From b4721ae46b0399deeffed8cf2eca6f3eb9feed5f Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Sun, 22 Jan 2023 09:37:37 -0800
Subject: [PATCH] fix pixel shift

---
 mandel.s | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mandel.s b/mandel.s
index 9d3a2a6..df80ed7 100644
--- a/mandel.s
+++ b/mandel.s
@@ -584,6 +584,9 @@ point:
     ; pixel_mask <<= pixel_shift (shifting in ones)
     and #3
     sta pixel_shift
+    lda #3
+    sec
+    sbc pixel_shift
     tax
 shift_loop:
     beq shift_done