Files
scorch_src/circle1.asm
T
2024-11-05 18:13:10 +01:00

204 lines
3.0 KiB
NASM

.IF *>0 ;this is a trick that prevents compiling this file alone
;--------------------------------------------------
.proc circle ;fxxxing good circle drawing :)
; xdraw,ydraw (word) - coordinates of circle center
; radius (byte) - radius of circle
;--------------------------------------------------
;Turbo Basic source
; R=30
; XC=0:YC=R
; FX=0:FY=8*R:FS=4*R+3
; WHILE FX<FY
; splot8 //splot8 are eight plotz around the circle
; XC=XC+1
; FX=FX+8
; IF FS>0
; FS=FS-FX-4
; ELSE
; YC=YC-1
; FY=FY-8
; FS=FS-FX-4+FY
; ENDIF
; WEND
; splot8
mwa xdraw xcircle
mwa ydraw ycircle
; XC=0:YC=R
mwa #0 xc
mva radius yc
; FX=0:FY=8*R:FS=4*R+3
mva #0 fx
mva radius fy
asl FY
asl FY
mva FY FS
asl FY
; A = FS and C = 0
;clc
;lda FS
adc #3
sta FS
circleloop
; WHILE FX<FY
lda FX
cmp FY
bcc not_endcircleloop
endcircleloop
mwa xcircle xdraw
mwa ycircle ydraw
rts
not_endcircleloop
; jsr splot8
;----
; splot8
; plot xcircle+XC,ycircle+YC
; plot xcircle+XC,ycircle-YC
; plot xcircle-XC,ycircle-YC
; plot xcircle-XC,ycircle+YC
; plot xcircle+YC,ycircle+XC
; plot xcircle+YC,ycircle-XC
; plot xcircle-YC,ycircle-XC
; plot xcircle-YC,ycircle+XC
;clc - allways after BCC
lda xcircle
adc XC
sta xdraw
lda xcircle+1
adc #0
sta xdraw+1
;clc
lda ycircle
adc YC
sta ydraw
sta ytempDRAW
lda ycircle+1
adc #$00
sta ydraw+1
sta ytempDRAW+1
; plot xcircle+XC,ycircle+YC
jsr plot
sec
lda ycircle
sbc YC
sta ydraw
lda ycircle+1
sbc #$00
sta ydraw+1
; plot xcircle+XC,ycircle-YC
jsr plot
sec
lda xcircle
sbc XC
sta xdraw
lda xcircle+1
sbc #0
sta xdraw+1
; plot xcircle-XC,ycircle-YC
jsr plot
lda ytempDRAW
sta ydraw
lda ytempDRAW+1
sta ydraw+1
; plot xcircle-XC,ycircle+YC
jsr plot
;---
clc
lda xcircle
adc YC
sta xdraw
lda xcircle+1
adc #0
sta xdraw+1
;clc
lda ycircle
adc XC
sta ydraw
sta ytempDRAW
lda ycircle+1
adc #$00
sta ydraw+1
sta ytempDRAW+1
; plot xcircle+YC,ycircle+XC
jsr plot
sec
lda ycircle
sbc XC
sta ydraw
lda ycircle+1
sbc #$00
sta ydraw+1
; plot xcircle+YC,ycircle-XC
jsr plot
sec
lda xcircle
sbc YC
sta xdraw
lda xcircle+1
sbc #0
sta xdraw+1
; plot xcircle-YC,ycircle-XC
jsr plot
lda ytempDRAW
sta ydraw
lda ytempDRAW+1
sta ydraw+1
; plot xcircle-YC,ycircle+XC
jsr plot
;-----
; XC=XC+1
inc XC
; FX=FX+8
clc
lda FX
adc #8
sta FX
; IF FS>0
; FS=FS-FX-4
lda FS
beq else01
bmi else01
sec
sbc FX
sbc #4
sta FS
jmp circleloop ; endif01
else01
; ELSE
; YC=YC-1
dec YC
; FY=FY-8
sec
lda FY
sbc #8
sta FY
; FS=FS-FX-4+FY
lda FS
sec
sbc FX
sbc #4
clc
adc FY
sta FS
endif01
; ENDIF
jmp circleloop
; WEND
.endp
.endif