From 8b955a500799093004e1e7ade7572d4509f7e4ca Mon Sep 17 00:00:00 2001
From: hugova <hugova@kth.se>
Date: Thu, 26 Jun 2025 22:05:08 +0200
Subject: [PATCH] very cool but not working circle.

---
 wip-hugo/routines/circle/circle.inc    |  8 ++++
 wip-hugo/routines/circle/circle.s      | 60 ++++++++++++++++++++++++++
 wip-hugo/routines/circle/circle_test.s |  9 ++++
 wip-hugo/source.s                      |  4 +-
 4 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 wip-hugo/routines/circle/circle.inc
 create mode 100644 wip-hugo/routines/circle/circle.s
 create mode 100644 wip-hugo/routines/circle/circle_test.s

diff --git a/wip-hugo/routines/circle/circle.inc b/wip-hugo/routines/circle/circle.inc
new file mode 100644
index 0000000..81ba847
--- /dev/null
+++ b/wip-hugo/routines/circle/circle.inc
@@ -0,0 +1,8 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
+.include "../pixel/pixel.inc"
+;; public args
+        radius = ARGVEC + 3
+;; private args
+        t1   = $E0
+        t2   = $E1
+        temp = $E2
diff --git a/wip-hugo/routines/circle/circle.s b/wip-hugo/routines/circle/circle.s
new file mode 100644
index 0000000..9c52deb
--- /dev/null
+++ b/wip-hugo/routines/circle/circle.s
@@ -0,0 +1,60 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
+
+.proc circle
+        .include "circle.inc"
+        ;; We use the algorithm jerkos method
+        ;; https://schwarzers.com/algorithms/
+        LDY Y_pos
+        LDX X_pos
+        ;; X_pos = X_pos + r (hack, should fix later ( xpos == ypos is not always true))
+        CLC
+        LDA X_pos
+        ADC radius
+        STA X_pos
+
+
+        ;; t1 = radius >> 4
+        LDA radius
+        LSR
+        LSR
+        LSR
+        LSR
+        STA t1
+while_x_bigger_then_y:
+
+        STY Y_pos
+        STX X_pos
+        STA temp
+        jsr pixel_draw
+        LDY Y_pos
+        LDX X_pos
+        LDA temp
+
+
+        INY ; y++
+
+        ;;t1 += y
+        CLC
+        LDA t1
+        STY temp
+        ADC temp
+        STA t1
+        ;; t2 = t1 -x
+        SEC
+        STX temp
+        SBC temp
+
+        ;; if t2 < 0 then skip to endif
+        CMP #$00
+        BMI endif
+if:
+        DEX; x--
+        STA t1; t1 = t2
+endif:
+        ;; repeat if X > Y
+        STX temp
+        TYA
+        CMP temp
+        JMP while_x_bigger_then_y
+        BEQ while_x_bigger_then_y
+.endproc
diff --git a/wip-hugo/routines/circle/circle_test.s b/wip-hugo/routines/circle/circle_test.s
new file mode 100644
index 0000000..de42b01
--- /dev/null
+++ b/wip-hugo/routines/circle/circle_test.s
@@ -0,0 +1,9 @@
+.scope circle_test
+        .include "circle.inc"
+        LDA #$50
+        STA X_pos
+        STA Y_pos
+        LDA #$08
+        STA radius
+        JSR circle
+.endscope
diff --git a/wip-hugo/source.s b/wip-hugo/source.s
index 6cca178..5aa440e 100755
--- a/wip-hugo/source.s
+++ b/wip-hugo/source.s
@@ -9,7 +9,8 @@
 ;.include "dubbel_buffer/raster_irqs.s"
 
 ;.include "routines/arithmatic/mult_test.s"
-.include "routines/arithmatic/div_test.s"
+;.include "routines/arithmatic/div_test.s"
+.include "routines/circle/circle_test.s"
 ;.include "routines/line/line_test.s"
 ;.include "routines/text/char_draw_test.s"
 ;.include "routines/pixel/pixel_test.s"
@@ -20,6 +21,7 @@ exit:
 JMP exit
 .include "../wip-duuqnd/public.inc"
 .include "routines/line/line.s"
+.include "routines/circle/circle.s"
 .include "routines/triangle/triangle.s"
 .include "routines/pixel/pixel_draw.s"
 .include "routines/text/char_draw.s"