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entropy: add some comments

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This commit is contained in:
Vince Weaver 2018-05-28 00:22:47 -04:00
parent 07202ab93c
commit ed747e349f
1 changed files with 27 additions and 56 deletions
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83
two-liners/entropy.s
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@ -16,14 +16,6 @@
; Optimization
; 144 bytes: first working version (including DOS33 4-byte size/addr)
;BLT=BCC, BGE=BCS
; zero page locations
@ -70,38 +62,22 @@ TEN = $EA50
entropy:
loop:
jsr HGR2 ; HGR2
; Hires, no text at bottom
lda #8
sta EPOS
sta EPOS ; Unlike BASIC, our loop is *10
; 8 to 15 rather than .08 to .15
eloop: ; FOR E=.08 TO .15 STEP .01:
; .08 .09 .10 .11 .12 .13 .14
; 0 1 2 3 4 5 6
; EINT 8 9 10 11 12 13 14
; E*20 160 180 200 220 240 260 280
; 1.6 1.8 2.0 2.2 2.4 2.6 2.8
; 1 1 2 2 2 2 2
; E*25 200 225 250 275 300 325 350
; 2 2 2 2 3 3 3
; E*16 128 144 160 176 192 218 234
; 8 is E*100
; E*100/5 = 20
; E*80/4 = 20
; 6.4 7.2 8.0 8.8 9.6 10.4 11.2
; E*160/8 = 20
; 12.8 14.4 16.0 17.6 19.2
lda #4
eloop:
lda #4 ; FOR Y=4 to 189 STEP 6
sta YPOS
yloop: ; FOR Y=4 to 189 STEP 6
lda #4
yloop:
lda #4 ; FOR X=4 to 278 STEP 6
sta XPOS
lda #0
lda #0 ; can't fit 278 in one byte, need oflo
sta XPOSH
xloop: ; FOR X=4 to 278 STEP 6
xloop:
; SCALE=(RND(1)<E)*RND(1)*E*20+1
@ -190,41 +166,36 @@ done:
jsr XDRAW0 ; XDRAW 1 AT X,Y
; NEXT X
lda XPOS
clc
adc #6
sta XPOS
lda #0
adc XPOSH
sta XPOSH
beq xloop
lda XPOS
cmp #22
bcc xloop
nexty:
nextx: ; NEXT X
lda XPOS ; 2
clc ; 1
adc #6 ; x+=6 ; 2
sta XPOS ; 2
; NEXT Y
lda #0 ; inc high bit if we wrap past 256 ; 2
adc XPOSH ; 2
sta XPOSH ; 2
beq xloop ; if high byte zero, not at end ; 2
lda XPOS ; 2
cmp #22 ; see if less than 278 ; 2
bcc xloop ; if so, loop ; 2
;============
; 21
nexty: ; NEXT Y
lda YPOS
clc
adc #6
sta YPOS
cmp #189
bcc yloop
; NEXT E
; clc
; lda EPOS
; adc #16
; sta EPOS
; cmp #240
nexte: ; NEXT E
inc EPOS
lda EPOS
cmp #15
bcc eloop
jmp loop
jmp entropy
shape_table:
; .byte 1,0 ; 1 shape