; plot(xx,yy); (color is in A)
; always odd, so place color in top
; note! since we are drawing whole screen, we know the top of
; the value is already clear from loop=0 so we don't have to mask
rplot_odd:
rplot12_smc:
ora $400,X ; 4
rplot22_smc:
sta $400,X ; 5
;============
; 9
;=======================
; xp=xp+ca; 8.8 fixed point
; clc ; 2
lda CAL ; 3
adc XPL ; 3
sta XPL ; 3
lda CAH ; 3
adc XPH ; 3
sta XPH ; 3
; yp=yp-sa; 8.8 fixed point
; sec ; 2
lda YPL ; 3
sbc SAL ; 3
sta YPL ; 3
lda YPH ; 3
sbc SAH ; 3
sta YPH ; 3
rotozoom_end_xloop2:
inx ; 2
cpx #40 ; 2
bne rotozoom_xloop2 ; 3
rotozoom_xloop_done2:
; yca+=ca; 8.8 fixed point
clc ; 2
lda YCAL ; 3
adc CAL ; 3
sta YCAL ; 3
lda YCAH ; 3
adc CAH ; 3
sta YCAH ; 3
;===========
; 20
; ysa+=sa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
adc SAL ; 3
sta YSAL ; 3
lda YSAH ; 3
adc SAH ; 3
sta YSAH ; 3
;==========
; 20
rotozoom_end_yloop:
inc YY ; 5
ldy YY ; 3
cpy #24 ; 2
beq done_rotozoom ; 2nt/3
jmp rotozoom_yloop ; too far ; 3
done_rotozoom:
rts ; 6
fixed_sin:
; .byte $00,$00 ; 0.000000=00.00
; .byte $00,$61 ; 0.382683=00.61
; .byte $00,$b5 ; 0.707107=00.b5
; .byte $00,$ec ; 0.923880=00.ec
; .byte $01,$00 ; 1.000000=01.00
; .byte $00,$ec ; 0.923880=00.ec
; .byte $00,$b5 ; 0.707107=00.b5
; .byte $00,$61 ; 0.382683=00.61
; .byte $00,$00 ; 0.000000=00.00
; .byte $ff,$9f ; -0.382683=ff.9f
; .byte $ff,$4b ; -0.707107=ff.4b
; .byte $ff,$14 ; -0.923880=ff.14
; .byte $ff,$00 ; -1.000000=ff.00
; .byte $ff,$14 ; -0.923880=ff.14
; .byte $ff,$4b ; -0.707107=ff.4b
; .byte $ff,$9f ; -0.382683=ff.9f
.if 0
.byte $00,$00 ; 0.000000
.byte $00,$31 ; 0.195090
.byte $00,$61 ; 0.382683
.byte $00,$8E ; 0.555570
.byte $00,$B5 ; 0.707107
.byte $00,$D4 ; 0.831470
.byte $00,$EC ; 0.923880
.byte $00,$FB ; 0.980785
.byte $01,$00 ; 1.000000
.byte $00,$FB ; 0.980785
.byte $00,$EC ; 0.923880
.byte $00,$D4 ; 0.831470
.byte $00,$B5 ; 0.707107
.byte $00,$8E ; 0.555570
.byte $00,$61 ; 0.382683
.byte $00,$31 ; 0.195090
.byte $00,$00 ; 0.000000
.byte $FF,$CF ; -0.195090
.byte $FF,$9F ; -0.382683
.byte $FF,$72 ; -0.555570
.byte $FF,$4B ; -0.707107
.byte $FF,$2C ; -0.831470
.byte $FF,$14 ; -0.923880
.byte $FF,$05 ; -0.980785
.byte $FF,$00 ; -1.000000
.byte $FF,$05 ; -0.980785
.byte $FF,$14 ; -0.923880
.byte $FF,$2C ; -0.831470
.byte $FF,$4B ; -0.707107
.byte $FF,$72 ; -0.555570
.byte $FF,$9F ; -0.382683
.byte $FF,$CF ; -0.195090
.endif
.byte $00,$00 ; 0.000000
.byte $00,$19 ; 0.098017
.byte $00,$31 ; 0.195090
.byte $00,$4A ; 0.290285
.byte $00,$61 ; 0.382683
.byte $00,$78 ; 0.471397
.byte $00,$8E ; 0.555570
.byte $00,$A2 ; 0.634393
.byte $00,$B5 ; 0.707107
.byte $00,$C5 ; 0.773010
.byte $00,$D4 ; 0.831470
.byte $00,$E1 ; 0.881921
.byte $00,$EC ; 0.923880
.byte $00,$F4 ; 0.956940
.byte $00,$FB ; 0.980785
.byte $00,$FE ; 0.995185
.byte $01,$00 ; 1.000000
.byte $00,$FE ; 0.995185
.byte $00,$FB ; 0.980785
.byte $00,$F4 ; 0.956940
.byte $00,$EC ; 0.923880
.byte $00,$E1 ; 0.881921
.byte $00,$D4 ; 0.831470
.byte $00,$C5 ; 0.773010
.byte $00,$B5 ; 0.707107
.byte $00,$A2 ; 0.634393
.byte $00,$8E ; 0.555570
.byte $00,$78 ; 0.471397
.byte $00,$61 ; 0.382683
.byte $00,$4A ; 0.290285
.byte $00,$31 ; 0.195090
.byte $00,$19 ; 0.098017
.byte $00,$00 ; 0.000000
.byte $FF,$E7 ; -0.098017
.byte $FF,$CF ; -0.195090
.byte $FF,$B6 ; -0.290285
.byte $FF,$9F ; -0.382683
.byte $FF,$88 ; -0.471397
.byte $FF,$72 ; -0.555570
.byte $FF,$5E ; -0.634393
.byte $FF,$4B ; -0.707107
.byte $FF,$3B ; -0.773010
.byte $FF,$2C ; -0.831470
.byte $FF,$1F ; -0.881921
.byte $FF,$14 ; -0.923880
.byte $FF,$0C ; -0.956940
.byte $FF,$05 ; -0.980785
.byte $FF,$02 ; -0.995185
.byte $FF,$00 ; -1.000000
.byte $FF,$02 ; -0.995185
.byte $FF,$05 ; -0.980785
.byte $FF,$0C ; -0.956940
.byte $FF,$14 ; -0.923880
.byte $FF,$1F ; -0.881921
.byte $FF,$2C ; -0.831470
.byte $FF,$3B ; -0.773010
.byte $FF,$4B ; -0.707107
.byte $FF,$5E ; -0.634393
.byte $FF,$72 ; -0.555570
.byte $FF,$88 ; -0.471397
.byte $FF,$9F ; -0.382683
.byte $FF,$B6 ; -0.290285
.byte $FF,$CF ; -0.195090
.byte $FF,$E7 ; -0.098017