From e4946e8b850628cc032739bdd29c679f9f8c0fa3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Herm=C3=A8s=20B=C3=A9lusca-Ma=C3=AFto?=
 <hermes.belusca-maito@reactos.org>
Date: Sun, 10 Nov 2013 16:22:33 +0000
Subject: [PATCH] [NTVDM] Instead of reassembling each time the very same
 common stub code for each interrupt, do it once, and then assemble just a
 little part for each interrupt and jump to the common stub. Now the 4DOS
 Ctrl-C exception bug changes, but I have an idea what's happening in there...

svn path=/branches/ntvdm/; revision=60917
---
 subsystems/ntvdm/int32.c | 44 +++++++++++++++++++++++++---------------
 1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/subsystems/ntvdm/int32.c b/subsystems/ntvdm/int32.c
index 9fcf573f7fe..4212709806f 100644
--- a/subsystems/ntvdm/int32.c
+++ b/subsystems/ntvdm/int32.c
@@ -128,25 +128,16 @@ VOID WINAPI Int32Dispatch(LPWORD Stack)
 
 VOID WINAPI InitializeInt32(WORD BiosSegment)
 {
-    USHORT i;
-    WORD Offset = 0;
-
     LPDWORD IntVecTable = (LPDWORD)BaseAddress;
-    LPBYTE BiosCode = (LPBYTE)SEG_OFF_TO_PTR(BiosSegment, 0);
+    LPBYTE  BiosCode    = (LPBYTE)SEG_OFF_TO_PTR(BiosSegment, 0);
 
-    /* Generate ISR stubs and fill the IVT */
-    for (i = 0x00; i <= 0xFF; i++)
+    USHORT i;
+    WORD CommonStub, BopSeqOffset, Offset;
+
+    CommonStub = Offset = 0x00;
+
+    /* Write the common stub code */
     {
-        IntVecTable[i] = MAKELONG(Offset, BiosSegment);
-
-        BiosCode[Offset++] = 0xFA; // cli
-
-        BiosCode[Offset++] = 0x6A; // push i
-        BiosCode[Offset++] = (UCHAR)i;
-
-        BiosCode[Offset++] = 0x6A; // push 0
-        BiosCode[Offset++] = 0x00;
-
 // BOP_SEQ:
         BiosCode[Offset++] = 0xF8; // clc
 
@@ -173,6 +164,27 @@ VOID WINAPI InitializeInt32(WORD BiosSegment)
 
         BiosCode[Offset++] = 0xCF; // iret
     }
+
+    /* Generate ISR stubs and fill the IVT */
+    for (i = 0x00; i <= 0xFF; i++)
+    {
+        IntVecTable[i] = MAKELONG(Offset, BiosSegment);
+
+        BiosCode[Offset++] = 0xFA; // cli
+
+        BiosCode[Offset++] = 0x6A; // push i
+        BiosCode[Offset++] = (UCHAR)i;
+
+        BiosCode[Offset++] = 0x6A; // push 0
+        BiosCode[Offset++] = 0x00;
+
+        BopSeqOffset = CommonStub - Offset - 3;
+
+        BiosCode[Offset+0] = 0xE9; // jmp near BOP_SEQ
+        BiosCode[Offset+1] = LOBYTE(BopSeqOffset);
+        BiosCode[Offset+2] = HIBYTE(BopSeqOffset);
+        Offset+=3;
+    }
 }
 
 VOID WINAPI RegisterInt32(BYTE IntNumber, EMULATOR_INT32_PROC IntHandler)