Added Mode command

Source/Apps/Build.cmd

@@ -16,6 +16,7 @@ call :asm Assign || goto :eof
 call :asm Format || goto :eof
 call :asm Talk || goto :eof
 call :asm OSLdr || goto :eof
+call :asm Mode || goto :eof
 
 zx Z80ASM -SYSGEN/F
 
@@ -26,6 +27,5 @@ goto :eof
 :asm
 echo.
 echo Building %1...
-rem tasm -t80 -b -g3 -fFF %1.asm %1.com %1.lst
 tasm -t80 -g3 -fFF %1.asm %1.com %1.lst
 goto :eof

Source/Apps/Decode.asm

@@ -0,0 +1,79 @@
+;
+;==================================================================================================
+; DECODE 32-BIT VALUES FROM A 5-BIT SHIFT-ENCODED VALUE
+;==================================================================================================
+;
+;   Copyright (C) 2014 John R. Coffman.  All rights reserved.
+;   Provided for hobbyist use on the Z180 SBC Mark IV board.
+;
+; This program is free software: you can redistribute it and/or modify
+; it under the terms of the GNU General Public License as published by
+; the Free Software Foundation, either version 3 of the License, or
+; (at your option) any later version.
+;
+; This program is distributed in the hope that it will be useful,
+; but WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+; GNU General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+; THE FUNCTION(S) IN THIS FILE ARE BASED ON LIKE FUNCTIONS CREATED BY JOHN COFFMAN
+; IN HIS UNA BIOS PROJECT.  THEY ARE INCLUDED HERE BASED ON GPLV3 PERMISSIBLE USE.
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+; An encoded value (V) is defined as V = C * 2^X * 3^Y
+; where C is a prearranged constant, X is 0 or 1 and Y is 0-15
+; The encoded value is stored as 5 bits: YXXXX
+; At present, C=75 for baud rate encoding and C=3 for CPU OSC encoding
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;  DECODE
+;
+; Enter with:
+;	HL	=  word to be decoded (5-bits)    FXXXX
+;		   F=extra 3 factor, XXXX=shift factor, reg H must be zero
+;	DE	=  encode divisor OSC_DIV = 3, or BAUD_DIV = 75
+;
+; Exit with:
+;	DE:HL	=  decoded value
+;       A	=  non-zero on error
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+decode:
+	ld	a,h			; set to test
+	ld	c,$ff			; presume error condition
+	or	a			; test for zero
+	jr	nz,decode9		; not an encoded value
+	ld	a,l			; get low order 5 bits
+	cp	32			; test for error
+	jr	nc,decode9		; error return if not below
+	; argument hl is validated
+	ld	h,d
+	ld	l,e			; copy to hl
+	cp	16	
+	jr	c,decode2		; if < 16, no 3 factor
+	add	hl,de			; introduce factor of 3
+	add	hl,de			; **
+decode2:	
+	ld	de,0			; zero the high order
+	and	15			; mask to 4 bits
+	jr	z,decode8		; good exit
+	ld	c,b			; save b-reg
+	ld	b,a			;
+decode3:	
+	add	hl,hl			; shift left by 1, set carry
+	rl	e	
+	rl	d			; **
+	djnz	decode3	
+	ld	b,c			; restore b-reg
+decode8:	
+	ld	c,0			; signal good return
+decode9:	
+	ld	a,c			; error code test
+	or	a			; error code in reg-c and z-flag
+	ret

Source/Apps/Encode.asm

@@ -0,0 +1,75 @@
+;
+;==================================================================================================
+; ENCODE 32-BIT VALUES TO A 5-BIT SHIFT-ENCODED VALUE
+;==================================================================================================
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+; An encoded value (V) is defined as V = C * 2^X * 3^Y
+; where C is a prearranged constant, Y is 0 or 1 and X is 0-15
+; The encoded value is stored as 5 bits: YXXXX
+; At present, C=75 for baud rate encoding and C=3 for CPU OSC encoding
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;  ENCODE
+;
+; Enter with:
+;	DE:HL	=  dword value to be encoded
+;	C	=  divisor (0 < C < 256)
+;		   encode divisor OSC_DIV = 3, or BAUD_DIV = 75
+;
+; Exit with:
+;	C	=  encoded value
+;       A	=  non-zero on error
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+encode:
+	; incoming value of zero is a failure
+	call	encode5			; test DE:HL for zero
+	jr	z,encode4		; if zero, failure return
+;
+	; apply encoding divisor
+	call	div32x8			; DE:HL / C (remainder in A)
+	or	a			; set flags to test for zero
+	ret	nz			; error if not evenly divisible
+;
+	; test divide by 3 to see if it is possible
+	push	de			; save working
+	push	hl			; ... value
+	ld	c,3			; divide by 3
+	call	div32x8			; ... test
+	pop	hl			; restore working
+	pop	de			; ... value
+;
+	; implmement divide by 3 if possible
+	ld	c,$00			; init result in c w/ div 3 flag clear
+	or	a			; set flags to test for remainder
+	jr	nz,encode2		; jump if it failed
+;
+	; if divide by 3 worked, do it again for real
+	ld	c,3			; setup to divide by 3 again
+	call	div32x8			; do it
+	ld	c,$10			; init result in c w/ div 3 flag set
+;
+encode2:
+	; loop to determine power of 2
+	ld	b,16			; can only represent up to 2^15
+encode3:
+	srl	d			; right shift de:hl into carry
+	rr	e			; ...
+	rr	h			; ...
+	rr	l			; ...
+	jr	c,encode5		; if carry, then done, c has result
+	inc	c			; bump the result value
+	djnz	encode3			; keep shifting if possible
+encode4:
+	or	$ff			; signal error
+	ret				; and done
+;
+encode5:
+	; test de:hl for zero (sets zf, clobbers a)
+	ld	a,h
+	or	l
+	or	d
+	or	e
+	ret				; ret w/ Z set if DE:HL == 0

Source/Apps/bcd.asm

@@ -0,0 +1,104 @@
+;;
+;; make a bcd number from a binary number
+;; 32 bit binary number in hl:bc, result stored at (de)
+;; de is preserved, all other regs destroyed
+;;
+;bin2bcd:
+;	push	ix		; save ix
+;	push	bc		; move bc
+;	pop	ix		; ... to ix
+;	ld	c,32		; loop for 32 bits of binary dword
+;;
+;bin2bcd0:
+;	; outer loop (once for each bit in binary number)	
+;	ld	b,5		; loop for 5 bytes of result
+;	push	de		; save de
+;	add	ix,ix		; left shift next bit from hl:ix
+;	adc	hl,hl		; ... into carry
+;;
+;bin2bcd1:
+;	; inner loop (once for each byte of bcd number)
+;	ld	a,(de)		; get it
+;	adc	a,a		; double it w/ carry
+;	daa			; decimal adjust
+;	ld	(de),a		; save it
+;	inc	de		; point to next bcd byte
+;	djnz	bin2bcd1	; loop thru all bcd bytes
+;;
+;	; remainder of outer loop
+;	pop	de		; recover de
+;	dec	c		; dec bit counter
+;	jr	nz,bin2bcd0	; loop till done with all bits
+;	pop	ix		; restore ix
+;
+; make a bcd number from a binary number
+; 32 bit binary number in de:hl, result stored at (bc)
+; on output hl = bcd buf adr
+;
+bin2bcd:
+	push	ix		; save ix
+	; convert from de:hl -> (bc) to hl:ix -> (de)
+	; hl -> ix, de -> hl, bc -> de
+	ex	de,hl
+	push	de
+	pop	ix
+	push	bc
+	pop	de
+;
+	ld	c,32		; loop for 32 bits of binary dword
+;
+bin2bcd0:
+	; outer loop (once for each bit in binary number)	
+	ld	b,5		; loop for 5 bytes of result
+	push	de		; save de
+	add	ix,ix		; left shift next bit from hl:ix
+	adc	hl,hl		; ... into carry
+;
+bin2bcd1:
+	; inner loop (once for each byte of bcd number)
+	ld	a,(de)		; get it
+	adc	a,a		; double it w/ carry
+	daa			; decimal adjust
+	ld	(de),a		; save it
+	inc	de		; point to next bcd byte
+	djnz	bin2bcd1	; loop thru all bcd bytes
+;
+	; remainder of outer loop
+	pop	de		; recover de
+	dec	c		; dec bit counter
+	jr	nz,bin2bcd0	; loop till done with all bits
+	ex	de,hl		; hl -> bcd buf
+	pop	ix		; restore ix
+	ret
+;
+; print contents of 5 byte bcd number at (hl)
+; with leading zero suppression
+; all regs destroyed
+;
+prtbcd:
+	inc	hl		; bump hl to point to
+	inc	hl		; ...
+	inc	hl		; ...
+	inc	hl		; ... last byte of bcd
+	ld	b,5		; loop for 5 bytes
+	ld	c,0		; start by suppressing leading zeroes
+;
+prtbcd1:
+	; loop to print one bcd byte (two digits)
+	xor	a		; clear accum
+	rld			; rotate first nibble into a
+	call	prtbcd2		; print it
+	xor	a		; clear accum
+	rld			; rotate second nibble into a
+	call	prtbcd2		; print it
+	dec	hl		; point to prior byte
+	djnz	prtbcd1		; loop till done
+	ret			; return
+;
+prtbcd2:
+	; subroutine to print a digit in a
+	cp	c		; compare incoming to c
+	ret	z		; if equal, suppressing, abort
+	dec	c		; make c negative to stop suppression
+	add	a,'0'		; offset to printable value
+	jp	prtchr		; exit via character out

Source/HBIOS/hbios.asm

@@ -2665,9 +2665,9 @@ PS_PRTSC0:
 	PUSH	DE			; PRESERVE DE
 	CALL	PC_COMMA		; FORMATTING
 	LD	A,E			; GET CONFIG BYTE
-	RLCA				; SHIFT RELEVANT BITS
-	RLCA				; ...
-	RLCA				; ...
+	RRCA				; SHIFT RELEVANT BITS
+	RRCA				; ...
+	RRCA				; ...
 	AND	$07			; AND ISOLATE DATA BITS VALUE
 	LD	HL,PS_STPARMAP		; CHARACTER LOOKUP TABLE
 	CALL	ADDHLA			; APPLY OFFSET
@@ -2678,8 +2678,8 @@ PS_PRTSC0:
 	; PRINT STOP BITS
 	CALL	PC_COMMA		; FORMATTING
 	LD	A,E			; GET CONFIG BYTE
-	RLCA				; SHIFT RELEVANT BITS
-	RLCA				; ...
+	RRCA				; SHIFT RELEVANT BITS
+	RRCA				; ...
 	AND	$01			; AND ISOLATE DATA BITS VALUE
 	ADD	A,'1'			; MAKE IT A CHARACTER
 	CALL	COUT			; AND PRINT