From 6dfe1d9dcf07b6ecaadd8868d0beda3fc7d32b0f Mon Sep 17 00:00:00 2001
From: Peter Veenstra <qbix79@users.sourceforge.net>
Date: Thu, 1 Sep 2011 12:19:52 +0000
Subject: [PATCH] Call int 0xe when resetting a disk. Fixes a keydisk
 workaround algorithm. (thanks ripsaw)

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3751
---
 include/callback.h     |  2 +-
 src/cpu/callback.cpp   | 13 ++++++++++++-
 src/ints/bios_disk.cpp |  4 +++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/callback.h b/include/callback.h
index 382efc56..ff7ebfac 100644
--- a/include/callback.h
+++ b/include/callback.h
@@ -30,7 +30,7 @@ extern CallBack_Handler CallBack_Handlers[];
 enum { CB_RETN,CB_RETF,CB_RETF8,CB_IRET,CB_IRETD,CB_IRET_STI,CB_IRET_EOI_PIC1,
 		CB_IRQ0,CB_IRQ1,CB_IRQ9,CB_IRQ12,CB_IRQ12_RET,CB_IRQ6_PCJR,CB_MOUSE,
 		CB_INT29,CB_INT16,CB_HOOKABLE,CB_TDE_IRET,CB_IPXESR,CB_IPXESR_RET,
-		CB_INT21 };
+		CB_INT21,CB_INT13 };
 
 #define CB_MAX		128
 #define CB_SIZE		32
diff --git a/src/cpu/callback.cpp b/src/cpu/callback.cpp
index 0c3f3c25..31761e00 100644
--- a/src/cpu/callback.cpp
+++ b/src/cpu/callback.cpp
@@ -433,7 +433,18 @@ Bitu CALLBACK_SetupExtra(Bitu callback, Bitu type, PhysPt physAddress, bool use_
 		phys_writeb(physAddress+0x09,(Bit8u)0x59);		// pop cx
 		phys_writeb(physAddress+0x0A,(Bit8u)0xCF);		//An IRET Instruction
 		return (use_cb?15:11);
-
+	case CB_INT13:
+		phys_writeb(physAddress+0x00,(Bit8u)0xFB);		//STI
+		if (use_cb) {
+			phys_writeb(physAddress+0x01,(Bit8u)0xFE);	//GRP 4
+			phys_writeb(physAddress+0x02,(Bit8u)0x38);	//Extra Callback instruction
+			phys_writew(physAddress+0x03,(Bit16u)callback);	//The immediate word
+			physAddress+=4;
+		}
+		phys_writeb(physAddress+0x01,(Bit8u)0xCF);		//An IRET Instruction
+		phys_writew(physAddress+0x02,(Bit16u)0x0ECD);		// int 0e
+		phys_writeb(physAddress+0x04,(Bit8u)0xCF);		//An IRET Instruction
+		return (use_cb?9:5);
 	default:
 		E_Exit("CALLBACK:Setup:Illegal type %d",type);
 	}
diff --git a/src/ints/bios_disk.cpp b/src/ints/bios_disk.cpp
index a5514467..f3486045 100644
--- a/src/ints/bios_disk.cpp
+++ b/src/ints/bios_disk.cpp
@@ -333,12 +333,14 @@ static Bitu INT13_DiskHandler(void) {
 				if ((machine==MCH_CGA) || (machine==MCH_PCJR)) {
 					/* those bioses call floppy drive reset for invalid drive values */
 					if (((imageDiskList[0]) && (imageDiskList[0]->active)) || ((imageDiskList[1]) && (imageDiskList[1]->active))) {
+						if (reg_dl<0x80) reg_ip++;
 						last_status = 0x00;
 						CALLBACK_SCF(false);
 					}
 				}
 				return CBRET_NONE;
 			}
+			if (reg_dl<0x80) reg_ip++;
 			last_status = 0x00;
 			CALLBACK_SCF(false);
 		}
@@ -500,7 +502,7 @@ static Bitu INT13_DiskHandler(void) {
 void BIOS_SetupDisks(void) {
 /* TODO Start the time correctly */
 	call_int13=CALLBACK_Allocate();	
-	CALLBACK_Setup(call_int13,&INT13_DiskHandler,CB_IRET,"Int 13 Bios disk");
+	CALLBACK_Setup(call_int13,&INT13_DiskHandler,CB_INT13,"Int 13 Bios disk");
 	RealSetVec(0x13,CALLBACK_RealPointer(call_int13));
 	int i;
 	for(i=0;i<4;i++) {