Add configurable baud rate through mode.com

Source/HBIOS/sio.asm

@@ -757,6 +757,32 @@ SIO_OST:
 ;
 ;
 SIO_INITDEV:
+;
+	; TEST FOR -1 WHICH MEANS USE CURRENT CONFIG (JUST REINIT)			; PS
+	LD	A,D			; TEST DE FOR										; PS
+	AND	E			; ... VALUE OF -1									; PS
+	INC	A			; ... SO Z SET IF -1								; PS
+	JR	NZ,SIO_INITDEV1	; IF DE == -1, REINIT CURRENT CONFIG		; PS
+;
+	; LOAD EXISTING CONFIG TO REINIT									;PS
+	LD	E,(IY + 4)		; LOW BYTE										;PS
+	LD	D,(IY + 5)		; HIGH BYTE ;PS
+
+; CHANGE INIT TABLE
+;
+SIO_INITDEV1:
+	; DETERMINE DIVISOR
+	PUSH	DE			; SAVE CONFIG
+	CALL	SIO_COMPDIV		; COMPUTE DIVISOR TO BC
+	POP	DE			; RESTORE CONFIG
+	RET	NZ			; ABORT IF COMPDIV FAILS!
+;
+	; GOT A DIVISOR, COMMIT NEW CONFIG
+	LD	(IY + 4),E		; SAVE LOW WORD
+	LD	(IY + 5),D		; SAVE HI WORD
+	
+; *** PUT CODE IN HERE TO UPDATE SIO PROGRAMMING TABLE  BEFORE IT IS PROGRAMMED.	
+
 	HB_DI				; AVOID CONFLICTS
 ;
 	; PROGRAM THE SIO/2 CHIP CHANNEL
@@ -834,6 +860,59 @@ SIO_DETECT:
 ;
 ;
 ;
+SIO_COMPDIV:
+	; WE WANT TO DETERMINE A DIVISOR FOR THE UART CLOCK						; PS FROM UART.ASM
+	; THAT RESULTS IN THE DESIRED BAUD RATE.
+;
+	LD	A,D			; GET CONFIG MSB
+	AND	$1F			; ISOLATE ENCODED BAUD RATE
+
+#IF (SIODEBUG)
+	PUSH AF
+	PRTS(" ENCODE[$")
+	CALL	PRTHEXBYTE
+	PRTC(']')
+	POP AF
+#ENDIF
+	
+	CP SIOBAUD1
+	LD E,$04		; /1 N,8,1
+	JR Z,BREX
+	CP SIOBAUD2
+	LD E,$44		; /16 N,8,1
+	JR Z,BREX
+	CP SIOBAUD3
+	LD E,$84		; /32 N,8,1
+	JR Z,BREX
+	CP SIOBAUD4
+	LD E,$C4		; /64 N,8,1
+	JR Z,BREX		; RET NZ
+
+#IF (SIODEBUG)
+	PUSH AF
+	PRTS(" BR FAIL[$"	
+	CALL PRTHEXBYTE
+	PRTC(']'
+	POP AF
+#ENDIF
+	
+	RET			; NZ stus here indicating fail.
+	
+BREX:			; Z status here indicating success 
+	LD	A,E
+	LD	DE,SIO_INITVALS+3
+	LD (DE),A
+	
+#IF (SIODEBUG)
+	PUSH AF
+	PRTS(" MODE[$")
+	CALL	PRTHEXBYTE
+	PRTC(']')
+	POP AF
+	
+#ENDIF	
+	
+	RET
 SIO_PRTCFG:
 	; ANNOUNCE PORT
 	CALL	NEWLINE			; FORMATTING