don't clobber si on int33/3 calls, this breaks qbasic.com

3 files changed, 24 insertions, 9 deletions

diff --git a/doc/wheelapi2.txt b/doc/wheelapi2.txt
index d1f6fb3..c2b087f 100644
--- a/doc/wheelapi2.txt
+++ b/doc/wheelapi2.txt
@@ -24,21 +24,23 @@ INT 33/0003 - Get cursor position, buttons status and wheel counter
 Return:	BL = buttons status (bits 0-4)
     CX = column
     DX = row
-    BH = 8-bit signed counter of wheel movement since last call
+    BH = 8-bit signed counter of wheel movement since last call.
           positive value means downward wheel movement.
-    SI = 16-bit signed counter of 2nd wheel movement since last call
+    AH = 8-bit signed counter of 2nd wheel movement since last call.
           positive value means rightward wheel movement.
 Note:   calling this clears the wheel counter for ALL wheels.
 
 INT 33/0005 - Get button press or wheel movement data
     AX = 0005h
     BX = button number, -1 for vertical wheel, -2 for 2nd/horizontal wheel
+    (return values remain the same)
 Note:   as in wheelapi v1, AH always contains (1st) wheel movement on return
           independently of button number requested in BX.
 
 INT 33/0006 - Get button release or wheel movement data
     AX = 0006h
     BX = button number, -1 for vertical wheel, -2 for 2nd/horizontal wheel
+    (return values remain the same)
 
 INT 33/000C - Define User Interrupt Routine
 INT 33/0014 - Exchange User Interrupt Routines
diff --git a/mousetsr.c b/mousetsr.c
index 2afc2b4..e571d51 100644
--- a/mousetsr.c
+++ b/mousetsr.c
@@ -989,7 +989,7 @@ static void reset_mouse_hardware()
 	data.packet_size = PS2M_PACKET_SIZE_STD;
 	data.cur_packet_bytes = 0;
 	data.cur_packet_ticks = 0;
-	data.num_buttons = 3;
+	data.num_buttons = MIN(3, MAX_BUTTONS);
 #if USE_WHEEL
 	data.num_wheels = 0;
 	data.usewheelapi = 0;
@@ -1037,7 +1037,7 @@ static void reset_mouse_hardware()
 		dputs("ImPS/2 detected");
 		data.packet_size = PS2M_PACKET_SIZE_EXT;
 
-		data.num_wheels = 1;
+		data.num_wheels = MIN(1, MAX_WHEELS);
 		ps2m_get_device_id(&data.device_id);
 
 #if USE_IMEX
@@ -1059,12 +1059,13 @@ static void reset_mouse_hardware()
 		if (data.device_id == PS2M_DEVICE_ID_IMEX
 		        || data.device_id == PS2M_DEVICE_ID_IMEX_HORZ) {
 			dputs("ImEx detected");
-			data.num_wheels = 2;
-			data.num_buttons = 5;
+			data.num_wheels = MIN(2, MAX_WHEELS);
+			data.num_buttons = MIN(5, MAX_BUTTONS);
 		}
 #endif /* USE_IMEX */
 
-		dprintf("found mouse device id = 0x%hx\n", data.device_id);
+		dprintf("found mouse device id = 0x%hx num buttons=%d num wheels=%d\n",
+		        data.device_id, data.num_buttons, data.num_wheels);
 	} else {
 		if (data.usewheel) dputs("PS/2 wheel NOT detected");
 	}
@@ -1140,11 +1141,13 @@ static void reset_mouse_state()
 		data.button[i].released.last.x = 0;
 		data.button[i].released.last.y = 0;
 	}
+#if USE_WHEEL
 	for (i = 0; i < MAX_WHEELS; i++) {
 		data.wheel[i].delta = 0;
 		data.wheel[i].last.x = 0;
 		data.wheel[i].last.y = 0;
 	}
+#endif
 	data.cursor_visible = false;
 	data.cursor_pos.x = 0;
 	data.cursor_pos.y = 0;
@@ -1152,6 +1155,7 @@ static void reset_mouse_state()
 	memset(data.cursor_prev_graphic, 0, sizeof(data.cursor_prev_graphic));
 }
 
+#if USE_WHEEL
 /** Return (in the appropiate registers) the wheel movement counter and afterwards reset it. */
 static void return_clear_wheel_counter(union INTPACK __far *r, struct wheelcounter *c)
 {
@@ -1160,6 +1164,7 @@ static void return_clear_wheel_counter(union INTPACK __far *r, struct wheelcount
 	r->w.bx = c->delta;
 	c->delta = 0;
 }
+#endif
 
 /** Return (in the appropiate registers) the desired button press counter and afterwards reset it. */
 static void return_clear_button_counter(union INTPACK __far *r, struct buttoncounter *c)
@@ -1223,8 +1228,10 @@ static void int33_handler(union INTPACK r)
 		if (data.num_wheels > 0) {
 			r.h.bh = data.wheel[0].delta;
 			data.wheel[0].delta = 0;
-			r.x.si = data.wheel[1].delta;
-			data.wheel[1].delta = 0;
+			if (data.num_wheels > 1) {
+				r.h.ah = data.wheel[1].delta;
+				data.wheel[1].delta = 0;
+			}
 		}
 #endif
 		break;
diff --git a/mousetsr.h b/mousetsr.h
index 5f98333..5625ae1 100644
--- a/mousetsr.h
+++ b/mousetsr.h
@@ -63,7 +63,13 @@
 #define MAX_BUTTONS 5
 
 /** Maximum number of wheels supported. */
+#if USE_IMEX
 #define MAX_WHEELS 2
+#elif USE_WHEEL
+#define MAX_WHEELS 1
+#else
+#define MAX_WHEELS 0
+#endif
 
 /** Size of int33 graphic cursor shape definitions. */
 #define GRAPHIC_CURSOR_WIDTH 16