From: Alan Cox <alan@linux.intel.com>
Date: Sun, 18 Nov 2018 22:07:03 +0000 (+0000)
Subject: sam: fix crash with esc-J on the bottom line
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=8f8ed125885657ef5fcf9e9b44008ca7bdeac39c;p=FUZIX.git

sam: fix crash with esc-J on the bottom line
---

diff --git a/Kernel/platform-sam/README b/Kernel/platform-sam/README
index 8c8d1158..a6911239 100644
--- a/Kernel/platform-sam/README
+++ b/Kernel/platform-sam/README
@@ -106,3 +106,4 @@ DONE	-	RTC driver
 DONE	-	Mouse/Joystick/Input
 DONE	-	Review and test signal handling paths more (catching signals
 		path appears to be broken)
+DONE	-	Esc-J crashes the console driver
diff --git a/Kernel/platform-sam/sam_vt.s b/Kernel/platform-sam/sam_vt.s
index d6811952..3728eee9 100644
--- a/Kernel/platform-sam/sam_vt.s
+++ b/Kernel/platform-sam/sam_vt.s
@@ -164,6 +164,8 @@ _clear_lines:
 	push de
 	push hl
 	ld a,d			; count (0-23)
+	or a
+	ret z			; zero count is possible - do nothing
 	ld d,#0
 	; Now how much to copy ?
 	; 128 bytes per scan line, 8 scan lines per char = 1024