winedos / Fix real mode interrupt vector access under Win16

[Jukka Heinonen <jhei@iki.fi>]

This patch should fix crash in 16-bit code reported
on wine-devel. This is actually the same problem as
with BIOS data area. Under Win16, real mode vectors
may have been moved to another location and a bit more
complex code must be used to access them.





Changelog:
  Use correct pointer when accessing real mode interrupt
  vectors under Win16.





Index: dlls/winedos/interrupts.c
===================================================================
RCS file: /home/wine/wine/dlls/winedos/interrupts.c,v
retrieving revision 1.21
diff -u -r1.21 interrupts.c
--- dlls/winedos/interrupts.c	4 Oct 2003 03:06:18 -0000	1.21
+++ dlls/winedos/interrupts.c	6 Oct 2003 21:03:57 -0000
@@ -72,6 +72,27 @@
 
 
 /**********************************************************************
+ *         DOSVM_GetRMVector
+ *
+ * Return pointer to real mode interrupt vector. These are not at fixed 
+ * location because those Win16 programs that do not use any real mode 
+ * code have protected NULL pointer catching block at low linear memory 
+ * and interrupt vectors have been moved to another location.
+ */
+static FARPROC16* DOSVM_GetRMVector( BYTE intnum )
+{
+    LDT_ENTRY entry;
+    FARPROC16 proc;
+
+    proc = GetProcAddress16( GetModuleHandle16( "KERNEL" ), 
+                             (LPCSTR)(ULONG_PTR)183 );
+    wine_ldt_get_entry( LOWORD(proc), &entry );
+
+    return (FARPROC16*)wine_ldt_get_base( &entry ) + intnum;
+}
+
+
+/**********************************************************************
  *         DOSVM_IsIRQ
  *
  * Return TRUE if interrupt is an IRQ.
@@ -517,7 +538,7 @@
  */
 FARPROC16 DOSVM_GetRMHandler( BYTE intnum )
 {
-  return ((FARPROC16*)0)[intnum];
+  return *DOSVM_GetRMVector( intnum );
 }
 
 
@@ -530,7 +551,7 @@
 {
   TRACE("Set real mode interrupt vector %02x <- %04x:%04x\n",
        intnum, HIWORD(handler), LOWORD(handler) );
-  ((FARPROC16*)0)[intnum] = handler;
+  *DOSVM_GetRMVector( intnum ) = handler;
 }
 
 



-- 
Jukka Heinonen <http://www.iki.fi/jhei/>