rotozoom: optimized the unrolled loop

This commit is contained in:
Vince Weaver 2021-01-07 15:14:51 -05:00
parent 9e68cd70f5
commit 97f20e3c0c

View File

@ -14,6 +14,7 @@
; $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
; $2BA83=178,819=5.59fps optimize unrolled loop
CAL = $B0
CAH = $B1
@ -143,16 +144,16 @@ rotozoom:
; for(yy=0;yy<40;yy++) {
;===================================================================
lda #0 ; 2
sta YY ; 3
ldy #0 ; 2
sty YY ; 3
rotozoom_yloop:
; setup self-modifying code for plot
ldy YY ; 3
; YY already in Y from end of loop
; ldy YY ; 3
lda common_offsets_l,Y ; lookup low-res memory address ; 4
sta rplot1_smc+1 ; 4
sta rplot2_smc+1 ; 4
sta rplot12_smc+1 ; 4
sta rplot22_smc+1 ; 4
@ -160,7 +161,6 @@ rotozoom_yloop:
clc ; 2
lda gr_400_offsets_h,Y ; 4
adc DRAW_PAGE ; add in draw page offset ; 3
sta rplot1_smc+2 ; 4
sta rplot2_smc+2 ; 4
sta rplot12_smc+2 ; 4
sta rplot22_smc+2 ; 4
@ -172,7 +172,7 @@ rotozoom_yloop:
;=====================
; xp=cca+ysa;
; xp=cca+ysa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
adc CCAL ; 3
@ -183,7 +183,7 @@ rotozoom_yloop:
;==========
; 20
; yp=yca-csa;
; yp=yca-csa; 8.8 fixed point
sec ; 2
lda YCAL ; 3
@ -257,15 +257,16 @@ rotozoom_xloop:
; carry was set a bit before to low bit of YPH
; hopefully nothing has cleared it
bcs rscrn_adjust_odd ; 3
bcs rscrn_adjust_odd ; 2nt/3
rscrn_adjust_even:
; want bottom
; YP was even so want bottom nibble
and #$f ; 2
jmp rscrn_done ; 3
rscrn_adjust_odd:
; YP was odd so want top nibble
lsr ; 2
lsr ; 2
lsr ; 2
@ -279,12 +280,12 @@ 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
and #$f
;==========
; 8
; 0
;=================================================
@ -292,22 +293,23 @@ rplot:
; plot(xx,yy); (color is in A)
; we are in loop unroll0 so always even line here
; always even line here
; meaning we want to load old color, save top nibble, and over-write
; bottom nibble with our value
; but! we don't need to save old as we are re-drawing whole screen!
rplot_even:
sta COLOR ; 3
lda #$f0 ; 2
rplot1_smc:
and $400,X ; 4
ora COLOR ; 3
rplot2_smc:
sta $400,X ; 5
;============
; 5
;=======================
; xp=xp+ca;
; xp=xp+ca; fixed point 8.8
clc ; 2
lda CAL ; 3
@ -317,7 +319,7 @@ rplot2_smc:
adc XPH ; 3
sta XPH ; 3
; yp=yp-sa;
; yp=yp-sa; fixed point 8.8
sec ; 2
lda YPL ; 3
@ -330,13 +332,12 @@ rplot2_smc:
rotozoom_end_xloop:
inx ; 2
cpx #40 ; 2
beq rotozoom_xloop_done ; 2nt/3
jmp rotozoom_xloop ; 3
bne rotozoom_xloop ; 2nt/3
rotozoom_xloop_done:
; yca+=ca;
; yca+=ca; 8.8 fixed point
clc ; 2
lda YCAL ; 3
@ -348,7 +349,7 @@ rotozoom_xloop_done:
;===========
; 20
; ysa+=sa;
; ysa+=sa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
@ -367,7 +368,7 @@ rotozoom_xloop_done:
;rotozoom_yloop:
; xp=cca+ysa;
; xp=cca+ysa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
adc CCAL ; 3
@ -378,7 +379,7 @@ rotozoom_xloop_done:
;==========
; 20
; yp=yca-csa;
; yp=yca-csa; 8.8 fixed point
sec ; 2
lda YCAL ; 3
@ -454,15 +455,18 @@ rotozoom_xloop2:
rscrn_adjust_even2:
; want bottom
and #$f ; 2
; want bottom color, but put it in top of A
asl ; 2
asl ; 2
asl ; 2
asl ; 2
jmp rscrn_done2 ; 3
rscrn_adjust_odd2:
lsr ; 2
lsr ; 2
lsr ; 2
lsr ; 2
; want top color alone
and #$f0 ; 2
rscrn_done2:
@ -473,13 +477,9 @@ rscrn_done2:
rotozoom_set_color2:
; always odd
; want color in top
asl ; 2
asl ; 2
asl ; 2
asl ; 2
; want color in top, which it is from above
;==========
; 8
; 0
;=================================================
@ -487,21 +487,23 @@ rplot2:
; plot(xx,yy); (color is in A)
; always odd
; 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:
sta COLOR ; 3
lda #$0f ; 2
rplot12_smc:
and $400,X ; 4
ora COLOR ; 3
ora $400,X ; 4
rplot22_smc:
sta $400,X ; 5
;============
; 9
;=======================
; xp=xp+ca;
; xp=xp+ca; 8.8 fixed point
clc ; 2
lda CAL ; 3
@ -511,7 +513,7 @@ rplot22_smc:
adc XPH ; 3
sta XPH ; 3
; yp=yp-sa;
; yp=yp-sa; 8.8 fixed point
sec ; 2
lda YPL ; 3
@ -524,11 +526,10 @@ rplot22_smc:
rotozoom_end_xloop2:
inx ; 2
cpx #40 ; 2
beq rotozoom_xloop_done2 ; 2nt/3
jmp rotozoom_xloop2 ; 3
bne rotozoom_xloop2 ; 3
rotozoom_xloop_done2:
; yca+=ca;
; yca+=ca; 8.8 fixed point
clc ; 2
lda YCAL ; 3
@ -540,7 +541,7 @@ rotozoom_xloop_done2:
;===========
; 20
; ysa+=sa;
; ysa+=sa; 8.8 fixed point
clc ; 2
lda YSAL ; 3
@ -554,8 +555,8 @@ rotozoom_xloop_done2:
rotozoom_end_yloop:
inc YY ; 5
lda YY ; 3
cmp #20 ; 2
ldy YY ; 3
cpy #20 ; 2
beq done_rotozoom ; 2nt/3
jmp rotozoom_yloop ; too far ; 3