Add Zero Option to TIMER Application

@MartinR-UK enhanced TIMER to allow zeroing the seconds counter.

Co-Authored-By: MartinR <174514335+MartinR-UK@users.noreply.github.com>

Doc/ChangeLog.txt

@@ -28,6 +28,7 @@ Version 3.6
 - WBW: Updated Cowgol disk image with latest COWFIX.COM from Ladislau Szilagyi
 - WBW: Preliminary support for S100 Computers Z80 CPU
 - HJB: Added MSX platform
+- M?R: Update Timer app with "zero" option
 
 Version 3.5.1
 -------------

RELEASE_NOTES.md

@@ -8,10 +8,27 @@ release of RomWBW.
 - **Please** review the "Upgrading" Section of the RomWBW User Guide.
 
 - The RomWBW ROM and the RomWBW disk images are intended to be a
-  matched set.  After upgrading your ROM, it is important to update
-  the OS boot tracks of your disks as well as the RomWBW-specific
-  applications.  This is discussed in the "Upgrading" section of the
-  RomWBW User Guide.
+  matched set.  After upgrading your ROM, you need to update your
+  boot disk media by doing one of the following:
+  
+  - Write a new disk image (typically hd1k_combo.img) onto your
+    disk media (will overwrite existing data/files).
+  - Update the boot tracks of the bootable OS images as described in
+    the RomWBW User Guid.
+
+## Version 3.6
+
+### Upgrade Notes
+
+- The FZ80 (S100 FPGA Z80) platform has been renamed to SZ80 (S100 Z80)
+  and has two configurations.  SZ80_std is for the generic S100
+  Z80 CPU.  SZ80_fpga is for the FPGA Z80 SBC.
+
+### New Features
+
+### New Hardware Support
+
+- Support for MSX systems.
 
 ## Version 3.5.1
 
@@ -94,7 +111,6 @@ This is a patch release of v3.5.
 - Enhancements to ASSIGN command to automatically assign drives
   (Mark Pruden).
 
-
 ### New Hardware Support
 
 - NABU w/ RomWBW Option Board.

ReadMe.md

@@ -7,7 +7,7 @@
 **RomWBW Introduction** \
 Version 3.6 \
 Wayne Warthen  ([wwarthen@gmail.com](mailto:wwarthen@gmail.com)) \
-24 Sep 2025
+26 Sep 2025
 
 # Overview
 

ReadMe.txt

@@ -1,6 +1,6 @@
 RomWBW Introduction
 Wayne Warthen (wwarthen@gmail.com)
-24 Sep 2025
+26 Sep 2025
 
 
 

Source/Apps/timer/timer.asm

@@ -1,17 +1,21 @@
 ;===============================================================================
 ; TIMER - Display system timer value
-; Version 1.31 24-July-2024
+; Version 1.4 25-September-2025
 ;===============================================================================
 ;
 ;	Author:  Wayne Warthen (wwarthen@gmail.com)
-;	Updated: MartinR (July 2024) - A user of uppercase mnemonics
+;	Updated: MartinR (September 2025) - A user of uppercase Z80 mnemonics
+;_______________________________________________________________________________
+;
+; This source code would benefit from a complete resstructuring to aid clarity.
 ;_______________________________________________________________________________
 ;
 ; Usage:
-;   TIMER [/C] [/?]
-;     ex: TIMER		(display current timer value)
-;         TIMER /?	(display version and usage)
-;         TIMER /C	(display timer value continuously)
+;   TIMER [/C] [Z] [/?]
+;     ex: TIMER		Display current timer value
+;         TIMER /?	Display version and usage
+;         TIMER /C	Display timer value continuously
+;	  TIMER /Z	Set the system timer to zero
 ;
 ; Operation:
 ;   Reads and displays system timer value.
@@ -21,7 +25,7 @@
 ; This source code assembles with TASM V3.2 under Windows-11 using the
 ; following command line:
 ;	tasm -80 -g3 -l TIMER.ASM TIMER.COM
-;	ie: Z80 CPU; output format 'binary' named .COM (rather than .OBJ)
+;	ie: Z80 CPU, output format 'binary' named .COM (rather than .OBJ)
 ;	and includes a symbol table as part of the listing file.
 ;_______________________________________________________________________________
 ;
@@ -31,6 +35,7 @@
 ;   2019-11-08 [WBW] Add seconds support
 ;   2024-06-30 [MR ] Display values in decimal rather than hexadecimal
 ;   2024-07-24 [MR ] Also display value in Hours-Mins-Secs format
+;   2025-09-25 [MR ] Add the option to set the system timer back to zero
 ;_______________________________________________________________________________
 ;
 ; Includes binary-to-decimal subroutine by Alwin Henseler
@@ -63,14 +68,14 @@ BF_SYSGETSECS	.EQU	$D1		; SECONDS subfunction
 BF_SYSSETSECS	.EQU	$D1		; SECONDS subfunction
 ;
 ;ASCII Control Characters
-LF		.EQU 	00AH		; Line Feed
-CR		.EQU 	00DH		; Carriage Return
+LF		.EQU 	$0A		; Line Feed
+CR		.EQU 	$0D		; Carriage Return
 ;
 ;===============================================================================
 ; Code Section
 ;===============================================================================
 ;
-	.ORG	$100
+	.ORG	$0100
 ;
 	; setup stack (save old value)
 	LD	(STKSAV),SP		; save stack
@@ -98,7 +103,7 @@ INIT:
 	CALL	PRTSTR			; print it
 ;
 	CALL	IDBIO			; identify active BIOS
-	CP	1				; check for HBIOS
+	CP	1			; check for HBIOS
 	JP	NZ,ERRBIO		; handle BIOS error
 ;
 	LD	A,RMJ << 4 | RMN	; expected HBIOS ver
@@ -282,10 +287,12 @@ OPTION:
 	RET	Z			; done if so
 	CP	' '			; blank?
 	RET	Z			; done if so
-	CP	'?'			; is it a '?'?
-	JP	Z,USAGE			; yes, display usage
-	CP	'C'			; is it a 'C', continuous?
-	JP	Z,SETCONT		; yes, set continuous display
+	CP	'?'			; Is it a '?' for 'help' command?
+	JP	Z,USAGE			; Yes, display usage
+	CP	'C'			; Is it a 'C' for 'continuous' command?
+	JP	Z,SETCONT		; Yes, set continuous display mode
+	CP	'Z'			; Is it a 'Z' for 'zero timer' command?
+	JR	Z,ZEROISE		; Set the timer to zero
 	JP	ERRPRM			; anything else is an error
 ;
 USAGE:
@@ -293,9 +300,21 @@ USAGE:
 ;
 SETCONT:
 ;
-	OR	$FF			; SET A TO TRUE
-	LD	(CONT),A		; AND SET CONTINUOUS FLAG
-	JR	OPTION			; CHECK FOR MORE OPTION LETTERS
+	OR	$FF			; Set A to true
+	LD	(CONT),A		; and set CONT(inous) flag
+	JR	OPTION			; Check for any more option letters.
+;
+ZEROISE:
+;
+	LD	DE,MSGZERO		; Confirm resetting system timer to zero
+	CALL	PRTSTR	
+;
+	LD	B,BF_SYSSET		; HBIOS SYSSET function
+	LD	C,BF_SYSSETSECS		; SETSECS subfunction
+	LD	DE,$0000		; set seconds value
+	LD	HL,$0000		; ... to zero
+	RST	08			; Call HBIOS, DE:HL := seconds value
+	JP	EXIT			; Done - so exit back to CCP
 ;
 ; Identify active BIOS.  RomWBW HBIOS=1, UNA UBIOS=2, else 0
 ;
@@ -772,14 +791,16 @@ LOOPDIV1:
 ; Messages Section
 ;===============================================================================
 
-MSGBAN	.DB	"TIMER v1.31, 24-Jul-2024",CR,LF
+MSGBAN	.DB	"TIMER v1.4, 25-Sep-2025",CR,LF
 	.DB	"Copyright (C) 2019, Wayne Warthen, GNU GPL v3",CR,LF
-	.DB	"Updated by MartinR 2024",0
-MSGUSE	.DB	"Usage: TIMER [/C] [/?]",CR,LF
-	.DB	"  ex. TIMER           (display current timer value)",CR,LF
-	.DB	"      TIMER /?        (display version and usage)",CR,LF
-	.DB	"      TIMER /C        (display timer value continuously)",0
+	.DB	"Updated by MartinR 2024 & 2025",CR,LF,0
+MSGUSE	.DB	"Usage: TIMER [/C] [Z] [/?]",CR,LF
+	.DB	"  ex. TIMER           Display current timer value",CR,LF
+	.DB	"      TIMER /?        Display version and usage",CR,LF
+	.DB	"      TIMER /C        Display timer value continuously",CR,LF
+	.DB	"      TIMER /Z        Set the timer to zero",0
 MSGPRM	.DB	"Parameter error (TIMER /? for usage)",0
+MSGZERO	.DB	"Setting system timer to zero",0
 MSGBIO	.DB	"Incompatible BIOS or version, "
 	.DB	"HBIOS v", '0' + rmj, ".", '0' + rmn, " required",0
 STRTICK	.DB	" Ticks   ",0

Source/Doc/Applications.md

@@ -2487,6 +2487,7 @@ displays the value of the counter.
 `TIMER`
 `TIMER /?`
 `TIMER /C`
+`TIMER /Z`
 
 #### Usage
 
@@ -2494,9 +2495,11 @@ Use `TIMER` to display the current value of the counter.
 
 Use `TIMER /C` to display the value of the counter continuously.
 
+Use `TIMER /Z` to zero the seconds counter.
+
 The display of the counter will be something like this:
 
-`13426 Ticks     268.52 Seconds`
+`2859 Ticks   24.18 Seconds   0:00:24.18 HH:MM:SS`
 
 The first number is the total number of ticks since system startup, where
 there are 50 ticks per second. The second number is the total number of
@@ -2504,15 +2507,18 @@ seconds since system startup. Numbers are displayed in decimal format.
 
 #### Notes
 
-The seconds value is displayed with a fractional value which is not a
-an actual fraction, but rather the number of ticks past the seconds
-rollover.  All values are in hex.
+Not all systems will have a system timer.  In this case, the
+`TIMER` command will output 0 for both ticks and seconds and never
+increment.
 
-The primary use of the `TIMER` application is to test the system
-timer functionality of your system.
+The resolution of the timer is determined by the system timer
+frequency which is typically 50Hz.  This means that the seconds
+fraction will increment 0.02 seconds with each timer tick.
 
-In theory, you could capture the value before and after some process
-you want to time.
+The primary use of the `TIMER` application is to test the system
+timer functionality of your system.  However, it can be used to
+capture the value before and after some process you want to measure
+elapsed runtime.
 
 #### Etymology