;==============================================================================
;file        :decode.asm
;author      :Andre Long
;due         :March 20, 2006
;description :This program will decode 7 bit data values, using the"parity" 
;             subprocedure to count the number of bits set to 1
;==============================================================================
								;Procedures To
					INCLUDE		Pcmac.inc	;macros
					EXTRN		NEWLINE:FAR		;display a new line
					EXTRN		PUTBIN:FAR		;display binary number
					EXTRN		GETDEC$:FAR		;gets 16-bit decimal number
					EXTRN		PUTDEC$:FAR		;display 16-bit decimal number
					EXTRN		PUTOCT:FAR		;display 16-bit octal number
					EXTRN		PUTSTRNG:FAR	;display a string
					EXTRN		parity:FAR		;count number of ones
;==============================================================================
.MODEL SMALL
.586
.STACK 100h
;==============================================================================
.DATA
PUBLIC		inputNumber
PUBLIC		inputParity
PUBLIC		parityBits
getInput	DB	"Enter the encoded value: ",'$'
outPut1		DB	"Number of bits set to 1 = ", '$'
outPut2		DB	"Binary format of entered number is: ", '$'
receptionA	DB	"Recieved data is good!", '$'
receptionB	DB	"Bad data bit is: ", '$'
formatD		DB	"formatted data = ", '$'
messDecodeD	DB	"decoded data decimal = ", '$'
messdecodeQ	DB	"  decoded data octal = ", '$'
messOct		DB	"decoded data Octal format = ", '$'
inputNumber	DW	?
inputParity	DW	?
parityBits	DW	0
dataFormat	DW	0
holdP1		DW	0000000101010101B
holdP2		DW	0000000100110011B
holdP4		DW	0000000001110000B
holdP8		DW	0000000000001111B
p1			DW	0
p2			DW	0
p4			DW	0
p8			DW	0
storeP1		DW	?
storeP2		DW	?
storeP4		DW	?
storeP8		DW	?
storePbits	DW	0
mmask		DW	0000100000000000B
messRepairD	DB	"Repaired Data Decimal: ", '$'
messRepairB	DB	"Repaired Data Binary: ", '$'
messRepairQ	DB	"Repaired Data Octal: ", '$'
cargo		DW	?
dp1			DW	0
dp2			DW	0
dp3			DW	0
;==============================================================================
.CODE
decode		proc
			_Begin
			sPutStr		getInput
			call		GETDEC$
			mov			dataFormat,	ax
			and			ax,	holdP1
			mov			inputParity,	ax
			call		parity
			mov			bx,	parityBits
			mov			p1,	bx
			mov			ax,	p1
			
ntest1:		mov			bx,	2
			mov			dx,	0
			div			bx						;Ax = Dx:Ax / bx
			cmp			dx,	0					;dx stores the remainder 
			je			nEven1
			jmp			nOdd1
			
			
nEven1:		mov			storeP1,	0000000000000000B
			jmp			Par2
			
nOdd1:		mov			storeP1,	0000000000000001B
			jmp			Par2
			
			
Par2:		mov			ax,	dataFormat
			and			ax,	holdP2
			mov			inputParity,	ax
			call		parity
			mov			bx, parityBits
			mov			p2,	bx
			mov			ax,	p2
			
ntest2:		mov			bx,	2
			mov			dx,	0
			div			bx						;Ax = Dx:Ax / bx
			cmp			dx,	0					;dx stores the remainder 
			je			nEven2
			jmp			nOdd2
			
nEven2:		mov			storeP2,	0000000000000000B
			jmp			Par4
			
nOdd2:		mov			storeP2,	0000000000000001B
			jmp			Par4
			
Par4:		mov			ax,	dataFormat
			and			ax,	holdP4
			mov			inputParity,	ax
			call		parity
			mov			bx,	parityBits
			mov			p4,	bx
			mov			ax,	p4
			
ntest4:		mov			bx,	2
			mov			dx,	0
			div			bx						;Ax = Dx:Ax / bx
			cmp			dx,	0					;dx stores the remainder 
			je			nEven4
			jmp			nOdd4
			
nEven4:		mov			storeP4,	0000000000000000B
			jmp			Par8
			
nOdd4:		mov			storeP4,	0000000000000001B
			jmp			Par8
			
Par8:		mov			ax,	dataFormat
			and			ax,	holdP8
			mov			inputParity,	ax
			call		parity
			mov			bx,	parityBits
			mov			p8,	bx
			mov			ax,	p8
			
ntest8:		mov			bx,	2
			mov			dx,	0
			div			bx						;Ax = Dx:Ax / bx
			cmp			dx,	0					;dx stores the remainder 
			je			nEven8
			jmp			nOdd8
			
nEven8:		mov			storeP8,	0000000000000000B
			jmp			red
			
nOdd8:		mov			storeP8,	0000000000000001B
			jmp			red
			
			
red:		mov			bx,	0
			or			bx,	storeP8
			shl			bx,	1
			or			bx,	storeP4
			shl			bx,	1
			or			bx,	storeP2
			shl			bx,	1
			or			bx,	storeP1	
			cmp			bx,	0
			
			jnz			ptB
			jmp			ptA
			
ptA:		sPutStr		receptionA
			jmp			ptC


ptB:		sPutStr		receptionB
			mov			ax,bx
			mov			cx,	bx
			call		putdec$
			mov			dx,	mmask			;start of the repair process
			shr			dx,	cl
			mov			ax,	dataFormat
			xor			ax,	dx
			mov			dataFormat,	ax
			call		newline
			sPutStr		messRepairD
			call		putdec$
			call		newline
			sPutStr		messRepairB
			call		putbin
			call		newline
			sPutStr		messRepairQ
			mov			bl, 1
			call		putoct
			jmp			ptC


ptC:		mov			ax,	dataFormat
			and			ax,	0000000000000111B
			mov			dp1,	ax
			
			mov			ax,	dataFormat
			and			ax,	0000000001110000B
			shr			ax,	1
			mov			dp2,	ax
			
			mov			ax,	dataFormat
			and			ax,	0000000100000000B
			shr			ax,	2
			add			ax,	dp1
			add			ax,	dp2
			call		newline
			sPutStr		messDecodeD
			call		putdec$
			sPutStr		messDecodeQ
			mov			bl,	1
			call		putoct
			
						

			
			
			_Exit
decode		endp
			end			decode