From 953dd700520f6a983e083f1284394038db1d3785 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Mon, 22 Feb 2021 18:49:31 -0800
Subject: [PATCH] Z180 Invalid Opcode Tweaks

Thanks and credit to Phillip Stevens for his significant contributions to this enhancement.
---
 Doc/ChangeLog.txt      |  2 ++
 Source/HBIOS/hbios.asm | 24 ++++++++----------------
 Source/ver.inc         |  2 +-
 Source/ver.lib         |  2 +-
 4 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/Doc/ChangeLog.txt b/Doc/ChangeLog.txt
index b33c735b..947ddb71 100644
--- a/Doc/ChangeLog.txt
+++ b/Doc/ChangeLog.txt
@@ -17,6 +17,8 @@ Version 3.1.1
 - WBW: Support for Z280 w/ native memory and interrupt mode 3
 - WBW: Support for Z280 UART (interrupt driven only in interrupt mode 3)
 - WBW: Add support Z80-512K (watchdog and LED)
+- WBW: Add support for ZZ80MB address map
+- PLS: Add support for Z180 invalid opcode trap
 
 Version 3.1
 -----------
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index c5bc7e68..3e7e7b2b 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -2958,13 +2958,16 @@ SYS_RESCOLD:
 ; HOOK CALLED WHEN A USERLAND RESET IS INVOKED, TYPICALLY VIA A JUMP
 ; TO LOGICAL CPU ADDRESS $0000
 ;
+; CREDIT TO PHILLIP STEVENS FOR SUGGESTING AND SIGNIFICANT CONTRIBUTIONS
+; TO THE Z180 INVALID OPCODE TRAP ENHANCEMENT.
+;
 SYS_RESUSER:
 ;
 #IF (CPUFAM == CPU_Z180)
 ;
 	IN0	A,(Z180_ITC)		; GET ITC REGISTER
-	BIT	7,A			; TRAP BIT SET?
-	JR	Z,SYS_RESUSER9		; IF NOT, SKIP AHEAD
+	XOR	$80			; PRECLEAR TRAP BIT
+	RET	M			; IF TRAP BIT NOT SET, DONE
 ;
 	; HANDLE INVALID OPCODE
 	DEC	HL			; BACK UP TO OPCODE START
@@ -2977,8 +2980,8 @@ SYS_RESUSER1:
 	OUT0	(Z180_ITC),A		; SAVE IT
 ;
 	CALL	PRTSTRD			; PRINT ERROR TAG
-	.TEXT	"\r\n\r\n+++ BAD OPCODE @$"
-	CALL	PRTHEXWORDHL		; PRINT ADDRESS
+	.TEXT	"\r\n\r\n+++ INVALID Z180 OPCODE @$"
+	CALL	PRTHEXWORDHL		; PRINT OPCODE ADDRESS
 	PRTS("H:$")			; FORMATTING
 ;
 	LD	B,8			; SHOW 8 BYTES
@@ -2995,20 +2998,9 @@ SYS_RESUSER2:
 	POP	BC			; RECOVER BC
 	INC	HL			; NEXT BYTE
 	DJNZ	SYS_RESUSER2		; LOOP TIL DONE
-	CALL	NEWLINE			; FORMATTING
+	JP	NEWLINE			; FORMATTING & EXIT
 ;
 #ENDIF
-;
-SYS_RESUSER9:
-	;; NOTIFY USER
-	;CALL	PRTSTRD
-	;.TEXT	"\r\n*** USER RESET ***\r\n$"
-;
-	;; EXIT VIA USER RESET VECTOR (IF SET)
-	;LD	HL,(HB_RESVEC)		; GET USER RESET VECTOR
-	;LD	A,H			; CHECK IF IT
-	;OR	L			; ... HAS BEEN SET
-	;JP	Z,SYS_RESWARM		; IF NOT, JUST WARM START
 ;
 	RET				; ELSE RETURN WITH USER RESET VECTOR IN HL
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index 0874d9c4..8529eb98 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,4 +2,4 @@
 #DEFINE	RMN	1
 #DEFINE	RUP	1
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.1.1-pre.52"
+#DEFINE BIOSVER	"3.1.1-pre.53"
diff --git a/Source/ver.lib b/Source/ver.lib
index c0a496e9..9c610ce4 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	1
 rup	equ	1
 rtp	equ	0
 biosver	macro
-	db	"3.1.1-pre.52"
+	db	"3.1.1-pre.53"
 	endm