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--- base:circle_routine [2020-04-12 18:35] – created verz
+++ base:circle_routine [2020-04-19 19:24] (current) – verz
@@ Line 1: / Line 1: @@
+====== Circle Routine ======
 Circle routine, on the bitmap screen, based on algorithm at:  [[http://ffd2.com/fridge/chacking/c=hacking9.txt]]. Draws the Circle with 8 symmetric arcs.
-<code>
+<code 6502acme>
 _Vic = $d000
 _Vmem= $2000
@@ Line 20: / Line 22: @@
 ;       input: pX1 (word 0-319**), center x-coord
 ;              pY1 (byte 0-199**), center y-coord
-;              pXR (byte 0-320**), radius
+;              pXR (word 0-320**), radius
 ;       **values can in fact be larger: Y can be up to 255
 ;       while X and R can be up to 65535 (X in 0-32767 for
@@ Line 157: / Line 159: @@
         jsr CheckPlot
-        lda yoMy        ; ****** 6. SSW, arc 5
+        lda yoMy        ; ****** 6. ENE, arc 2
         sta pY
         jsr CheckPlot
-        lda xoMx        ; ****** 7. WSW, arc 6
+        lda xoMx        ; ****** 7. WNW, arc 7
         sta pX
         lda xoMx+1
@@ Line 167: / Line 169: @@
         jsr CheckPlot
-        lda yoPy        ; ****** 8. SSE, arc 4
+        lda yoPy        ; ****** 8. WSW, arc 6
         sta pY
         jsr CheckPlot
-        lda xoPy        ; ****** 9. WNW, arc 7
+        lda xoPy        ; ****** 9. SSE, arc 4
         sta pX
         lda xoPy+1
@@ Line 183: / Line 185: @@
         jsr CheckPlot
-        lda xoMy        ; ****** 11. ENE, arc 2
+        lda xoMy        ; ****** 11. NNW, arc 8
         sta pX
         lda xoMy+1
@@ Line 189: / Line 191: @@
         jsr CheckPlot
-        lda yoPx        ; ****** 12. NNW, arc 8
+        lda yoPx        ; ****** 12. SSW, arc 5
         sta pY
         jsr CheckPlot