From 153b494e6124153fef5c87501cd0c6d90ad86d81 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Sun, 5 Apr 2020 17:03:17 -0700
Subject: [PATCH] CP/M 3 Date Hack

- Hack to allow INTRTC to increment time without destroying the date
---
 Source/CPM3/boot.z80 | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/Source/CPM3/boot.z80 b/Source/CPM3/boot.z80
index b80d7631..53e36f47 100644
--- a/Source/CPM3/boot.z80
+++ b/Source/CPM3/boot.z80
@@ -490,16 +490,21 @@ time$ret:
 
 time$get:
 	; RTC -> cpm date/time in SCB
-	
+
 	; read time from RTC
 	ld	b,020h		; HBIOS func: get time
 	ld	hl,tim$buf	; time buffer
 	rst	08		; do it
 	ret	nz		; bail out on error
 	
+	ld	a,(datehack)
+	or	a
+	jr	nz,time$get1
+	
 	; convert yymmss in time buffer -> cpm3 epoch date offset
 	call	date2cpm	; time buf (yr, mon, day) -> SCB (@date)
 
+time$get1:
 	; set time fields in SCB
 	ld	a,(tim$hr)	; get hour from time buf
 	ld	(@hour),a	; ... and put in SCB
@@ -514,7 +519,23 @@ time$set:
 	; CPM date/time in SCB -> RTC
 	
 	; convert CPM3 epoch date offset in SCB -> yymmss in time buffer
-	call	cpm2date	; SCB (@date) -> time buf (yr, mon, day)
+	;call	cpm2date	; SCB (@date) -> time buf (yr, mon, day)
+
+	; this is a temporary hack!!!
+	; since we cannot actually set the date on the RTC, we
+	; just read the current RTC date and use that so that we
+	; don't clobber a potentially good date.
+	; read time from RTC
+	ld	b,020h		; HBIOS func: get time
+	ld	hl,tim$buf	; time buffer
+	rst	08		; do it
+	ret	nz		; bail out on error
+	;
+	; now we set a hack active flag so that future time$get
+	; calls do not update the date field in the SCB
+	;
+	ld	a,0FFh		; true value
+	ld	(datehack),a	; save it
 	
 	; copy CPM3 time values from SCB -> time buffer
 	ld	a,(@hour)	; get hour from SCB
@@ -629,6 +650,8 @@ tim$hr		db	01h
 tim$min		db	02h
 tim$sec		db	03h
 
+datehack	db	00h
+
 open:
 	ld	c,15
 	jp	bdos