From: Michael Brown <mcb30@ipxe.org>
Date: Thu, 28 Apr 2011 12:05:40 +0000 (+0100)
Subject: [int13] Catch INT 13,4b when no explicit drive number is present
X-Git-Tag: v1.20.1~2139
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=62c963516612103c965f7b4789faf63753ca77a4;p=thirdparty%2Fipxe.git

[int13] Catch INT 13,4b when no explicit drive number is present

This allows older versions of ELTORITO.SYS (such as the version found
on the FreeDOS installation CD-ROM) to use iPXE's emulated CD-ROM
drive.

Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/arch/i386/interface/pcbios/int13.c b/src/arch/i386/interface/pcbios/int13.c
index 93d01088f..b099958c6 100644
--- a/src/arch/i386/interface/pcbios/int13.c
+++ b/src/arch/i386/interface/pcbios/int13.c
@@ -1187,12 +1187,17 @@ static __asmcall void int13 ( struct i386_all_regs *ix86 ) {
 					bios_drive, int13->drive );
 				ix86->regs.dl = int13->drive;
 				return;
+			} else if ( ( ( bios_drive & 0x7f ) == 0x7f ) &&
+				    ( command == INT13_CDROM_STATUS_TERMINATE )
+				    && int13->is_cdrom ) {
+				/* Catch non-drive-specific CD-ROM calls */
+			} else {
+				continue;
 			}
-			continue;
 		}
 		
 		DBGC2 ( int13, "INT13,%02x (%02x): ",
-			ix86->regs.ah, int13->drive );
+			ix86->regs.ah, bios_drive );
 
 		switch ( command ) {
 		case INT13_RESET: