From 29bb526d20c8067d6a102edccb80bcd5ef50c01a Mon Sep 17 00:00:00 2001
From: ripsaw8080 <ripsaw8080@users.sourceforge.net>
Date: Sat, 28 Oct 2017 19:49:11 +0000
Subject: [PATCH] Implement update region in mouse driver; only text modes for
 now. Fixes mouse pointer problems in Microsoft Programmer's Library.

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@4062
---
 src/ints/mouse.cpp | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/src/ints/mouse.cpp b/src/ints/mouse.cpp
index 4eee708e..7b6676ca 100644
--- a/src/ints/mouse.cpp
+++ b/src/ints/mouse.cpp
@@ -113,8 +113,8 @@ static struct {
 	Bit16u	dspeed_val;
 	float	senv_x;
 	float	senv_y;
-	Bit16u  updateRegion_x[2];
-	Bit16u  updateRegion_y[2];
+	Bit16s  updateRegion_x[2];
+	Bit16s  updateRegion_y[2];
 	Bit16u  doubleSpeedThreshold;
 	Bit16u  language;
 	Bit16u  cursorType;
@@ -251,6 +251,11 @@ void DrawCursorText() {
 	// Restore Background
 	RestoreCursorBackgroundText();
 
+	// Check if cursor in update region
+	if ((POS_Y <= mouse.updateRegion_y[1]) && (POS_Y >= mouse.updateRegion_y[0]) &&
+		(POS_X <= mouse.updateRegion_x[1]) && (POS_X >= mouse.updateRegion_x[0])) {
+		return;
+	}
 
 	// Save Background
 	mouse.backposx		= POS_X>>3;
@@ -674,10 +679,7 @@ void Mouse_AfterNewVideoMode(bool setmode) {
 	mouse.language   = 0;
 	mouse.page               = 0;
 	mouse.doubleSpeedThreshold = 64;
-	mouse.updateRegion_x[0] = 1;
-	mouse.updateRegion_y[0] = 1;
-	mouse.updateRegion_x[1] = 1;
-	mouse.updateRegion_y[1] = 1;
+	mouse.updateRegion_y[1] = -1; //offscreen
 	mouse.cursorType = 0; //Test
 	mouse.enabled=true;
 
@@ -716,6 +718,7 @@ static Bitu INT33_Handler(void) {
 		break;
 	case 0x01:	/* Show Mouse */
 		if(mouse.hidden) mouse.hidden--;
+		mouse.updateRegion_y[1] = -1; //offscreen
 		Mouse_AutoLock(true);
 		DrawCursor();
 		break;
@@ -838,11 +841,12 @@ static Bitu INT33_Handler(void) {
 	case 0x0f:	/* Define mickey/pixel rate */
 		Mouse_SetMickeyPixelRate(reg_cx,reg_dx);
 		break;
-	case 0x10:      /* Define screen region for updating */
-		mouse.updateRegion_x[0]=reg_cx;
-		mouse.updateRegion_y[0]=reg_dx;
-		mouse.updateRegion_x[1]=reg_si;
-		mouse.updateRegion_y[1]=reg_di;
+	case 0x10:	/* Define screen region for updating */
+		mouse.updateRegion_x[0]=(Bit16s)reg_cx;
+		mouse.updateRegion_y[0]=(Bit16s)reg_dx;
+		mouse.updateRegion_x[1]=(Bit16s)reg_si;
+		mouse.updateRegion_y[1]=(Bit16s)reg_di;
+		DrawCursor();
 		break;
 	case 0x11:      /* Get number of buttons */
 		reg_ax=0xffff;