Add bank unset. Fix xmodem transfer bios call

Source/HBIOS/dbgmon.asm

@@ -38,7 +38,7 @@ ENA_XM	.EQU	FALSE			; NO ROOM FOR BOTH DSKY+XMODEM
 ENA_XM	.EQU	TRUE			; INCLUDE XMODEM IF SPACE AVAILABLE
 #ENDIF
 ;
-ENA_MBC6502	.EQU	FALSE		; ENABLE OR DISABLE MBC6502 OPTION
+ENA_MBC6502	.EQU	TRUE		; ENABLE OR DISABLE MBC6502 OPTION
 ;
 #INCLUDE "util.asm"
 ;
@@ -71,6 +71,7 @@ UART_ENTRY:
 ; R XXXX		- RUN A PROGRAM AT ADDRESS XXXX
 ; S XX			- SET ACTIVE BANK TO XX
 ; T XXXX 		- X-MODEM TRANSFER TO MEMORY LOCATION XXXX
+; U 			- SET BANK TO PREVIOUS BANK
 ; 6 XX                  - TRANSFER CONTROL TO MBC6502 UNIT XX
 ; X			- EXIT MONITOR
 ;
@@ -129,6 +130,8 @@ SERIALCMDLOOP:
 #IF (BIOS == BIOS_WBW)
 	CP	'S'			; IS IT A "S" (Y/N)
 	JP	Z,SETBNK		; SET BANK COMMAND
+	CP	'U'			; IS IT A "U" (Y/N)
+	JP	Z,UNSETBNK		; UNSET (REVERT) BANK COMMAND		
 #ENDIF
 #IF ((PLATFORM = PLT_MBC) & ENA_MBC6502)
 	CP	'6'			; IS IT A "6" (Y/N)
@@ -225,6 +228,8 @@ SETBNK:
 	LD	HL,TXT_IMERR
 	CALL	PRTSTR
 #ELSE
+	LD	A,($FFE0)		; GET AND SAVE
+	LD	(BNKSAV),A		; CURRENT BANK
 	CALL	BYTEPARM		; GET BANK NUMBER
 	JP	C,ERR			; HANDLE DATA ENTRY ERROR
 	LD	C,A			; PUT IN C FOR FOR FUNC CALL
@@ -233,6 +238,25 @@ SETBNK:
 #ENDIF
 	JP	SERIALCMDLOOP		; NEXT COMMAND
 ;
+;__UNSETBNK___________________________________________________________________
+;
+;	PERFORM UNSET BANK ACTION - REVERT TO BANK BEFORE PREVIOUS SET
+;_____________________________________________________________________________
+;
+UNSETBNK:
+#IF (INTMODE == 1)
+	LD	HL,TXT_IMERR
+	CALL	PRTSTR
+#ELSE
+	LD	A,(BNKSAV)
+	LD	C,A			; PUT IN C FOR FOR FUNC CALL
+	LD	B,BF_SYSSETBNK		; SET BANK FUNCTION
+	CALL	$FFF0			; C HAS BANK, DO IT
+#ENDIF
+	JP	SERIALCMDLOOP		; NEXT COMMAND
+;
+BNKSAV	.DB	00H			; OLD BANK FROM BEFORE SET
+;
 #ENDIF
 ;
 ;__RUN________________________________________________________________________
@@ -365,7 +389,8 @@ XMLOAD:	CALL	WORDPARM		; GET STARTING LOCATION
 	CALL	NEWLINE
 ;
 	LD	BC,$F8F0		; GET CPU SPEED
-	RST	08			; AND MULTIPLY
+	CALL	$FFF0			; CALL HBIOS
+;	RST	08			; AND MULTIPLY
 	LD	A,L			; BY 4
 	PUSH	AF
 	ADD	A,A			; TO CREATE
@@ -1234,7 +1259,10 @@ TXT_HELP	.TEXT	"\r\nMonitor Commands (all values in hex):"
 		.TEXT	"\r\nP xxxx           - Program RAM at address xxxx"
 		.TEXT	"\r\nR xxxx [[yy] [zzzz]]  - Run code at address xxxx"
 		.TEXT	"\r\n                        Pass yy and zzzz to register A and BC"
+#IF (BIOS == BIOS_WBW)
 		.TEXT	"\r\nS xx             - Set bank to xx"
+		.TEXT	"\r\nU                - Set bank to previous bank"
+#ENDIF
 #IF (ENA_XM)
 		.TEXT	"\r\nT xxxx           - X-modem transfer to memory location xxxx"
 #ENDIF