From eff01e5411f90a2cfe7b2861adadc171e6ed4b35 Mon Sep 17 00:00:00 2001
From: hugova <hugova@kth.se>
Date: Fri, 1 Aug 2025 19:24:40 +0200
Subject: [PATCH] make circle draw not write over program mem.

---
 host/src/routines/circle/circle.s               | 13 +++++++++++++
 host/src/routines/circle/circle_test_position.s |  4 ++--
 host/src/routines/circle/circle_test_size.s     |  2 +-
 host/src/test.s                                 | 12 ++++++------
 4 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/host/src/routines/circle/circle.s b/host/src/routines/circle/circle.s
index 81428b5..e58b3b3 100644
--- a/host/src/routines/circle/circle.s
+++ b/host/src/routines/circle/circle.s
@@ -45,6 +45,8 @@ draw_upper_px_in_circle:
         SBC radius
         STA Y_pos
 
+        BCC outside_screen_error
+
         JSR  pixel_calc
        	;; A = byte_to_paint (small_X_offset)
 	;; Y =small_y_offset
@@ -93,6 +95,11 @@ draw_lower_px_in_circle: ;similar as above
         ADC radius
         STA Y_pos
 
+        ;; Stop this if overflow or if outside screen.
+        BCS outside_screen_error
+        CMP #$C8 ;; Screen width
+        BCS outside_screen_error
+
         JSR  pixel_calc
        	;; A = byte_to_paint (small_X_offset)
 	;; Y =small_y_offset
@@ -132,8 +139,13 @@ draw_right_px_in_circle:; similar as above
         STY Y_qaa
 
 
+JMP outside_screen_error_end
+outside_screen_error:
+RTS
+outside_screen_error_end:
         LDX #$08 ; X=8 always expected inside the loop
         SEC
+
 while_x_bigger_then_y: ; C=1 here because above and branching logic
 draw_pixels:
 draw_qaa:
@@ -286,4 +298,5 @@ endif:
         jmp while_x_bigger_then_y
 end:
         RTS
+
 .endproc
diff --git a/host/src/routines/circle/circle_test_position.s b/host/src/routines/circle/circle_test_position.s
index ffa296f..89635a4 100644
--- a/host/src/routines/circle/circle_test_position.s
+++ b/host/src/routines/circle/circle_test_position.s
@@ -2,7 +2,7 @@
         .include "circle.inc"
 
         ;; Set initial parameters for circle
-        LDA #$50
+        LDA #$00
         STA $AD
         LDA #$50
         STA $AE
@@ -38,6 +38,6 @@ loop:
 
         ;; end loop when x_pos = $70
         LDA $AD
-        CMP #$70
+        CMP #$ff
         BNE loop
 .endscope
diff --git a/host/src/routines/circle/circle_test_size.s b/host/src/routines/circle/circle_test_size.s
index 1c9093a..558f8e2 100644
--- a/host/src/routines/circle/circle_test_size.s
+++ b/host/src/routines/circle/circle_test_size.s
@@ -37,6 +37,6 @@ loop:
 
         ;; end loop if radius = $aa
         LDA $AD
-        CMP #$20
+        CMP #$ff
         BNE loop
 .endscope
diff --git a/host/src/test.s b/host/src/test.s
index 43b4300..467ca40 100644
--- a/host/src/test.s
+++ b/host/src/test.s
@@ -15,12 +15,12 @@
 mainsetup:
 ;; Note that arithmetic tests may use upp all the memory and the compiler don't complain!
 ;.include "routines/arithmatic/mult_test.s"
-.include "routines/arithmatic/div_test.s"
+;.include "routines/arithmatic/div_test.s"
 ;.include "routines/arithmatic/div_test_zero.s"
 
-;.include "routines/circle/circle_test.s"
-;.include "routines/circle/circle_test_size.s"
-;.include "routines/circle/circle_test_position.s"
+.include "routines/circle/circle_test.s"
+.include "routines/circle/circle_test_size.s"
+.include "routines/circle/circle_test_position.s"
 ;.include "routines/line/line_test.s"
 ;.include "routines/line/line_test_extensive.s"
 ;.include "routines/text/char_draw_test.s"
@@ -33,10 +33,10 @@ exit:
 JMP exit
 .include "public.inc"
 ;.include "routines/line/line.s"
-;.include "routines/circle/circle.s"
+.include "routines/circle/circle.s"
 ;.include "routines/triangle/triangle.s"
 .include "routines/pixel/pixel_draw.s"
-;.include "routines/pixel/pixel_calc.s"
+.include "routines/pixel/pixel_calc.s"
 ;.include "routines/pixel/misc_pixel.s"
 ;.include "routines/text/char_draw.s"
 .include "routines/memory/memset.s"