From af8385fba868a5a31a2b6c6285ec6747b4ecb211 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Wed, 15 Nov 2023 12:48:55 -0800
Subject: [PATCH] Fix IM1 Handling for Z180 - Credit to Dylan Hall

- Z180 code failed to initialize interrupt vector registers for IM1 startup
- Updated bad interrupt messaging to avoid interrupt stack overflow
---
 Source/HBIOS/acia.asm  | 18 +++++++++++++++++-
 Source/HBIOS/hbios.asm | 10 ++++++----
 Source/HBIOS/util.asm  | 12 ++++++------
 Source/ver.inc         |  2 +-
 Source/ver.lib         |  2 +-
 5 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/Source/HBIOS/acia.asm b/Source/HBIOS/acia.asm
index 92c9ce90..dd1900a8 100644
--- a/Source/HBIOS/acia.asm
+++ b/Source/HBIOS/acia.asm
@@ -178,10 +178,26 @@ ACIA1_INT:
 ;
 ACIA_INTRCV:
         ; CHECK TO SEE IF SOMETHING IS ACTUALLY THERE
+	CALL	DELAY
         LD      C,(IY+3)                ; CMD/STAT PORT TO C
         IN      A,(C)                   ; GET STATUS
+	LD	B,A
 	AND	$01			; ISOLATE READY BIT
-	RET	Z			; IF NOT READY, RET W/ ZF SET (INT NOT HANDLED)
+	JR	NZ,ACIA_INTRCV1
+;
+#IF FALSE
+	CALL	PC_LT
+	LD	A,B
+	CALL	PRTHEXBYTE
+	INC	C
+	IN	A,(C)
+	CALL	PRTHEXBYTE
+	CALL	PC_GT
+	OR	$FF
+#ENDIF
+;
+	RET
+	
 ;
 ACIA_INTRCV1:
         ; RECEIVE CHARACTER INTO BUFFER
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index fdd3207f..6d76fa0c 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -2057,7 +2057,7 @@ HB_CPU3:
 	LD	A,(CB_CPUMHZ)		; CPU SPEED TO ACCUM AND INIT
 	CALL	DELAY_INIT		; .. SPEED COMPENSATED DELAY
 ;
-#IF (INTMODE == 2)
+#IF ((INTMODE == 2) | ((INTMODE == 1) & (CPUFAM == CPU_Z180)))
 	; SETUP Z80 IVT AND INT MODE 2
 	LD	A,HBX_IVT >> 8		; SETUP HI BYTE OF IVT ADDRESS
 	LD	I,A			; ... AND PLACE IT IN I REGISTER
@@ -2068,7 +2068,9 @@ HB_CPU3:
 	OUT0	(Z180_IL),A		; ... AND PLACE IN Z180 IL REGISTER
   #ENDIF
 
+  #IF (INTMODE == 2)
 	IM	2			; SWITCH TO INT MODE 2
+  #ENDIF
 #ENDIF
 ;
 #IF (INTMODE == 3)
@@ -5418,10 +5420,10 @@ HB_BADINTCNT	.DB	0
 	LD	A,L
 	RRCA
 	RRCA
-	CALL PRTHEXBYTE
-	PRTS("H: $")
-
+	;CALL PRTHEXBYTE
+	;PRTS("H: $")
 	CALL	XREGDMP
+	CALL	NEWLINE
 	;CALL	CONTINUE
 	OR	$FF			; SIGNAL INTERRUPT HANDLED
 	RET
diff --git a/Source/HBIOS/util.asm b/Source/HBIOS/util.asm
index 29e6c532..2496dd52 100644
--- a/Source/HBIOS/util.asm
+++ b/Source/HBIOS/util.asm
@@ -407,8 +407,8 @@ XREGDMP:
 
 	LD	(REGDMP_SP),SP		; SAVE STACK POINTER
 
-	;LD	(RD_STKSAV),SP		; SAVE ORIGINAL STACK POINTER
-	;LD	SP,RD_STACK		; SWITCH TO PRIVATE STACK
+	LD	(RD_STKSAV),SP		; SAVE ORIGINAL STACK POINTER
+	LD	SP,RD_STACK		; SWITCH TO PRIVATE STACK
 
 	PUSH	AF
 	PUSH	BC
@@ -462,7 +462,7 @@ XREGDMP:
 	POP	BC
 	POP	AF
 
-	;LD	SP,(RD_STKSAV)		; BACK TO ORIGINAL STACK FRAME
+	LD	SP,(RD_STKSAV)		; BACK TO ORIGINAL STACK FRAME
 
 	JP	$FFFF			; RETURN, $FFFF IS DYNAMICALLY UPDATED
 REGDMP_RET	.EQU	$-2		; RETURN ADDRESS GOES HERE
@@ -470,9 +470,9 @@ REGDMP_RET	.EQU	$-2		; RETURN ADDRESS GOES HERE
 REGDMP_PC	.DW	0
 REGDMP_SP	.DW	0
 ;
-;RD_STKSAV	.DW	0
-;		.FILL	$FF,16*2	; 16 LEVEL PRIVATE STACK
-;RD_STACK	.EQU	$
+RD_STKSAV	.DW	0
+		.FILL	$FF,16*2	; 16 LEVEL PRIVATE STACK
+RD_STACK	.EQU	$
 ;
 ;
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index d0399649..43938e36 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	4
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.4.0-dev.17"
+#DEFINE BIOSVER	"3.4.0-dev.18"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index ff1e48c9..e9e98711 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	4
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.4.0-dev.17"
+	db	"3.4.0-dev.18"
 	endm