From fa940c2075f74ee60aa997d388e7e367b1cc3c51 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: Sat, 9 Nov 2013 16:11:52 +0000
Subject: [PATCH] [NTVDM] DOS: Implement INT 21h, AH 62h as a call to INT 21h,
 AH 51h.

svn path=/branches/ntvdm/; revision=60899
---
 subsystems/ntvdm/dos.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/subsystems/ntvdm/dos.c b/subsystems/ntvdm/dos.c
index 59ec0fb0513..bd531ca0f3e 100644
--- a/subsystems/ntvdm/dos.c
+++ b/subsystems/ntvdm/dos.c
@@ -1598,7 +1598,7 @@ VOID DosInt21h(LPWORD Stack)
             break;
         }
 
-        /* Disk Reset  */
+        /* Disk Reset */
         case 0x0D:
         {
             PDOS_PSP PspBlock = SEGMENT_TO_PSP(CurrentPsp);
@@ -2328,9 +2328,14 @@ VOID DosInt21h(LPWORD Stack)
             break;
         }
 
-        /* Get Current Process ID (Get PSP Address) */
+        /* Internal - Get Current Process ID (Get PSP Address) */
         case 0x51:
         {
+            /*
+             * Identical to the documented AH=62h.
+             * See Ralf Brown: http://www.ctyme.com/intr/rb-2982.htm
+             * for more information.
+             */
             setBX(CurrentPsp);
             break;
         }
@@ -2391,6 +2396,24 @@ VOID DosInt21h(LPWORD Stack)
             break;
         }
 
+        /* Get Current PSP Address */
+        case 0x62:
+        {
+            /*
+             * Identical to the undocumented AH=51h.
+             * See Ralf Brown: http://www.ctyme.com/intr/rb-3140.htm
+             * for more information.
+             */
+            setAH(0x51); // Call the internal function.
+            /*
+             * Instead of calling ourselves really recursively as in:
+             * DosInt21h(Stack);
+             * prefer resetting the CF flag to let the BOP repeat.
+             */
+            setCF(1);
+            break;
+        }
+
         /* Unsupported */
         default:
         {