Refactor ROM Loader Baud Rate Change

- The baud rate change functionality in ROM Loader was refactored to reduce it's size and be consistent with the approach used in the MODE command.

Source/HBIOS/romldr.asm

@@ -31,7 +31,7 @@
 ; avoid the problem where the code is overlaid during the loading of
 ; the desired executable image.
 ;
-#INCLUDE "std.asm"	; standard RomWBW constants
+#include "std.asm"	; standard RomWBW constants
 ;
 #ifndef BOOT_DEFAULT
 #define BOOT_DEFAULT "H"
@@ -754,54 +754,15 @@ setcon:
 	call	skipws			; skip whitespace
 	call	isnum			; do we have a number?
 	jp	nz,docon		; if no we don't change baudrate
-	call	getbnum			; return in HL:BC
-;
-	ld	e,32			; search baud rate table
-	push	de			; for a matching entry
-	ld	de,tbl_baud
-nextbaud:
-	ex	de,hl			; hl = tbl_baud, de = msw
-	ld	a,d			; check all four bytes
-	cp	(hl)			; against HL:BC
-	inc	hl			; exit to next table
-	jr	nz,mm1			; entry on mismatch
-	ld	a,e
-	cp	(hl)
-	inc	hl
-	jr	nz,mm2
-	ld	a,b
-	cp	(hl)
-	inc	hl
-	jr	nz,mm3
-	ld	a,c
-	cp	(hl)
-	inc	hl
-	jr	nz,mm4
-;
-	; we have a match
-	pop	de			; get our count value
-	ld	a,32
-	sub	e
-	jr	setspd
-;
-mm1:	inc	hl
-mm2:	inc	hl
-mm3:	inc	hl
-mm4:	ex	(sp),hl			; hl = count value, stack = tbl_baud, de = msw
-	dec	l
-	ex	(sp),hl			; hl = tbl_baud, stack= count
-	ex	de,hl			; hl = msw, de = tbl_baud
-	jr	nz,nextbaud
-;
-	; Failed to match
-	pop	de
-	jp	err_invcmd
-;
-setspd:	ld	(newspeed),a		; save validated baud rate
-;
-	ld	hl,str_chspeed		; notify user
-	call	pstr			; to change
-	call	cin			; speed
+	push	de			; move char ptr
+	pop	ix			; ... to IX
+	call	getnum32		; get 32-bit number
+	jp	c,err_invcmd		; handle overflow
+	ld	c,75			; Constant for baud rate encode
+	call	encode			; encode into C:4-0
+	jp	nz,err_invcmd		; handle encoding error
+	ld	a,c			; move encoded value to A
+	ld	(newspeed),a		; save validated baud rate
 ;
 	; Get the current settings for chosen console
 	ld	b,BF_CIOQUERY		; BIOS serial device query
@@ -815,12 +776,18 @@ setspd:	ld	(newspeed),a		; save validated baud rate
 	ld	hl,newspeed		; and load in new
 	or	(hl)			; baud rate
 	ld	d,a
+;
+	ld	hl,str_chspeed		; notify user
+	call	pstr			; to change speed
+	call	ldelay			; time for line to flush
 ;
 	ld	b,BF_CIOINIT		; BIOS serial init
 	ld	a,(newcon)		; get serial device unit
 	ld	c,a			; ... into C
 	rst	08			; call HBIOS
 	jp	nz,err_invcmd		; handle error
+;
+	call	cin			; wait for char at new speed
 ;
 	; Notify user, we're outta here....
 docon:	ld	hl,str_newcon		; new console msg
@@ -842,90 +809,6 @@ docon:	ld	hl,str_newcon		; new console msg
 	call	pstr			; do it
 	ret
 ;
-;=======================================================================
-; Get numeric chars at DE and convert to BCD number returned in HL:BC
-;=======================================================================
-;
-getbnum:ld	bc,0		; lsw
-	ld	hl,0		; msw
-getbnum1:
-	ld	a,(de)		; get the active char
-	cp	'0'		; compare to ascii '0'
-	jr	c,getbnum2	; abort if below
-	cp	'9' + 1		; compare to ascii '9'
-	jr	nc,getbnum2	; abort if above
-;
-	sub	'0'		; convert '0'-'9' to 0-9
-;
-	push	de		; save char posn
-	push	hl		; save hl bcd
-;
-	ld	hl,tmpbcd	; rotate 1 nyble in A
-	ld	(hl),c		; through HL:BC
-	rld
-	ld	c,(hl)
-	ld	(hl),b
-	rld
-	ld	b,(hl)
-	pop	de		; get hl bcd
-	ld	(hl),e
-	rld
-	ld	e,(hl)
-	ld	(hl),d
-	rld
-	ld	d,(hl)
-	ld	h,d
-	ld	l,e
-;
-	pop	de		; get char posn
-	inc	de		; bump to next char
-	jr	getbnum1	; loop
-;
-getbnum2:
-	or	a		; with flags set, CF is cleared
-	ret
-;
-tmpbcd:	.db	0
-;
-#DEFINE PACK(a,b,c,d,e,f,g) \
-#DEFCONT \ 	.db	(16*('0'-'0'))+(a-'0'))
-#DEFCONT \ 	.db	(16*(b-'0'))+(c-'0'))
-#DEFCONT \ 	.db	(16*(d-'0'))+(e-'0'))
-#DEFCONT \ 	.db	(16*(f-'0'))+(g-'0'))
-;
-tbl_baud:
-	PACK('0','0','0','0','0','7','5') ;      75  0 >  0
-	PACK('0','0','0','0','1','5','0') ;     150  1 >  1
-	PACK('0','0','0','0','3','0','0') ;     300  3 >  2
-	PACK('0','0','0','0','6','0','0') ;     600  5 >  3
-	PACK('0','0','0','1','2','0','0') ;    1200  7 >  4
-	PACK('0','0','0','2','4','0','0') ;    2400  9 >  5
-	PACK('0','0','0','4','8','0','0') ;    4800 11 >  6
-	PACK('0','0','0','9','6','0','0') ;    9600 13 >  7
-	PACK('0','0','1','9','2','0','0') ;   19200 15 >  8
-	PACK('0','0','3','8','4','0','0') ;   38400 17 >  9
-	PACK('0','0','7','6','8','0','0') ;   76800 19 > 10
-	PACK('0','1','5','3','6','0','0') ;  153600 21 > 11
-	PACK('0','3','0','7','2','0','0') ;  307200 23 > 12
-	PACK('0','6','1','4','4','0','0') ;  614400 25 > 13
-	PACK('1','2','2','8','8','0','0') ; 1228800 27 > 14
-	PACK('2','4','5','7','6','0','0') ; 2457600 29 > 15
-	PACK('0','0','0','0','2','2','5') ;     225  2 > 16
-	PACK('0','0','0','0','4','5','0') ;     450  4 > 17
-	PACK('0','0','0','0','9','0','0') ;     900  6 > 18
-	PACK('0','0','0','1','8','0','0') ;    1800  8 > 19
-	PACK('0','0','0','3','6','0','0') ;    3600 10 > 20
-	PACK('0','0','0','7','2','0','0') ;    7200 12 > 21
-	PACK('0','0','1','4','4','0','0') ;   14400 14 > 22
-	PACK('0','0','2','8','8','0','0') ;   28800 16 > 23
-	PACK('0','0','5','7','6','0','0') ;   57600 18 > 24
-	PACK('0','1','1','5','2','0','0') ;  115200 20 > 25
-	PACK('0','2','3','0','4','0','0') ;  230400 22 > 26
-	PACK('0','4','6','0','8','0','0') ;  460800 24 > 27
-	PACK('0','9','2','1','6','0','0') ;  921600 26 > 28
-	PACK('1','8','4','3','2','0','0') ; 1843200 28 > 29
-	PACK('3','6','8','6','4','0','0') ; 3686400 30 > 30
-	PACK('7','3','7','2','8','0','0') ; 7372800 31 > 31
 #endif
 ;
 ; Set RomWBW HBIOS Diagnostic Level
@@ -1514,10 +1397,13 @@ pvol1:
 nl2:
 	call	nl			; double newline
 nl:
+	push	af
 	ld	a,cr			; cr
 	call	cout			; send it
 	ld	a,lf			; lf
-	jp	cout			; send it and return
+	call	cout			; send it and return
+	pop	af
+	ret
 ;
 ; Print a dot on console
 ;
@@ -1929,6 +1815,110 @@ hexconv:
 	daa
 	ret
 ;
+#if (BIOS == BIOS_WBW)
+;
+; Get numeric chars and convert to 32-bit number returned in DE:HL
+; IX points to start of char buffer
+; Carry flag set on overflow
+;
+getnum32:
+	ld	de,0		; Initialize DE:HL
+	ld	hl,0		; ... to zero
+getnum32a:
+	ld	a,(ix)		; get the active char
+	cp	'0'		; compare to ascii '0'
+	jr	c,getnum32c	; abort if below
+	cp	'9' + 1		; compare to ascii '9'
+	jr	nc,getnum32c	; abort if above
+;
+	; valid digit, multiply DE:HL by 10
+	; X * 10 = (((x * 2 * 2) + x)) * 2
+	push	de
+	push	hl
+;	
+	call	getnum32e	; DE:HL *= 2
+	jr	c,getnum32d	; if overflow, ret w/ CF & stack pop
+;	
+	call	getnum32e	; DE:HL *= 2
+	jr	c,getnum32d	; if overflow, ret w/ CF & stack pop
+;
+	pop	bc		; DE:HL += X
+	add	hl,bc
+	ex	de,hl
+	pop	bc
+	adc	hl,bc
+	ex	de,hl
+	ret	c		; if overflow, ret w/ CF
+;	
+	call	getnum32e	; DE:HL *= 2
+	ret	c		; if overflow, ret w/ CF
+;
+	; now add in new digit
+	ld	a,(ix)		; get the active char
+	sub	'0'		; make it binary
+	add	a,l		; add to L, CF updated
+	ld	l,a		; back to L
+	jr	nc,getnum32b	; if no carry, done
+	inc	h		; otherwise, bump H
+	jr	nz,getnum32b	; if no overflow, done
+	inc	e		; otherwise, bump E
+	jr	nz,getnum32b	; if no overflow, done
+	inc	d		; otherwise, bump D
+	jr	nz,getnum32b	; if no overflow, done
+	scf			; set carry flag to indicate overflow
+	ret			; and return
+;
+getnum32b:
+	inc	ix		; bump to next char
+	jr	getnum32a	; loop
+;
+getnum32c:
+	; successful completion
+	xor	a		; clear flags
+	ret			; and return
+;
+getnum32d:
+	; special overflow exit with stack fixup
+	pop	hl		; burn 2
+	pop	hl		; ... stack entries
+	ret			; and return
+;
+getnum32e:
+	; DE:HL := DE:HL * 2
+	sla	l
+	rl	h
+	rl	e
+	rl	d
+	ret
+;
+; Integer divide DE:HL by C
+; result in DE:HL, remainder in A
+; clobbers F, B
+;
+div32x8:
+	xor	a
+	ld	b,32
+div32x8a:
+  	add	hl,hl
+	rl	e
+	rl	d
+	rla
+	cp	c
+	jr	c,div32x8b
+	sub	c
+	inc	l
+div32x8b:
+  	djnz	div32x8a
+	ret
+;
+DIV32X8	.equ	div32x8
+;
+#include "encode.asm"	; baud rate encoding routine
+;
+encode	.equ	ENCODE
+;
+#endif
+;
 ;=======================================================================
 ; Console character I/O helper routines (registers preserved)
 ;=======================================================================