Listing 1—I used this coding technique to meet the strict timing requirements of the project. 
The routine sends a configurable number of pulses to the LCD clock input with less than three
 PIC instructions per pulse on average! Try to do it with a classic loop.

;Send W pulses to the XSCK line (W = 0 to 60). Execution duration:100
;ns × (2xW + 20) for W < 60. Average with W = 20 (worst case) giving 
;three instructions/pulse (300 ns).
**************************************************************************
send_upto60_pulses	;Limited to 60 because of page boundary
input in tmp_send_w_pulses
	movf	tmp_send_w_pulses,W
	sublw	.60	;Calculate 2 × (60 – w)
	rlncf	WREG
	rlncf	WREG
	movwf	tmp_send_w_pulses
	goto	pulsesaligned
pulsesnotaligned
	org	(1 + high pulsesnotaligned)*.256 
	;Must start on a page boundary
pulsesaligned
	movlw	high pulsesaligned
	movwf	PCLATH	;High byte of new PC should be defined		
movf	tmp_send_w_pulses,W
	addwf	PCL,F	;Jump to next instruction if W = 0 (60 pulses)
	bsf	PORTB,RB_LCDXSCL_BIT	;pulse 60
	bcf	PORTB,RB_LCDXSCL_BIT
	bsf	PORTB,RB_LCDXSCL_BIT	;pulse 59
	bcf	PORTB,RB_LCDXSCL_BIT
	bsf	PORTB,RB_LCDXSCL_BIT	;pulse 58
	bcf	PORTB,RB_LCDXSCL_BIT
					;etc…				
	bsf	PORTB,RB_LCDXSCL_BIT	;pulse 02
	bcf	PORTB,RB_LCDXSCL_BIT
	bsf	PORTB,RB_LCDXSCL_BIT	;pulse 01
	bcf	PORTB,RB_LCDXSCL_BIT
	retlw	0	;Must be in the same page as the first one