From fa82939cc5318a7b11af91d043f28c00da0480d7 Mon Sep 17 00:00:00 2001
From: Paul Gardner-Stephen <paul@servalproject.org>
Date: Sat, 20 Apr 2019 02:38:23 +0930
Subject: [PATCH] fix handling of printing $00 chars, and scanning $00 from
 keyboard matrix

---
 c64/kernal/chrout.s        | 5 +++++
 c64/kernal/scan_keyboard.s | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/c64/kernal/chrout.s b/c64/kernal/chrout.s
index ab3588b7..fde6a608 100644
--- a/c64/kernal/chrout.s
+++ b/c64/kernal/chrout.s
@@ -19,6 +19,11 @@ chrout:
 	
 	;; Check for special characters
 
+	cmp #$00
+	bne not_00
+	jmp chrout_done
+not_00:
+	
 	;; Linefeed (simply ignored)
 	;; Trivia: BASIC does CRLF with READY. prompt
 	cmp #$0a
diff --git a/c64/kernal/scan_keyboard.s b/c64/kernal/scan_keyboard.s
index 6b7bd3af..7fa2cc00 100644
--- a/c64/kernal/scan_keyboard.s
+++ b/c64/kernal/scan_keyboard.s
@@ -78,6 +78,8 @@ scan_keyboard:
 	and #$3f
 	tax
 	lda keyboard_matrixes,x
+	;; But don't insert $00 characters
+	beq +
 
 	;; Stash key into keyboard buffer
 	ldx keys_in_key_buffer
@@ -87,7 +89,6 @@ scan_keyboard:
 	inc keys_in_key_buffer
 	
 	*
-	lda keys_in_key_buffer
 
 	rts