Ahmet,

Perhaps this may be of some help.

clock_mult:

; 	Init Default no multiplier

	MOV 	PMR,#080H 

; 	Wait for ring modulator to stop

wait_rgmd:
	MOV 	A,EXIF
	JB 	ACC.2,wait_rgmd

; 	Clear the CTM bit

	MOV 	PMR,#080H

; 	*** Must set XTAL multiplier prior to setting CTM ***

	MOV	PMR,#88H

;	*** Set CTM to latch crystal multiplier setting ***
	
	MOV 	PMR,#98H

;	*** Wait for CKRY, (EXIF.3) to set indicating at Freq ***

wait_ckry:
	MOV 	A,EXIF
	JNB 	ACC.3,wait_ckry

;	*** Set CTM, to enable crystal multiplier of @ rate of 4

	MOV	PMR,#10H
	ret