From 8fa14863f8e6701e88e97a7f577b0a9cd826fe78 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Thu, 28 Jan 2021 16:41:33 -0800
Subject: [PATCH] Add System Timer to Z280 IM3

- Z280 counter/timer is now used to implement 50Hz system timer based on CPU oscillator.
- Bug fix in EI <mask> opcodes.
---
 Source/HBIOS/hbios.asm | 101 ++++++++++++++++++++++++++++++++++++++---
 Source/ver.inc         |   2 +-
 Source/ver.lib         |   2 +-
 3 files changed, 97 insertions(+), 8 deletions(-)

diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 3f1623ec..41c1319b 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -118,9 +118,11 @@ MODCNT	.SET	MODCNT + 1
 #ELSE
   #IF (CPUFAM == CPU_Z280)
     #IF (INTMODE == 3)
-; Z280 MODE 3 INTERRUPT HANDLING (INTA & UART ENABLED)
+; Z280 MODE 3 INTERRUPT HANDLING (INTA, C/T 0, & UART RCVR ENABLED)
 #DEFINE	HB_DI		DI
-#DEFINE	HB_EI		.DB	$ED,$F7,$09
+;#DEFINE	HB_DI		.DB	$ED,$77,$7F
+;#DEFINE	HB_EI		EI
+#DEFINE	HB_EI		.DB	$ED,$7F,$0B
     #ELSE
 ; Z280 MODE 1/2 INTERRUPT HANDLING
 #DEFINE	HB_DI		DI
@@ -802,7 +804,7 @@ HBX_INT:	; COMMON INTERRUPT ROUTING CODE
 	POP	HL			; RESTORE HL
 
 	CALL	HBX_RETI		; RETI FOR Z80 PERIPHERALS
-	.DB	$ED,$55			; BACK TO USER LAND
+	.DB	$ED,$55			; RETIL
 ;
 HBX_RETI:	
 	RETI
@@ -1033,7 +1035,7 @@ HB_START:
 	; DISABLE MEMORY REFRESH CYCLES
 	LD	A,$08			; DISABLED
 	OUT	(Z280_RRR),A		; SET REFRESH RATE REGISTER
-	
+;	
 	; RESTORE I/O PAGE TO $00
 	LD	L,$00			; NORMAL I/O REG IS $00
 	LD	C,Z280_IOPR		; REG C POINTS TO I/O PAGE REGISTER
@@ -1593,6 +1595,39 @@ HB_CPU2:
 ;
 #ENDIF
 ;
+#IF (CPUFAM == CPU_Z280)
+;
+  #IF (INTMODE == 3)
+;
+Z280_TC	.EQU	CPUOSC / 4 / 50 / 2	; TIME CONSTANT
+;
+	LD	HL,Z280_TIMINT
+	LD	(Z280_IVT+$16),HL	; Z280 T/C VECTOR
+;
+	; SELECT I/O PAGE $FE
+	LD	L,$FE			; COUNTER/TIMER I/O PAGE
+	LD	C,Z280_IOPR		; REG C POINTS TO I/O PAGE REGISTER
+	.DB	$ED,$6E			; LDCTL	(C),HL
+;
+	LD	A,%10100000		; CONFIG: C, RE, IE
+	OUT	(Z280_CT0_CFG),A	; SET C/T 0
+	LD	HL,Z280_TC		; TIME CONSTANT & COUNTER
+	LD	C,Z280_CT0_TC		; SET C/T 0
+	.DB	$ED,$BF			; OUTW (C),HL
+	LD	C,Z280_CT0_CT		; SET C/T 0
+	.DB	$ED,$BF			; OUTW (C),HL
+	LD	A,%11100000		; CMD: EN, GT
+	OUT	(Z280_CT0_CMDST),A	; SET C/T 0
+;
+	; RESTORE I/O PAGE TO $00
+	LD	L,$00			; NORMAL I/O REG IS $00
+	LD	C,Z280_IOPR		; REG C POINTS TO I/O PAGE REGISTER
+	.DB	$ED,$6E			; LDCTL	(C),HL
+;
+  #ENDIF
+;
+#ENDIF
+;
 ; INITIALIZE HEAP STORAGE
 ;
 	; INITIALIZE POINTERS
@@ -3462,10 +3497,65 @@ HB_IM1PTR	.DW	HB_IVT		; POINTER FOR NEXT IM1 ENTRY
 ;
 #ENDIF
 ;
+;
+;
+#IF (MEMMGR == MM_Z280)
+
+Z280_TIMINT:
+	; DISCARD REASON CODE
+	INC	SP
+	INC	SP
+;
+	; SAVE INCOMING REGISTERS
+	PUSH	AF
+	PUSH	BC
+	PUSH	DE
+	PUSH	HL
+;
+	; CALL PRIMARY TIMER LOGIC
+	CALL	HB_TIMINT
+;
+	; SELECT I/O PAGE $FE
+	LD	L,$FE			; COUNTER/TIMER I/O PAGE
+	LD	C,Z280_IOPR		; REG C POINTS TO I/O PAGE REGISTER
+	.DB	$ED,$6E			; LDCTL	(C),HL
+;
+	; CLEAR END OF COUNT CONDITION TO RESET INTERRUPT
+	IN	A,(Z280_CT0_CMDST)	; GET STATUS
+	RES	1,A			; CLEAR CC
+	OUT	(Z280_CT0_CMDST),A	; SET C/T 0
+;
+	; RESTORE I/O PAGE TO $00
+	LD	L,$00			; NORMAL I/O REG IS $00
+	LD	C,Z280_IOPR		; REG C POINTS TO I/O PAGE REGISTER
+	.DB	$ED,$6E			; LDCTL	(C),HL
+;
+	; RESTORE REGISTERS
+	POP	HL
+	POP	DE
+	POP	BC
+	POP	AF
+;
+	.DB	$ED,$55			; RETIL
+;
+#ENDIF
+;
+;
+;
+HB_TIMINT:
+#IF 0	; *DEBUG*
+	LD	HL,HB_TIMDBGCNT
+	INC	(HL)
+	LD	A,(HL)
+	OUT	(DIAGPORT),A
+	JR	HB_TIMDBG1
+HB_TIMDBGCNT	.DB	0
+HB_TIMDBG1:
+#ENDIF	; *DEBUG*
+;
 ; TIMER HANDLER VECTORS
 ; THESE CAN BE HOOKED AS DESIRED BY DRIVERS
 ;
-HB_TIMINT:
 VEC_TICK:
 	JP	HB_TICK			; TICK PROCESSING VECTOR
 VEC_SECOND:
@@ -3504,7 +3594,6 @@ HB_SECOND:
 	; INCREMENT SECONDS COUNTER
 	LD	HL,HB_SECS		; POINT TO SECONDS COUNTER
 	JP	INC32HL			; INCREMENT AND RETURN
-
 ;
 ; BAD INTERRUPT HANDLER
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index 1f737d7e..905accbf 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.34"
+#DEFINE BIOSVER	"3.1.1-pre.35"
diff --git a/Source/ver.lib b/Source/ver.lib
index 85edf7f6..90f1a10f 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.34"
+	db	"3.1.1-pre.35"
 	endm