From 193a19846230cd653ca61b65d54538974116c1ea Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Wed, 5 Oct 2011 13:28:36 +0800
Subject: [PATCH] Kernel - Fixed vterm corruption at end of buffer

---
 Kernel/drv/vterm.c     | 20 ++++++++++++--------
 Kernel/include/acess.h |  1 +
 Kernel/lib.c           | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/Kernel/drv/vterm.c b/Kernel/drv/vterm.c
index b342a78f..1d4b3672 100644
--- a/Kernel/drv/vterm.c
+++ b/Kernel/drv/vterm.c
@@ -24,6 +24,7 @@
 #define	DEFAULT_WIDTH	640
 #define	DEFAULT_HEIGHT	480
 #define DEFAULT_SCROLLBACK	2	// 2 Screens of text + current screen
+//#define DEFAULT_SCROLLBACK	0
 #define	DEFAULT_COLOUR	(VT_COL_BLACK|(0xAAA<<16))
 
 #define	VT_FLAG_HIDECSR	0x01
@@ -802,10 +803,10 @@ void VT_KBCallBack(Uint32 Codepoint)
 		case KEY_PGDOWN:
 			if( gpVT_CurTerm->Flags & VT_FLAG_ALTBUF )
 				return ;
-			if( gpVT_CurTerm->ViewPos < gpVT_CurTerm->Width*gpVT_CurTerm->Height*(giVT_Scrollback-1) )
+			if( gpVT_CurTerm->ViewPos < gpVT_CurTerm->Width*gpVT_CurTerm->Height*(giVT_Scrollback) )
 				gpVT_CurTerm->ViewPos += gpVT_CurTerm->Width;
 			else
-				gpVT_CurTerm->ViewPos = gpVT_CurTerm->Width*gpVT_CurTerm->Height*(giVT_Scrollback-1);
+				gpVT_CurTerm->ViewPos = gpVT_CurTerm->Width*gpVT_CurTerm->Height*(giVT_Scrollback);
 			return;
 		}
 	}
@@ -1351,7 +1352,8 @@ void VT_int_ScrollText(tVTerm *Term, int Count)
 	 int	height, init_write_pos;
 	 int	len, i;
 	 int	scroll_top, scroll_height;
-	
+
+	// Get buffer pointer and attributes	
 	if( Term->Flags & VT_FLAG_ALTBUF )
 	{
 		buf = Term->AltBuf;
@@ -1363,22 +1365,24 @@ void VT_int_ScrollText(tVTerm *Term, int Count)
 	else
 	{
 		buf = Term->Text;
-		height = Term->TextHeight*giVT_Scrollback;
+		height = Term->TextHeight*(giVT_Scrollback+1);
 		init_write_pos = Term->WritePos;
 		scroll_top = 0;
 		scroll_height = height;
 	}
-	
+
+	// Scroll text downwards	
 	if( Count > 0 )
 	{
 		 int	base;
+	
+		// Set up
 		if(Count > scroll_height)	Count = scroll_height;
-//		Debug("Scroll: Count = %i", Count);
 		base = Term->TextWidth*(scroll_top + scroll_height - Count);
 		len = Term->TextWidth*(scroll_height - Count);
 		
 		// Scroll terminal cache
-		memcpy(
+		memmove(
 			&buf[Term->TextWidth*scroll_top],
 			&buf[Term->TextWidth*(scroll_top+Count)],
 			len*sizeof(tVT_Char)
@@ -1413,7 +1417,7 @@ void VT_int_ScrollText(tVTerm *Term, int Count)
 		len = Term->TextWidth*(scroll_height - Count);
 		
 		// Scroll terminal cache
-		memcpy(
+		memmove(
 			&buf[Term->TextWidth*(scroll_top+Count)],
 			&buf[Term->TextWidth*scroll_top],
 			len*sizeof(tVT_Char)
diff --git a/Kernel/include/acess.h b/Kernel/include/acess.h
index 5df49c12..3d0b3b32 100644
--- a/Kernel/include/acess.h
+++ b/Kernel/include/acess.h
@@ -328,6 +328,7 @@ extern int	MM_GetPageNode(tPAddr PAddr, void **Node);
 extern int	memcmp(const void *m1, const void *m2, size_t count);
 extern void	*memcpy(void *dest, const void *src, size_t count);
 extern void	*memcpyd(void *dest, const void *src, size_t count);
+extern void	*memmove(void *dest, const void *src, size_t len);
 extern void	*memset(void *dest, int val, size_t count);
 extern void	*memsetd(void *dest, Uint32 val, size_t count);
 /**
diff --git a/Kernel/lib.c b/Kernel/lib.c
index 28edc561..c4251a63 100644
--- a/Kernel/lib.c
+++ b/Kernel/lib.c
@@ -81,6 +81,7 @@ EXPORT(ModUtil_SetIdent);
 EXPORT(UnHex);
 EXPORT(SwapEndian16);
 EXPORT(SwapEndian32);
+EXPORT(memmove);
 
 // === CODE ===
 /**
@@ -948,3 +949,35 @@ Uint32 SwapEndian32(Uint32 Val)
 {
 	return ((Val&0xFF)<<24) | ((Val&0xFF00)<<8) | ((Val>>8)&0xFF00) | ((Val>>24)&0xFF);
 }
+
+void *memmove(void *__dest, const void *__src, size_t len)
+{
+	size_t	block_size;
+	char	*dest = __dest;
+	const char	*src = __src;
+	void	*ret = __dest;
+	
+	if( (tVAddr)dest > (tVAddr)src + len )
+		return memcpy(dest, src, len);
+	if( (tVAddr)dest + len < (tVAddr)src )
+		return memcpy(dest, src, len);
+	
+	if( (tVAddr)dest < (tVAddr)src )
+		block_size = (tVAddr)src - (tVAddr)dest;
+	else
+		block_size = (tVAddr)dest - (tVAddr)src;
+	
+	block_size &= ~0xF;
+	
+	while(len >= block_size)
+	{
+		memcpy(dest, src, block_size);
+		len -= block_size;
+		dest += block_size;
+		src += block_size;
+	}
+	memcpy(dest, src, len);
+	return ret;
+	
+}
+
-- 
2.20.1