Modified harddisk firmware to support Apple Oasis' entrypoint:

. for DOSMaster images created with Apple Oasis (Feature #5557).
Ported & added a Win32 build of the a65 assembler (see a65v106_w32.zip for source).

AppleWin/firmware/HDD/build.bat

@@ -1,4 +1,4 @@
-a65 -b -l HDDRVR.A65 >hddrvr.lst
+a65_w32 -b -l HDDRVR.A65 >hddrvr.lst
 @del HDDRVR.BIN
 rename 6502.bin HDDRVR.BIN
 copy HDDRVR.BIN ..\..\resource

AppleWin/firmware/HDD/hddrvr.a65

@@ -3,7 +3,7 @@
 ;Copyright (C) 1994-1996, Michael O'Brien
 ;Copyright (C) 1999-2001, Oliver Schmidt
 ;Copyright (C) 2002-2005, Tom Charlesworth
-;Copyright (C) 2006-2007, Tom Charlesworth, Michael Pohoreski
+;Copyright (C) 2006-2012, Tom Charlesworth, Michael Pohoreski
 ;
 ;AppleWin is free software; you can redistribute it and/or modify
 ;it under the terms of the GNU General Public License as published by
@@ -27,7 +27,8 @@
 
 ; Modified by Tom Charlesworth:
 ; . Fixed so it can be assembled by a65 v1.06
-; . Fixed so that ProDOS entrypoint is $c70a
+; . Fixed so that ProDOS entrypoint is $c70a (26 Dev 2007) (Bug #12723)
+; . Modified to support Apple Oasis' entrypoint: $c761 (8 Sept 2012) (Feature #5557)
 ; . TO DO: Make code relocatable
 ;
 
@@ -102,19 +103,33 @@ noerr0
 ; no image ready, boot diskette image instead
  jmp slot6
 
- ; 24 unused bytes
+;======================================
+; 24 unused bytes
 
 *= $c746	; org $c746
 
-Entrypont_C746	; Old f/w 'cmdproc' entrypoint
+Entrypoint_C746	; Old f/w 'cmdproc' entrypoint
 				; Keep this for any DOSMaster HDD images created with old AppleWin HDD f/w.
 				; DOSMaster hardcodes the entrypoint addr into its bootstrapping code:
 				; - So DOSMaster images are tied to the HDD's controller's f/w
  sec
  bcs Entrypoint
+
+
+;======================================
+; 23 unused bytes
  
- ;
- 
+*= $c761	; org $c761
+
+Entrypoint_C761	; Apple Oasis HDD controller entrypoint
+				; Keep this for any DOSMaster HDD images created with Apple Oasis HDD f/w.
+				; DOSMaster hardcodes the entrypoint addr into its bootstrapping code:
+				; - So DOSMaster images are tied to the HDD's controller's f/w
+ sec
+ bcs Entrypoint
+
+;======================================
+
 ; image ready.  Lets boot from it.
 ; we want to load block 1 from s7,d1 to $800 then jump there
 hdboot
@@ -203,7 +218,8 @@ loop2
  tay
  rts
 
-
+;======================================
+; 37 unused bytes
 
 ; $CsFE = status bits (BAP p7-14)
 ;  7 = medium is removable

AppleWin/source/CPU.cpp

@@ -282,10 +282,43 @@ void CaptureCOUT(void)
 
 //===========================================================================
 
+//#define DBG_HDD_ENTRYPOINT
+#if defined(_DEBUG) && defined(DBG_HDD_ENTRYPOINT)
+// Output a debug msg whenever the HDD f/w is called or jump to.
+static void DebugHddEntrypoint(const USHORT PC)
+{
+	static bool bOldPCAtC7xx = false;
+	static WORD OldPC = 0;
+	static UINT Count = 0;
+
+	if ((PC >> 8) == 0xC7)
+	{
+		if (!bOldPCAtC7xx /*&& PC != 0xc70a*/)
+		{
+			Count++;
+			char szDebug[100];
+			sprintf(szDebug, "HDD Entrypoint: $%04X\n", PC);
+			OutputDebugString(szDebug);
+		}
+
+		bOldPCAtC7xx = true;
+	}
+	else
+	{
+		bOldPCAtC7xx = false;
+	}
+	OldPC = PC;
+}
+#endif
+
 static __forceinline int Fetch(BYTE& iOpcode, ULONG uExecutedCycles)
 {
 	const USHORT PC = regs.pc;
 
+#if defined(_DEBUG) && defined(DBG_HDD_ENTRYPOINT)
+	DebugHddEntrypoint(PC);
+#endif
+
 	iOpcode = ((PC & 0xF000) == 0xC000)
 	    ? IORead[(PC>>4) & 0xFF](PC,PC,0,0,uExecutedCycles)	// Fetch opcode from I/O memory, but params are still from mem[]
 		: *(mem+PC);