here is my code

EXTRN CODE (CRC16_INIT)
EXTRN CODE (CRC16_ADD)
EXTRN CODE (CRC16_GET)

BITS40 equ 30h
RESULT equ 40h

CSEG AT 0H

mov sp,#060h
mov a,#041h
CALL CRC16_INIT
CALL CRC16_ADD
CALL CRC16_GET


END


VAR SEGMENT DATA
extrn CODE (UTIL_ADCAD)

CSEG AT 0ef0H
public CRC16_INIT
public CRC16_ADD
public CRC16_GET

CRC16_INIT:
mov D_CRC16_HI,#0 ; Clear CRC16 High
mov D_CRC16_LO,#0 ; Clear CRC16 Low
ret ; Return To Caller

CRC16_ADD:
jmp CRC16_ADD_TABLE ; Use Calculation Method

CRC16_GET:
mov dph,D_CRC16_HI ; Get CRC16 High
mov dpl,D_CRC16_LO ; Get CRC16 Low
ret ; Return To Caller
CRC16_ADD_TABLE:
push dph ; Save DPH
push dpl ; Save DPL
push acc ; Save Acc
;
mov dptr,#CRC16_DATA ; Point To Table
xrl a,D_CRC16_HI ; XOR High Of CRC With Character
call UTIL_ADCAD ; Add 'A' To 'DPTR'
call UTIL_ADCAD ; Add 'A' To 'DPTR' (Yes, Twice)
;
clr a ; Clear For MOVC
movc a,@a+dptr ; Get High Of Table Entry
xrl a,D_CRC16_LO ; XOR With Low
mov D_CRC16_HI,a ; Store To High
;
mov a,#1 ; Get Low Byte
movc a,@a+dptr ; Get Low Of Table Entry
mov D_CRC16_LO,a ; Store To Low Of CRC
;
pop acc ; Recover Acc
pop dpl ; Recover DPL
pop dph ; Recover DPH
ret ; Return To Caller
;
;****************************************************************************
;
; Data For Table Method
;
CRC16_DATA: dw 00000h, 01021h, 02042h, 03063h, 04084h, 050A5h, 060C6h, 070E7h
dw 08108h, 09129h, 0A14Ah, 0B16Bh, 0C18Ch, 0D1ADh, 0E1CEh, 0F1EFh
dw 01231h, 00210h, 03273h, 02252h, 052B5h, 04294h, 072F7h, 062D6h
dw 09339h, 08318h, 0B37Bh, 0A35Ah, 0D3BDh, 0C39Ch, 0F3FFh, 0E3DEh
dw 02462h, 03443h, 00420h, 01401h, 064E6h, 074C7h, 044A4h, 05485h
dw 0A56Ah, 0B54Bh, 08528h, 09509h, 0E5EEh, 0F5CFh, 0C5ACh, 0D58Dh
dw 03653h, 02672h, 01611h, 00630h, 076D7h, 066F6h, 05695h, 046B4h
dw 0B75Bh, 0A77Ah, 09719h, 08738h, 0F7DFh, 0E7FEh, 0D79Dh, 0C7BCh
dw 048C4h, 058E5h, 06886h, 078A7h, 00840h, 01861h, 02802h, 03823h
dw 0C9CCh, 0D9EDh, 0E98Eh, 0F9AFh, 08948h, 09969h, 0A90Ah, 0B92Bh
dw 05AF5h, 04AD4h, 07AB7h, 06A96h, 01A71h, 00A50h, 03A33h, 02A12h
dw 0DBFDh, 0CBDCh, 0FBBFh, 0EB9Eh, 09B79h, 08B58h, 0BB3Bh, 0AB1Ah
dw 06CA6h, 07C87h, 04CE4h, 05CC5h, 02C22h, 03C03h, 00C60h, 01C41h
dw 0EDAEh, 0FD8Fh, 0CDECh, 0DDCDh, 0AD2Ah, 0BD0Bh, 08D68h, 09D49h
dw 07E97h, 06EB6h, 05ED5h, 04EF4h, 03E13h, 02E32h, 01E51h, 00E70h
dw 0FF9Fh, 0EFBEh, 0DFDDh, 0CFFCh, 0BF1Bh, 0AF3Ah, 09F59h, 08F78h
dw 09188h, 081A9h, 0B1CAh, 0A1EBh, 0D10Ch, 0C12Dh, 0F14Eh, 0E16Fh
dw 01080h, 000A1h, 030C2h, 020E3h, 05004h, 04025h, 07046h, 06067h
dw 083B9h, 09398h, 0A3FBh, 0B3DAh, 0C33Dh, 0D31Ch, 0E37Fh, 0F35Eh
dw 002B1h, 01290h, 022F3h, 032D2h, 04235h, 05214h, 06277h, 07256h
dw 0B5EAh, 0A5CBh, 095A8h, 08589h, 0F56Eh, 0E54Fh, 0D52Ch, 0C50Dh
dw 034E2h, 024C3h, 014A0h, 00481h, 07466h, 06447h, 05424h, 04405h
dw 0A7DBh, 0B7FAh, 08799h, 097B8h, 0E75Fh, 0F77Eh, 0C71Dh, 0D73Ch
dw 026D3h, 036F2h, 00691h, 016B0h, 06657h, 07676h, 04615h, 05634h
dw 0D94Ch, 0C96Dh, 0F90Eh, 0E92Fh, 099C8h, 089E9h, 0B98Ah, 0A9ABh
dw 05844h, 04865h, 07806h, 06827h, 018C0h, 008E1h, 03882h, 028A3h
dw 0CB7Dh, 0DB5Ch, 0EB3Fh, 0FB1Eh, 08BF9h, 09BD8h, 0ABBBh, 0BB9Ah
dw 04A75h, 05A54h, 06A37h, 07A16h, 00AF1h, 01AD0h, 02AB3h, 03A92h
dw 0FD2Eh, 0ED0Fh, 0DD6Ch, 0CD4Dh, 0BDAAh, 0AD8Bh, 09DE8h, 08DC9h
dw 07C26h, 06C07h, 05C64h, 04C45h, 03CA2h, 02C83h, 01CE0h, 00CC1h
dw 0EF1Fh, 0FF3Eh, 0CF5Dh, 0DF7Ch, 0AF9Bh, 0BFBAh, 08FD9h, 09FF8h
dw 06E17h, 07E36h, 04E55h, 05E74h, 02E93h, 03EB2h, 00ED1h, 01EF0h
;

RSEG VAR
D_CRC16_HI: ds 1
D_CRC16_LO: ds 1

end