6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2024-06-01 13:41:34 +00:00
Code Issues Projects Releases Wiki Activity

Cleanup

Browse Source
This commit is contained in:
Dave Plummer 2023-10-09 17:38:37 -07:00
parent 6cd039469c
commit c6cca00513
1 changed files with 36 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
samples/kim1/subs.asm
View File

@ -21,44 +21,44 @@
SCREEN = $A000
.segment "ZEROPAGE"
btpt: .res 1
_x1cord: .res 2
_x2cord: .res 2
_y1cord: .res 2
_y2cord: .res 2
btpt: .res 1
dest:
dest_lo: .res 1
dest_hi: .res 1
dest_lo: .res 1
dest_hi: .res 1
src:
src_lo: .res 1
src_hi: .res 1
src_lo: .res 1
src_hi: .res 1
adp1:
adp1_lo: .res 1
adp1_hi: .res 1
adp1_lo: .res 1
adp1_hi: .res 1
adp2:
adp2_lo: .res 1
adp2_hi: .res 1
.exportzp _x1cord
.exportzp _x2cord
.exportzp _y1cord
.exportzp _y2cord
adp2_lo: .res 1
adp2_hi: .res 1
.segment "DATA"
xval: .res 2
yval: .res 2
_x1cord: .res 2
_x2cord: .res 2
_y1cord: .res 2
_y2cord: .res 2
xval: .res 2 ; These could move to zeropage for perf, but presume we
yval: .res 2 ; we want to minimize the amount we grow zero page use
err: .res 2
temp: .res 2
temp2: .res 2
x0: .res 2
y0: .res 2
.export _x1cord ; Make sure these show up on the C side as zero page
.export _x2cord
.export _y1cord
.export _y2cord
.segment "CODE"
;-----------------------------------------------------------------------------------
@ -236,9 +236,6 @@ _ScrollScreen:
;-----------------------------------------------------------------------------------
; Implements the midpoint circle algorithm without floating point or trig functions
;-----------------------------------------------------------------------------------
; void DrawCircle(int x0, int y0, int radius, byte val)
; {
; int x = radius;
; int y = 0;
; int err = 0;
@ -261,22 +258,22 @@ _ScrollScreen:
; err += 1 - 2 * x;
; }
; }
; }
_DrawCircle: lda _x1cord ; x0 = _x1cord
;-----------------------------------------------------------------------------------
_DrawCircle: lda _x1cord ; x0 = _x1cord
sta x0
lda _x1cord+1
sta x0+1
lda _y1cord ; y0 = _y1cord
lda _y1cord ; y0 = _y1cord
sta y0
lda _y1cord+1
sta y0+1
lda _y2cord ; x = radius
lda _y2cord ; x = radius
sta xval
lda _y2cord+1
sta xval+1
lda #$0 ; yval = 0;
sta yval
sta yval+1
@ -294,8 +291,7 @@ circleloop:
doneCircle: rts
doCircle:
lda x0 ; Draw the first of 8 symmetric quadrant copies
doCircle: lda x0 ; Draw the first of 8 symmetric quadrant copies
clc
adc yval
sta _x1cord
@ -310,8 +306,7 @@ doCircle:
sbc xval+1
sta _y1cord+1
jsr _SetPixel ; SETPIXEL(x0 + y, y0 - x, val);
lda x0
sec
sbc yval
@ -423,7 +418,7 @@ doCircle:
adc xval+1
sta _y1cord+1
jsr _SetPixel ; SETPIXEL(x0 - y, y0 + x, val);
inc yval ; yval++;
bne :+
inc yval+1
@ -454,22 +449,18 @@ doCircle:
sbc xval+1
sta temp+1
lda temp ; temp will now be 2*(err-xval)+1
asl
sta temp
lda temp+1
rol
sta temp+1
asl temp ; temp = 2*(err-xval)+1
rol temp+1
inc temp
bne :+
inc temp+1
:
lda temp+1 ; if (temp > 0) we'll dec xval
bmi doneLoop ; less than zero, so no dec
lda temp+1 ; if (temp > 0) we'll dec xval
bmi doneLoop ; less than zero, so no dec
bne decxval ; if not zero, go ahead and dec
lda temp ; MSb is zero so now check the LSB
beq doneLoop ; both bytes are zero, so no dec
lda temp ; MSB is zero so now check the LSB
beq doneLoop ; both bytes are zero, so no dec
decxval: lda xval ; xval--
bne :+
@ -483,7 +474,7 @@ updateerr: lda xval ; temp = xval * 2
rol
sta temp+1
lda #1 ; temp2 = 1-(xval*2)
lda #1 ; temp2 == 1-temp == 1-(xval*2)
sec
sbc temp
sta temp2