627 lines
12 KiB
ArmAsm
627 lines
12 KiB
ArmAsm
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; rotozoomer!
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; takes a lores-formatted image in $c00 and rotozooms it
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; by ANGLE and SCALE_I/SCALE_F and draws it to the
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; lo-res page in DRAW_PAGE
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; ANGLE in our case is 0..31
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; SCALE_I/SCALE_F is 8.8 fixed point scale multiplier
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; optimization (cycles measured at ANGLE=0)
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; $6BD76=441,718=2.26fps initial code with external plot and scrn
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; $62776=403,318=2.48fps inline plot
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; $597b6=366,518=2.73fps inline scrn
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; $4F496=324,758=3.08fps move plot line calc outside of inner loop
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; $49d16=302,358=3.31fps do color*17 ourselves
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; $4645e=287,838=3.47fps move XX into X
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; $3ef7e=257,918=3.87fps optimize plot
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; $3c9fe=248,318=4.03fps optimize scrn
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; $39e3e=237,118=4.22fps add scrn address lookup table
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; $39fdf=237,535 add two scale multiplies
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; $39e17=237,079=4.22fps change the init to also use multiply
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; $39dc9=237,001= change to use common lookup table (outside inner loop)
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; $3399f=211,359=4.73fps unroll the Y loop by one
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; $2BA83=178,819=5.59fps optimize unrolled loop
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; $2B14B=176,459=5.66fps avoid extra jump (qkumba)
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CAL = $C0
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CAH = $C1
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SAL = $C2
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SAH = $C3
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YPL = $C4
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YPH = $C5
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XPL = $C6
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XPH = $C7
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CCAL = $C8
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CCAH = $C9
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CSAL = $CA
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CSAH = $CB
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YCAL = $CC
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YCAH = $CD
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YSAL = $CE
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YSAH = $CF
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rotozoom:
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; setup scale for multiply
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lda SCALE_I ; 3
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sta NUM1H ; 3
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lda SCALE_F ; 3
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sta NUM1L ; 3
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; ca = cos(theta)*scale;
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; (we use equiv ca=fixed_sin[(theta+8)&0xf] )
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lda ANGLE ; 3
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clc ; 2
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adc #8 ; 2
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and #$1f ; 2
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asl ; 2
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tay ; 2
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lda fixed_sin,Y ; load integer half ; 4
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sta NUM2H ; 3
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lda fixed_sin+1,Y ; load float half ; 4
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sta NUM2L ; 3
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;===========
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; 27
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sec ; reload NUM1H/NUM1L ; 2
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jsr multiply ; 6+???
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stx CAH ; 3
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sta CAL ; 3
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; sa = sin(theta)*scale;
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lda ANGLE ; 3
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asl ; 2
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tay ; 2
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lda fixed_sin,Y ; load integer half ; 4
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sta NUM2H ; 3
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lda fixed_sin+1,Y ; load integer half ; 4
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sta NUM2L ; 3
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;==========
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; 21
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clc ; NUM1H/NUM1L same as last time ; 2
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jsr multiply ; 6+???
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stx SAH ; 3
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sta SAL ; 3
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; cca = -20*ca;
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lda #<(-20) ; 2
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sta NUM1H ; 3
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lda #0 ; 2
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sta NUM1L ; 3
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lda CAL ; 3
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sta NUM2L ; 3
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lda CAH ; 3
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sta NUM2H ; 3
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sec ; reload NUM1H/NUM1L ; 2
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jsr multiply ; 6+???
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stx CCAH ; 3
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sta CCAL ; 3
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; csa = -20*sa;
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lda SAL ; 3
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sta NUM2L ; 3
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lda SAH ; 3
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sta NUM2H ; 3
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clc ; same NUM1H/NUM1L as las time ; 2
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jsr multiply ; 6+???
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stx CSAH ; 3
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sta CSAL ; 3
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; yca=cca+ycenter;
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lda CCAL ; 3
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sta YCAL ; 3
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clc ; 2
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lda CCAH ; 3
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adc #20 ; 2
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sta YCAH ; 3
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;===========
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; 16
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; ysa=csa+xcenter;
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lda CSAL ; 3
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sta YSAL ; 3
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clc ; 2
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lda CSAH ; 3
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adc #20 ; 2
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sta YSAH ; 3
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;===========
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; 16
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; yloop, unrolled once
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;===================================================================
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; for(yy=0;yy<40;yy++) {
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;===================================================================
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ldy #0 ; 2
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sty YY ; 3
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rotozoom_yloop:
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; setup self-modifying code for plot
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; YY already in Y from end of loop
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; ldy YY ; 3
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lda common_offsets_l,Y ; lookup low-res memory address ; 4
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sta rplot2_smc+1 ; 4
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sta rplot12_smc+1 ; 4
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sta rplot22_smc+1 ; 4
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clc ; 2
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lda gr_400_offsets_h,Y ; 4
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adc DRAW_PAGE ; add in draw page offset ; 3
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sta rplot2_smc+2 ; 4
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sta rplot12_smc+2 ; 4
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sta rplot22_smc+2 ; 4
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;=====================
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; unroll 0, even line
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;=====================
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; xp=cca+ysa; 8.8 fixed point
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clc ; 2
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lda YSAL ; 3
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adc CCAL ; 3
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sta XPL ; 3
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lda YSAH ; 3
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adc CCAH ; 3
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sta XPH ; 3
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;==========
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; 20
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; yp=yca-csa; 8.8 fixed point
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sec ; 2
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lda YCAL ; 3
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sbc CSAL ; 3
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sta YPL ; 3
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lda YCAH ; 3
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sbc CSAH ; 3
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sta YPH ; 3
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;===========
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; 20
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; for(xx=0;xx<40;xx++) {
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ldx #0 ; 2
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rotozoom_xloop:
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;===================================================================
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;===================================================================
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; note: every cycle saved below here
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; saves 1600 cycles
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;===================================================================
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;===================================================================
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; if ((xp<0) || (xp>39)) color=0;
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; else if ((yp<0) || (yp>39)) color=0;
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; else color=scrn_page(xp,yp,PAGE2);
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; we know it's never going to go *that* far out of bounds
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; so we could avoid the Y check by just having "0"
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; on the edges of the screen? Tricky due to Apple II
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; interlacing
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roto_color_even_smc:
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lda #0 ; default color ; 2
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ldy XPH ; 3
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bmi rplot ; 2nt/3
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cpy #40 ; 2
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bcs rplot ; 2nt/3
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ldy YPH ; 3
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bmi rplot ; 2nt/3
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cpy #40 ; 2
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bcs rplot ; 2nt/3
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;==================================================
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; scrn(xp,yp)
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tya ; YPH ; 2
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lsr ; divide to get index, also low bit in carry ; 2
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tay ; 2
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; TODO: put these in zero page?
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; also we can share low bytes with other lookup
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lda common_offsets_l,Y ; lookup low-res memory address ; 4
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sta BASL ; 3
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lda scrn_c00_offsets_h,Y ; 4
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sta BASH ; 3
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ldy XPH ; 3
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lda (BASL),Y ; top/bottom color ; 5+
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; carry was set a bit before to low bit of YPH
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; hopefully nothing has cleared it
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bcc rscrn_adjust_even ; 2nt/3
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rscrn_adjust_odd:
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; YP was odd so want top nibble
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lsr ; 2
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lsr ; 2
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lsr ; 2
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lsr ; 2
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; fall through
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rscrn_adjust_even:
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; YP was even so want bottom nibble
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and #$f ; 2
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rscrn_done:
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;=============================================
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; always even, want A in bottom of nibble
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; so we are all set
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rotozoom_set_color:
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; want same color in top and bottom nibbles
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;==========
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; 0
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;=================================================
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rplot:
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; plot(xx,yy); (color is in A)
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; we are in loop unroll0 so always even line here
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; meaning we want to load old color, save top nibble, and over-write
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; bottom nibble with our value
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; but! we don't need to save old as we are re-drawing whole screen!
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rplot_even:
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rplot2_smc:
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sta $400,X ; 5
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;============
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; 5
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;=======================
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; xp=xp+ca; fixed point 8.8
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clc ; 2
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lda CAL ; 3
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adc XPL ; 3
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sta XPL ; 3
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lda CAH ; 3
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adc XPH ; 3
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sta XPH ; 3
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; yp=yp-sa; fixed point 8.8
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sec ; 2
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lda YPL ; 3
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sbc SAL ; 3
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sta YPL ; 3
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lda YPH ; 3
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sbc SAH ; 3
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sta YPH ; 3
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rotozoom_end_xloop:
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inx ; 2
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cpx #40 ; 2
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bne rotozoom_xloop ; 2nt/3
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rotozoom_xloop_done:
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; yca+=ca; 8.8 fixed point
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clc ; 2
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lda YCAL ; 3
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adc CAL ; 3
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sta YCAL ; 3
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lda YCAH ; 3
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adc CAH ; 3
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sta YCAH ; 3
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;===========
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; 20
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; ysa+=sa; 8.8 fixed point
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clc ; 2
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lda YSAL ; 3
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adc SAL ; 3
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sta YSAL ; 3
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lda YSAH ; 3
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adc SAH ; 3
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sta YSAH ; 3
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;==========
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; 20
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;===============
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; loop unroll 1
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;===============
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;rotozoom_yloop:
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; xp=cca+ysa; 8.8 fixed point
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clc ; 2
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lda YSAL ; 3
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adc CCAL ; 3
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sta XPL ; 3
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lda YSAH ; 3
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adc CCAH ; 3
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sta XPH ; 3
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;==========
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; 20
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; yp=yca-csa; 8.8 fixed point
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sec ; 2
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lda YCAL ; 3
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sbc CSAL ; 3
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sta YPL ; 3
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lda YCAH ; 3
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sbc CSAH ; 3
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sta YPH ; 3
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;===========
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; 20
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; for(xx=0;xx<40;xx++) {
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ldx #0 ; 2
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rotozoom_xloop2:
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;===================================================================
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;===================================================================
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; note: every cycle saved below here
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; saves 1600 cycles
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;===================================================================
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;===================================================================
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; if ((xp<0) || (xp>39)) color=0;
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; else if ((yp<0) || (yp>39)) color=0;
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; else color=scrn_page(xp,yp,PAGE2);
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; we know it's never going to go *that* far out of bounds
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; so we could avoid the Y check by just having "0"
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; on the edges of the screen? Tricky due to Apple II
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; interlacing
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roto_color_odd_smc:
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lda #0 ; default color ; 2
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ldy XPH ; 3
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bmi rplot2 ; 2nt/3
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cpy #40 ; 2
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bcs rplot2 ; 2nt/3
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ldy YPH ; 3
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bmi rplot2 ; 2nt/3
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cpy #40 ; 2
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bcs rplot2 ; 2nt/3
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;==================================================
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; scrn(xp,yp)
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tya ; YPH ; 2
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lsr ; divide to get index, also low bit in carry ; 2
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tay ; 2
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; TODO: put these in zero page?
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; also we can share low bytes with other lookup
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lda common_offsets_l,Y ; lookup low-res memory address ; 4
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sta BASL ; 3
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lda scrn_c00_offsets_h,Y ; 4
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sta BASH ; 3
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ldy XPH ; 3
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lda (BASL),Y ; top/bottom color ; 5+
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; carry was set a bit before to low bit of YPH
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; hopefully nothing has cleared it
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bcs rscrn_adjust_odd2 ; 3
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rscrn_adjust_even2:
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; want bottom color, but put it in top of A
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asl ; 2
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asl ; 2
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asl ; 2
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asl ; 2
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jmp rscrn_done2 ; 3
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rscrn_adjust_odd2:
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; want top color alone
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and #$f0 ; 2
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rscrn_done2:
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;=============================================
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rotozoom_set_color2:
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; always odd
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; want color in top, which it is from above
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;==========
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; 0
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;=================================================
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rplot2:
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; plot(xx,yy); (color is in A)
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; always odd, so place color in top
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; note! since we are drawing whole screen, we know the top of
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; the value is already clear from loop=0 so we don't have to mask
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rplot_odd:
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rplot12_smc:
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ora $400,X ; 4
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rplot22_smc:
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sta $400,X ; 5
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;============
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; 9
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;=======================
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; xp=xp+ca; 8.8 fixed point
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clc ; 2
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lda CAL ; 3
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adc XPL ; 3
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sta XPL ; 3
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lda CAH ; 3
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adc XPH ; 3
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sta XPH ; 3
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; yp=yp-sa; 8.8 fixed point
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sec ; 2
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lda YPL ; 3
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sbc SAL ; 3
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sta YPL ; 3
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lda YPH ; 3
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sbc SAH ; 3
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sta YPH ; 3
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rotozoom_end_xloop2:
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inx ; 2
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cpx #40 ; 2
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bne rotozoom_xloop2 ; 3
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rotozoom_xloop_done2:
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; yca+=ca; 8.8 fixed point
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clc ; 2
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lda YCAL ; 3
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adc CAL ; 3
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sta YCAL ; 3
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lda YCAH ; 3
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adc CAH ; 3
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sta YCAH ; 3
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;===========
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; 20
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; ysa+=sa; 8.8 fixed point
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clc ; 2
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lda YSAL ; 3
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adc SAL ; 3
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sta YSAL ; 3
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lda YSAH ; 3
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adc SAH ; 3
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sta YSAH ; 3
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;==========
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; 20
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rotozoom_end_yloop:
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inc YY ; 5
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ldy YY ; 3
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cpy #20 ; 2
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beq done_rotozoom ; 2nt/3
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jmp rotozoom_yloop ; too far ; 3
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done_rotozoom:
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rts ; 6
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fixed_sin:
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; .byte $00,$00 ; 0.000000=00.00
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; .byte $00,$61 ; 0.382683=00.61
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; .byte $00,$b5 ; 0.707107=00.b5
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; .byte $00,$ec ; 0.923880=00.ec
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; .byte $01,$00 ; 1.000000=01.00
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; .byte $00,$ec ; 0.923880=00.ec
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; .byte $00,$b5 ; 0.707107=00.b5
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; .byte $00,$61 ; 0.382683=00.61
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; .byte $00,$00 ; 0.000000=00.00
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; .byte $ff,$9f ; -0.382683=ff.9f
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; .byte $ff,$4b ; -0.707107=ff.4b
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; .byte $ff,$14 ; -0.923880=ff.14
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; .byte $ff,$00 ; -1.000000=ff.00
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; .byte $ff,$14 ; -0.923880=ff.14
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; .byte $ff,$4b ; -0.707107=ff.4b
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; .byte $ff,$9f ; -0.382683=ff.9f
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.byte $00,$00 ; 0.000000
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.byte $00,$31 ; 0.195090
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.byte $00,$61 ; 0.382683
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.byte $00,$8E ; 0.555570
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.byte $00,$B5 ; 0.707107
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.byte $00,$D4 ; 0.831470
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.byte $00,$EC ; 0.923880
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.byte $00,$FB ; 0.980785
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.byte $01,$00 ; 1.000000
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.byte $00,$FB ; 0.980785
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.byte $00,$EC ; 0.923880
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.byte $00,$D4 ; 0.831470
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.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
|