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dos33fsprogs
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rotozoom: unroll loop 

decent performance increase
This commit is contained in:
Vince Weaver 2021-01-07 14:38:18 -05:00
parent 74ea0a13b9
commit 9e68cd70f5
1 changed files with 241 additions and 52 deletions
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293
graphics/gr/rotozoom/rotozoom.s
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@ -13,7 +13,7 @@
; $39fdf=237,535 add two scale multiplies
; $39e17=237,079=4.22fps change the init to also use multiply
; $39dc9=237,001= change to use common lookup table (outside inner loop)
; $3399f=211,359=4.73fps unroll the Y loop by one
CAL = $B0
CAH = $B1
@ -138,12 +138,40 @@ rotozoom:
;===========
; 16
; yloop, unrolled once
;===================================================================
; for(yy=0;yy<40;yy++) {
;===================================================================
lda #0 ; 2
sta YY ; 3
rotozoom_yloop:
; setup self-modifying code for plot
ldy YY ; 3
lda common_offsets_l,Y ; lookup low-res memory address ; 4
sta rplot1_smc+1 ; 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 rplot1_smc+2 ; 4
sta rplot2_smc+2 ; 4
sta rplot12_smc+2 ; 4
sta rplot22_smc+2 ; 4
;=====================
; unroll 0, even line
;=====================
; xp=cca+ysa;
clc ; 2
lda YSAL ; 3
@ -168,38 +196,19 @@ rotozoom_yloop:
; 20
; setup self-modifying code for plot
lda YY ; 3
lsr ; get low bit in carry ; 2
bcc smc_even ; 2nt/3
smc_odd:
ldy #$2c ; bit ; 2
jmp smc_write ; 3
smc_even:
ldy #$4c ; jmp ; 2
smc_write:
sty rplot3_smc ; 4
tay ; 2
lda common_offsets_l,Y ; lookup low-res memory address ; 4
sta rplot1_smc+1 ; 4
sta rplot2_smc+1 ; 4
clc ; 2
lda gr_400_offsets_h,Y ; 4
adc DRAW_PAGE ; add in draw page offset ; 3
sta rplot1_smc+2 ; 4
sta rplot2_smc+2 ; 4
; for(xx=0;xx<40;xx++) {
ldx #0 ; 2
rotozoom_xloop:
;==========================
;===================================================================
;===================================================================
; note: every cycle saved below here
; saves 1600 cycles
;==========================
;===================================================================
;===================================================================
; if ((xp<0) || (xp>39)) color=0;
; else if ((yp<0) || (yp>39)) color=0;
@ -241,23 +250,22 @@ rotozoom_xloop:
lda scrn_c00_offsets_h,Y ; 4
sta BASH ; 3
ldy XPH ; 3
lda (BASL),Y ; top/bottom color ; 5+
; carry was set a bit before to low bit of YPH
; hopefully nothing has cleared it
bcs rscrn_adjust_odd ; 3
rscrn_adjust_even:
ldy XPH ; 3
; want bottom
lda (BASL),Y ; top/bottom color ; 5+
and #$f ; 2
jmp rscrn_done ; 3
rscrn_adjust_odd:
ldy XPH ; 3
; want top
lda (BASL),Y ; top/bottom color ; 5+
lsr ; 2
lsr ; 2
lsr ; 2
@ -270,16 +278,13 @@ rscrn_done:
;=============================================
; always even, want A in bottom of nibble
rotozoom_set_color:
; want same color in top and bottom nibbles
sta TEMP ; 3
asl ; 2
asl ; 2
asl ; 2
asl ; 2
ora TEMP ; 3
and #$f
;==========
; 14
; 8
;=================================================
@ -287,21 +292,12 @@ rplot:
; plot(xx,yy); (color is in A)
; smc based on if Y is odd or even
rplot3_smc:
jmp rplot_even ; 3
rplot_odd:
and #$f0 ; 2
sta COLOR ; 3
lda #$0f ; 2
bne rplot1_smc ; bra ; 3
; always even line here
rplot_even:
and #$0f ; 2
sta COLOR ; 3
lda #$f0 ; 2
rplot1_smc:
and $400,X ; 4
ora COLOR ; 3
@ -331,7 +327,6 @@ rplot2_smc:
sbc SAH ; 3
sta YPH ; 3
rotozoom_end_xloop:
inx ; 2
cpx #40 ; 2
@ -339,6 +334,200 @@ rotozoom_end_xloop:
jmp rotozoom_xloop ; 3
rotozoom_xloop_done:
; yca+=ca;
clc ; 2
lda YCAL ; 3
adc CAL ; 3
sta YCAL ; 3
lda YCAH ; 3
adc CAH ; 3
sta YCAH ; 3
;===========
; 20
; ysa+=sa;
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;
clc ; 2
lda YSAL ; 3
adc CCAL ; 3
sta XPL ; 3
lda YSAH ; 3
adc CCAH ; 3
sta XPH ; 3
;==========
; 20
; yp=yca-csa;
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 #0 ; default color ; 2
ldy XPH ; 3
bmi rplot2 ; 2nt/3
cpy #40 ; 2
bcs rplot2 ; 2nt/3
ldy YPH ; 3
bmi rplot2 ; 2nt/3
cpy #40 ; 2
bcs rplot2 ; 2nt/3
;==================================================
; scrn(xp,yp)
tya ; YPH ; 2
lsr ; divide to get index, also low bit in carry ; 2
tay ; 2
; TODO: put these in zero page?
; also we can share low bytes with other lookup
lda common_offsets_l,Y ; lookup low-res memory address ; 4
sta BASL ; 3
lda scrn_c00_offsets_h,Y ; 4
sta BASH ; 3
ldy XPH ; 3
lda (BASL),Y ; top/bottom color ; 5+
; carry was set a bit before to low bit of YPH
; hopefully nothing has cleared it
bcs rscrn_adjust_odd2 ; 3
rscrn_adjust_even2:
; want bottom
and #$f ; 2
jmp rscrn_done2 ; 3
rscrn_adjust_odd2:
lsr ; 2
lsr ; 2
lsr ; 2
lsr ; 2
rscrn_done2:
;=============================================
rotozoom_set_color2:
; always odd
; want color in top
asl ; 2
asl ; 2
asl ; 2
asl ; 2
;==========
; 8
;=================================================
rplot2:
; plot(xx,yy); (color is in A)
; always odd
rplot_odd:
sta COLOR ; 3
lda #$0f ; 2
rplot12_smc:
and $400,X ; 4
ora COLOR ; 3
rplot22_smc:
sta $400,X ; 5
;=======================
; xp=xp+ca;
clc ; 2
lda CAL ; 3
adc XPL ; 3
sta XPL ; 3
lda CAH ; 3
adc XPH ; 3
sta XPH ; 3
; yp=yp-sa;
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
beq rotozoom_xloop_done2 ; 2nt/3
jmp rotozoom_xloop2 ; 3
rotozoom_xloop_done2:
; yca+=ca;
clc ; 2
@ -366,7 +555,7 @@ rotozoom_xloop_done:
rotozoom_end_yloop:
inc YY ; 5
lda YY ; 3
cmp #40 ; 2
cmp #20 ; 2
beq done_rotozoom ; 2nt/3
jmp rotozoom_yloop ; too far ; 3