From f0dd8184d894eb99f27256a24d87ba5a040fc520 Mon Sep 17 00:00:00 2001
From: "Howard M. Harte" <hharte@magicandroidapps.com>
Date: Mon, 15 Feb 2021 11:01:07 -0800
Subject: [PATCH] AltairZ80: Fix North Star MDS-AD for NSDOS

The "Window" bit was getting cleared too late, causing the "next" sector
to be written under North Star DOS.  Due to differences between CP/M and
North Star disk access routines, this was not an issue under CP/M.

Test: Verify that North Star DOS and CP/M can format, copy and verify an
entire disk.

North Star Disk Operating System, Version 2.1.1, at  100
+GO DT 2
SINGLE(S) OR DOUBLE(D) DENSITY TEST? D
BOTH SIDES (Y OR N)? Y
LOAD DISKETTE THEN PRESS RETURN TO BEGIN TEST
PASS COMPLETE
PASS COMPLETE
PASS COMPLETE
PASS COMPLETE
PASS COMPLETE
CONTROL-C STOP
+GO CD 1 2
COPY BOTH SIDES (Y OR N)? Y
LOAD DISKETTES AND PRESS RETURN WHEN READY.
COPY COMPLETED.
+GO CK 1
DISKETTE CHECK, VERSION 1
CHECK CODE: 46513
+GO CK 2
DISKETTE CHECK, VERSION 1
CHECK CODE: 46513
+
---
 AltairZ80/s100_mdsad.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/AltairZ80/s100_mdsad.c b/AltairZ80/s100_mdsad.c
index 263c125f..94657d24 100644
--- a/AltairZ80/s100_mdsad.c
+++ b/AltairZ80/s100_mdsad.c
@@ -1,9 +1,7 @@
 /*************************************************************************
  *                                                                       *
- * $Id: s100_mdsad.c 1995 2008-07-15 03:59:13Z hharte $                  *
- *                                                                       *
- * Copyright (c) 2007-2008 Howard M. Harte.                              *
- * http://www.hartetec.com                                               *
+ * Copyright (c) 2007-2021 Howard M. Harte.                              *
+ * https://github.com/hharte                                             *
  *                                                                       *
  * Permission is hereby granted, free of charge, to any person obtaining *
  * a copy of this software and associated documentation files (the       *
@@ -35,9 +33,6 @@
  *     Northstar MDS-AD Disk Controller module for SIMH                  *
  * Only Double-Density is supported for now.                             *
  *                                                                       *
- * Environment:                                                          *
- *     User mode only                                                    *
- *                                                                       *
  *************************************************************************/
 
 /*#define DBG_MSG*/
@@ -479,7 +474,7 @@ static uint8 MDSAD_Read(const uint32 Addr)
                 sdata.raw[mdsad_info->datacount] = Addr & 0xFF;
 
             if(mdsad_info->datacount == (MDSAD_RAW_LEN - 1)) {
-                sim_debug(WR_DATA_MSG, &mdsad_dev, "MDSAD: " ADDRESS_FORMAT
+                sim_debug(WR_DATA_DETAIL_MSG, &mdsad_dev, "MDSAD: " ADDRESS_FORMAT
                           " Write Complete\n", PCX);
 
                 if ((pDrive->uptr == NULL) || (pDrive->uptr->fileref == NULL)) {
@@ -586,7 +581,6 @@ static uint8 MDSAD_Read(const uint32 Addr)
                         case 10:
                         {
                             mdsad_info->com_status.sf = 1;
-                            mdsad_info->a_status.wi = 0;
                             mdsad_info->a_status.re = 0;
                             mdsad_info->a_status.bd = 0;
                             pDrive->sector_wait_count = 0;
@@ -603,6 +597,7 @@ static uint8 MDSAD_Read(const uint32 Addr)
                             mdsad_info->a_status.wi = 1;
                             break;
                         case 3:
+                            mdsad_info->a_status.wi = 0;
                             mdsad_info->a_status.re = 1;
                             mdsad_info->a_status.bd = 1;
                             break;
@@ -770,7 +765,7 @@ static uint8 MDSAD_Read(const uint32 Addr)
                             PCX, sec_offset, mdsad_info->datacount, cData));
                     } else { /* checksum */
                         cData = checksum;
-                        sim_debug(RD_DATA_MSG, &mdsad_dev, "MDSAD: " ADDRESS_FORMAT
+                        sim_debug(RD_DATA_DETAIL_MSG, &mdsad_dev, "MDSAD: " ADDRESS_FORMAT
                                   " READ-DATA: Checksum is: 0x%02x\n",
                                   PCX, cData);
                     }