;***********************************************************************************
;MAKE_CRC16 - This routine generates a CRC-16 shift register from the data byte stored
;in the DATA_REG register.  DATA_TEMP0 and DATA_TEMP1 are used to buffer the data
;and prevent it from being corrupted by the CRC-16 generation process.  
;***********************************************************************************
MAKE_CRC16
	movf	DATA_REG,W
	movwf	DATA_TEMP0			;Store data in temporary register
	movlw	'00001000'b			;Set counter for 8 data bits	
	movwf	NUMBER_BITS			;Load counter register
More_Rotates
	movf	DATA_TEMP0,W		;Move buffered data to 2nd buffer
	movwf	DATA_TEMP1			;This register is corrupted with every pass
	movf	CRC16_HI,W			;Move upper shift register to working reg.
	xorwf	DATA_TEMP1			;XOR shift register with data register
	btfss	DATA_TEMP1,7		;MSB is XOR of stage16 and input data bit
	goto	No_Xorwf			;If bit is clear then no complement of stage2,15
	movlw 	'00000010'b			;Prepare to complement stage2
	xorwf	CRC16_LO			;Complement stage2 of shift register	
	movlw 	'01000000'b			;Prepare to complement stage15
	xorwf	CRC16_HI			;Complement stage15 of shift register	
No_Xorwf
	rlf	DATA_TEMP0			;Rotate next data bit into position
	rlf	DATA_TEMP1			;Rotate XOR of input into CRC16_LO
	rlf	CRC16_LO			;Shift CRC16 register
	rlf	CRC16_HI			;Shift CRC16 register
	decfsz	NUMBER_BITS			;Count out 8 data bits
	goto	More_Rotates			;Not finished with this data byte
	return					;This byte is finished