Calling a TABLE by using Indirect Addressing

[Suraj143]

Hi I want to call a TABLE by using indirect addressing. Now I’m doing like this.

	movlw 	01h
	movwf	11h	;GP register
	movlw	02h
	movwf	12h	;GP register

So if there is more registers I want to write more.

I can clear the GP registers using indirect addressing like below.

	movlw	11h
	movwf	FSR
	clrf	INDF
	incf	FSR,f
	btfss	FSR,7
	goto	$-3
	goto	NEXT

But how I call a TABLE to move all literal values to appropriate registers? (My literal values are in the table)

Thanks a lot

 

[bananasiong]

	movlw	11h
	movwf	FSR
NEXT	call        table
	movwf    INDF
	incf	FSR,f
	btfss	FSR,7
	goto	NEXT

 

[Suraj143]

Hi thanks for your reply doesn’t it need a jump value for TABLE?

Another problem if my last GP register is 15h how to detect that.

It means the tables last value must move to this last GP register.
I have only 5 GP registers they are 11h,12h,13h,14h,15h
So after moving last literal value to 15h it must do other work.

How to detect the last 15h register?

Thanks a lot

 

[blueroomelectronics]

Are you trying to read a table from program memory into RAM?

 [LEFT] table addwf PC,f
       retlw [data] ;is the normal way to read a table on a 14bit PIC core.[/LEFT]

you call it with

    call table ;(where W is the pointer to the table)

 

[Suraj143]

Ok thanks but how I detect the last value has reached that is 15h?

After moving the last literal value in the table to 15h I want to do other work.

So how can I detect the 15h GP register?

 

[blueroomelectronics]

increment the pointer value at the end of the loop and do a
btfsc pointer,4
goto exit

 

[Suraj143]

Is this Correct

	movlw	11h
	movwf	FSR
LOOP	call    table
	movwf   INDF
	incf	FSR,f
	[B]btfss	FSR,4[/B]
	goto	LOOP
	goto	EXIT

 

[bananasiong]

Ya, replace

	btfss	FSR,7
	goto	NEXT

with

	btfss	FSR,4
	goto	NEXT
	;do other thing here

 

[bananasiong]

You posted it first. That's right.

 

[Suraj143]

If there is below 8 GP registers its ok. If there is 10 registers how can I detect the last GP register?

Btfss FSR,???

 

[bananasiong]

No, not only 8 general purpose register. Up to 256 general purpose register maximum.
For example, after incf FSR, f

movf     FSR, w
xorlw     0x1b       ;if you start with 11h and you have 10 GP register,
                         ;the last one will be 1ah
btfss     STATUS, Z
goto      NEXT
goto      exit

 

[Suraj143]

Wow that’s great man that’s the one I need. So I can put your code into my program.

Thanks a lot

You are excellent

 

[Suraj143]

So here is the final coding moved table values to GP registers from 11h to 15h.

	movlw	11h
	movwf	FSR
LOOP	call    table
	movwf   INDF
	incf	FSR,f
	movf    FSR, w
	xorlw   16h     ;test if it is 16h GP register?
	btfss   STATUS, Z
	goto    LOOP
	goto    exit