Hi Philip,

Sorry, I didn't realise you were using Metalink. You might try the following:

DSEG AT 30h ; Select the DATA segment, starting at location 30h
Your_Var: DS 8 ; Reserve 8 bytes for your variable
Stack: DS 1 ; Dummy variable to mark the beginning of the stack space

CSEG AT 0 ; Select the CODE segment at the beginning of the code space
LJMP Program_Start ; Jump over the interrupt table

ORG 40h ; Let the next bit of code start at address 40h
Program_Start:
MOV SP,#STACK ; Set the stackpointer
; Do some more initialisation, as required

MOV R0,#Your_Var ; Let R0 point to the first byte of Your_Var
MOV @R0,#data1 ; Fill the byte with the desired data
INC R0 ; Point to the next byte
MOV @R0,#data2 ; Fill with data
INC R0 ; On to the next byte, etc. until all bytes are written

; The main of your program goes here

Function:
MOV R0,#Your_Var ; Let R0 point to the first byte of Your_Var
MOV R7,#4 ; Set up R7 as counter
Label1:
MOV A,@R0 ; Get the byte
JNZ Label2 ; Continue if the byte <> 0
RET ; Else, leave the function
Label2:
ACALL Other_Function
INC R0
MOV A,@R0 ; Get the next byte
CLR C ; Clear the Carry flag
RLC ACC ; The 8051 doesn't have a shift, so we rotate through the ; Carry instead. This has the same effect, provided you ; clear the Carry first.
MOV @R0,A ; Save the new value
ACALL Yet_Another_Function
INC R0
DJNZ R7,Label1 ; Repeat this for all 8 bytes
AJMP Function ; If all bytes have been processed, start all over again

END

I hope this will make things a bit easier for you to understand (if it doesn't, I'm afraid you are beyond hope... :-D Just kidding! ).

Regards,
Rob.