Handle lack of RTC better

DSRTC driver now correctly returns an error if there is no RTC present.

Doc/ChangeLog.txt

@@ -3,7 +3,9 @@ Version 3.0.1
 - WBW: Increase XModem timeout waiting for host to start sending
 - WBW: Update TMS driver to dynamically increase Z180 I/O W/S inside driver
 - MJS: Update CLRDIR for CP/M 3 compatibility
-- WBW: Corrected cursor on/off esc sequence in pre-configured ZDE.
+- WBW: Corrected cursor on/off esc sequence in pre-configured ZDE
+- WBW: Fix automatic CRT console switching under CP/M 3 and ZPM3
+- WBW: DSRTC driver now correctly returns an error if there is no RTC present
 
 Version 3.0.0
 -------------

Source/CPM3/boot.z80

@@ -495,6 +495,7 @@ time$get:
 	ld	b,020h		; HBIOS func: get time
 	ld	hl,tim$buf	; time buffer
 	rst	08		; do it
+	ret	nz		; bail out on error
 	
 	; convert yymmss in time buffer -> cpm3 epoch date offset
 	call	date2cpm	; time buf (yr, mon, day) -> SCB (@date)

Source/HBIOS/dsrtc.asm

@@ -236,6 +236,9 @@ DSRTC_SETBLK:
 ; 24 HOUR TIME FORMAT IS ASSUMED
 ;
 DSRTC_GETTIM:
+	LD	A,(DSRTC_STAT)		; GET DEVICE STATUS
+	OR	A			; SET FLAGS
+	RET	NZ			; BAIL OUT ON ERROR
 ;
 	PUSH	HL			; SAVE ADR OF OUTPUT BUF
 ;
@@ -272,6 +275,9 @@ DSRTC_GETTIM:
 ; 24 HOUR TIME FORMAT IS ASSUMED
 ;
 DSRTC_SETTIM:
+	LD	A,(DSRTC_STAT)		; GET DEVICE STATUS
+	OR	A			; SET FLAGS
+	RET	NZ			; BAIL OUT ON ERROR
 ;
 	; COPY INCOMING TIME DATA TO OUR TIME BUFFER
 	LD	A,(HB_INVBNK)		; COPY FROM CURRENT USER BANK
@@ -303,6 +309,9 @@ DSRTC_SETTIM:
 ;   E: VALUE (OUTPUT)
 ;
 DSRTC_GETBYT:
+	LD	A,(DSRTC_STAT)		; GET DEVICE STATUS
+	OR	A			; SET FLAGS
+	RET	NZ			; BAIL OUT ON ERROR
 	LD	A,C			; INDEX
 	SLA	A			; SHIFT TO INDEX BITS
 	ADD	A,$C1			; CMD OFFSET
@@ -316,6 +325,9 @@ DSRTC_GETBYT:
 ;   E: VALUE
 ;
 DSRTC_SETBYT:
+	LD	A,(DSRTC_STAT)		; GET DEVICE STATUS
+	OR	A			; SET FLAGS
+	RET	NZ			; BAIL OUT ON ERROR
 	LD	A,C			; INDEX
 	SLA	A			; SHIFT TO INDEX BITS
 	ADD	A,$C0			; CMD OFFSET

Source/Images/d_cpm3/u0/ROMWBW.TXT

@@ -1,23 +1,21 @@
 This is a generic CP/M 3 adaptation for RomWBW.
 
-To start CP/M 3, first boot into CP/M 2.2 or ZSystem.  Then
-switch to the drive that contains the CP/M 3 hard disk image
-and run CPMLDR.  You will be prompted for the disk unit
-of the CP/M 3 image.
+There are two ways to launch CP/M 3.  First, you can run the command
+CPMLDR from a CP/M 2.2 or Z-System command line.  Alternatively, you
+boot directly into CP/M 3 by choosing the CP/M 3 disk from the RomWBW
+loader prompt.  The CP/M 3 disk must be bootable in this case.
 
-With the following exceptions, the files in this directory
-came from the CP/M 3 binary distribution on "The Unofficial
-CP/M Web site" at http://www.cpm.z80.de/binary.html.
+With the following exceptions, the files in this directory came from
+the CP/M 3 binary distribution on "The Unofficial CP/M Web site" at
+http://www.cpm.z80.de/binary.html.
 
-As documented in the "README.1ST" file, the included
-files have been patched with all applicable DRI patches
-per CPM3FIX.PAT.
+As documented in the "README.1ST" file, the included files have been
+patched with all applicable DRI patches per CPM3FIX.PAT.
 
 In addition, the following have been added:
 
-- INITDIR.COM was not included.  The copy included is the
-  original DRI distribution, with both patches installed.
+- INITDIR.COM was not included.  The copy included is the original
+  DRI distribution, with both patches installed.
 
-- ZSID.COM is the original DRI ZSID distribution, but
-  patched to use RST 6 instead of RST 7 to avoid conflicting
-  with mode 1 interrupts.
+- ZSID.COM is the original DRI ZSID distribution, but patched to use 
+  RST 6 instead of RST 7 to avoid conflicting with mode 1 interrupts. 

Source/Images/d_zpm3/u0/ROMWBW.TXT

@@ -1,32 +1,28 @@
 This is a generic ZPM3 adaptation for RomWBW.
 
-To start ZPM3, first boot into CP/M 2.2 or ZSystem.  Then
-switch to the drive that contains the ZPM3 hard disk image
-and run CPMLDR.  You will be prompted for the disk unit
-of the ZPM3 image.
+There are two ways to launch ZPM3.  First, you can run the command
+CPMLDR from a CP/M 2.2 or Z-System command line.  Alternatively, you
+boot directly into ZPM3 by choosing the ZPM3 disk from the RomWBW
+loader prompt.  The ZPM3 disk must be bootable in this case.
 
-You may notice that there is a ZPMLDR application on the
-hard disk image.  This application is equivalent to CPMLDR,
-but it has some issues with the number of drives that
-RomWBW supports.  So, as indicated above, use CPMLDR to
-launch ZPM3.
+You may notice that there is a ZPMLDR application on the hard disk
+image.  This application is equivalent to CPMLDR, but it has some
+issues with the number of drives that RomWBW supports.  So, as
+indicated above, use CPMLDR to launch ZPM3.
 
-I have not found a way to make ZPM3 start up with any drive
-other than A: as the system drive.  So, during the load
-process, the boot drive and drive A: are "swapped" so that
-the boot drive is always drive A:.  Use the ASSIGN
-command after starting ZPM3 to see how the drives get
-mapped.
+I have not found a way to make ZPM3 start up with any drive other
+than A: as the system drive.  So, during the load process, the boot
+drive and drive A: are "swapped" so that the boot drive is always
+drive A:.  Use the ASSIGN command after starting ZPM3 to see how the
+drives get mapped.
 
-Per ZPM3 standard, files are distributed across different
-user areas depending on their usage.  Normal applications
-are in user 15.  Help files in user 10.  Configuration 
-files in user 14.
+Per ZPM3 standard, files are distributed across different user areas
+depending on their usage.  Normal applications are in user 15.  Help
+files in user 10.  Configuration files in user 14.
 
-In addition to the applications provided in the ZPM3
-distributio, the normal CP/M 3 files are included in user
-area 15.  A few typical ZCPR utility programs are also included
-in user area 15:
+In addition to the applications provided in the ZPM3 distributio, the
+normal CP/M 3 files are included in user area 15.  A few typical ZCPR
+utility programs are also included in user area 15:
 
  - ALIAS
  - ARUNZ
@@ -47,5 +43,5 @@ in user area 15:
 
 It is a bit confusing, but the ZPM3 system file is called CPM3.SYS.
 This is the ZPM3 default configuration and I guess it is done this
-way to maximize compatibility with CP/M 3.  You will notice that
-the startup banner will indicate ZPM3.
+way to maximize compatibility with CP/M 3.  You will notice that the
+startup banner will indicate ZPM3.