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Piclist Code help pls

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D

dons21

New Member
Hi, I am playing with different multiply codes from the piclist.com site and I am stuck with this one.


I have all the correct memory files but I just don't know how to get the code running. I have tried calling and goto, But I am stuck now.

Cheers

Don
 
Here it is
Code: 
; Multiply 10bit by 10bit unsigned
;  by Martin Sturm  2010
; Tested over full range of 10bit input combinations
;
;   a (10bit) = aH:aL   (not modified)
;   b (10bit) = bH:bL   (not modified)
;   aH:aL * bH:bL --> rH:rM:rL
;
; incorrect result if a or b has non-zero bits above the 10th
;  unless optional ANDLW 0x03 is used
;
; Algorithm
;  r = a*b
;  r = 2^16*(aH*bH) + 2^8*(aH*bL + bH*aL) + aL*bL
;             2x2           2x8     2x8      8x8
; all multiplications are unrolled
;
;  73 instructions, 57-73 cycles, 65 avg
;

; helper macro
mmac MACRO A,bit, uH,uL
	BTFSC	A,bit
	 ADDWF	uH,F
	RRF	uH,F
	RRF	uL,F
	ENDM

MULT_10x10 MACRO aH,aL, bH,bL, rH,rM,rL
 LOCAL g1, g2, g3, g4

	; rM:rL = aL*bL   [8x8 bit multiply] (36 cycles)
	CLRF	rM
	CLRF	rL
	CLRC
	MOVFW	bL
	mmac	aL,0, rM,rL
	mmac	aL,1, rM,rL
	mmac	aL,2, rM,rL
	mmac	aL,3, rM,rL
	mmac	aL,4, rM,rL
	mmac	aL,5, rM,rL
	mmac	aL,6, rM,rL
	mmac	aL,7, rM,rL

	; rH = aH*bH   [2x2 bit multiply] (8 cycles)
	CLRF	rH
	MOVFW	bH	; multiplicand in W
;	ANDLW	0x03	; prevent errors if bH non-zero above 10th bit
	BTFSC	aH,1	; carry always clear by here
	 ADDWF	rH,F	; never sets carry
	RLF	rH,F
	BTFSC	aH,0
	 ADDWF	rH,F

	; rH:rM += aH*bL  [2-bit x 8-bit] (7-15 cycles, avg 11)
	MOVFW	bL	; multiplicand in W
	BTFSS	aH,0
	 GOTO	g1
	ADDWF   rM,F	; add bL
	SKPNC
	 INCF	rH,F
g1
	BTFSS	aH,1
	 GOTO	g2
	CLRC
	RLF     bL,W	;  W now holds (2*bL & 0xFF)
	ADDWF   rM,F	; add W to rM
	SKPNC
	 INCF	rH,F
	BTFSC	bL,7	;
	 INCF	rH,F	; add the upper bit of 2*bL
g2

	; rH:rM += bH*aL  [2-bit x 8-bit] (7-15 cycles, avg 11)
	MOVFW	aL	; multiplicand in W
	BTFSS	bH,0
	 GOTO	g3
	ADDWF   rM,F	; add aL
	SKPNC
	 INCF	rH,F
g3
	BTFSS	bH,1
	 GOTO	g4
	CLRC
	RLF     aL,W	;  W now holds (2*aL & 0xFF)
	ADDWF   rM,F	; add W to rM
	SKPNC
	 INCF	rH,F
	BTFSC	aL,7	;

	 INCF	rH,F	; add the upper bit of 2*aL
g4

	ENDM


But we also need the OP code to see how he is using the macro
 
Last edited:
I am just messing with MPLAB SIM trying different multiply routines I.

Here I just want to multiply 1023 by 2 or what ever I choose.


Code: 
    LIST      p=16F88              ; list directive to define processor
    #INCLUDE <P16F88.INC>          ; processor specific variable definitions
	ERRORLEVEL	0,	-302		   ;suppress bank selection messages
;------------------------------------------------------------------------------
; CONFIGURATION WORD SETUP
;------------------------------------------------------------------------------

	__CONFIG _CONFIG1, _CP_OFF & _CCP1_RB0 & _DEBUG_OFF & _WRT_PROTECT_OFF & _CPD_OFF & _LVP_OFF & _BODEN_OFF & _MCLR_ON & _PWRTE_OFF & _WDT_OFF & _INTRC_IO
    __CONFIG _CONFIG2, _IESO_OFF & _FCMEN_OFF


	CBLOCK	0x20 				 ;GPR variable registers allocated contiguously
   		aH
		aL
		bH
		bL
		rH
		rM
		rL
	ENDC


RESET	ORG     0x0000            ; processor reset vector


 	  
 	  	bsf 	STATUS,		RP0	;select bank 1
		movlw	0x07
		movwf	CMCON			;turn comparators off 
  	 
	   
		movwf	OSCCON			;
		movlw	b'00010011'		;set ra2&3 to digital & RB6 & 7 !!
		movwf	ANSEL
		movlw	b'1110011'		;set RA2&3 to output
		movwf	TRISA
		
		movlw 	b'00000000'		;set PortB all outputs
		movwf 	TRISB
		movlw	b'01100000'		;Set up clock speed mhz4
		movlw	b'01000000'
		movlw	ADCON1
		bcf		STATUS,		RP0
		movlw	b'01001001'
		movwf	ADCON0
		clrf	PORTA
		clrf	PORTB	
		bsf		PORTA,2
		goto    START             ; go to beginning of program



START
		movlw	b'11111111'
		movwf	aH
		movlw	b'11000000'
		movwf 	aL
		movlw	.2
		movwf	bL
		Call	Times
		goto START




;CODE FROM PICLIST.COM		
; Multiply 10bit by 10bit unsigned
;  by Martin Sturm  2010
; Tested over full range of 10bit input combinations
;
;   a (10bit) = aH:aL   (not modified)
;   b (10bit) = bH:bL   (not modified)
;   aH:aL * bH:bL --> rH:rM:rL
;
; incorrect result if a or b has non-zero bits above the 10th
;  unless optional ANDLW 0x03 is used
;
; Algorithm
;  r = a*b
;  r = 2^16*(aH*bH) + 2^8*(aH*bL + bH*aL) + aL*bL
;             2x2           2x8     2x8      8x8
; all multiplications are unrolled
;
;  73 instructions, 57-73 cycles, 65 avg
;

; helper macro
mmac MACRO A,bit, uH,uL
	 BTFSC	A,bit
	 ADDWF	uH,F
	 RRF	uH,F
	 RRF	uL,F
 ENDM



MULT_10x10 MACRO aH,aL, bH,bL, rH,rM,rL
 	LOCAL g1, g2, g3, g4

	; rM:rL = aL*bL   [8x8 bit multiply] (36 cycles)		CLRF	rM
	CLRF	rL
	CLRC
	MOVFW	bL
	mmac	aL,0, rM,rL
	mmac	aL,1, rM,rL
	mmac	aL,2, rM,rL
	mmac	aL,3, rM,rL
	mmac	aL,4, rM,rL
	mmac	aL,5, rM,rL
	mmac	aL,6, rM,rL
	mmac	aL,7, rM,rL

	; rH = aH*bH   [2x2 bit multiply] (8 cycles)
	CLRF	rH
	MOVFW	bH	; multiplicand in W
	ANDLW	0x03	; prevent errors if bH non-zero above 10th bit
	BTFSC	aH,1	; carry always clear by here
	 ADDWF	rH,F	; never sets carry
	RLF	rH,F
	BTFSC	aH,0
	 ADDWF	rH,F

	; rH:rM += aH*bL  [2-bit x 8-bit] (7-15 cycles, avg 11)
	MOVFW	bL	; multiplicand in W
	BTFSS	aH,0
	 GOTO	g1
	ADDWF   rM,F	; add bL
	SKPNC
	 INCF	rH,F
g1
	BTFSS	aH,1
	 GOTO	g2
	CLRC
	RLF     bL,W	;  W now holds (2*bL & 0xFF)
	ADDWF   rM,F	; add W to rM
	SKPNC
	 INCF	rH,F
	BTFSC	bL,7	;
	 INCF	rH,F	; add the upper bit of 2*bL
g2

	; rH:rM += bH*aL  [2-bit x 8-bit] (7-15 cycles, avg 11)
	MOVFW	aL	; multiplicand in W
	BTFSS	bH,0
	 GOTO	g3
	ADDWF   rM,F	; add aL
	SKPNC
	 INCF	rH,F
g3
	BTFSS	bH,1
	 GOTO	g4
	CLRC
	RLF     aL,W	;  W now holds (2*aL & 0xFF)
	ADDWF   rM,F	; add W to rM
	SKPNC
	 INCF	rH,F
	BTFSC	aL,7	;
	 INCF	rH,F	; add the upper bit of 2*aL
g4

	ENDM
   
 
	GOTO$	

	END
 
be80be,

I almost understand how it works, but need help with the macro ??? thats where i am stuck.
 
Last edited:
Here a hint
Note: Macros must be defined before they are used, i.e., forward references to macros are not permitted
Click to expand...


macro - Declare Macro Definition
Syntax
label macro [arg, ..., arg]
Description
A macro is a sequence of instructions that can be inserted in the assembly source code by using a single macro call. The macro must first be defined, then it can be referred to in subsequent source code.

Arguments are read in from the source line, stored in a linked list and then counted. The maximum number of arguments would be the number of arguments that would fit on the source line, after the label and macro terms. Therefore, the maximum source line length is 200 characters.

A macro can call another macro, or may call itself recursively. The maximum number of nested macro calls is 16.
 
Last edited:
Look this over i think it will help you

Code: 
This code demonstrates the utility of macro directive, which is used to define a macro. 

  #include p16f877a.inc  ;Include standard header file
                         ;for the selected device.

result  equ  0x20        ;Assign value 20H to label
                         ;result.

  ORG  0x0000            ;The following code will be placed
                         ;in reset address 0.
  goto  start            ;Jump to an address whose label is
                         ;'start'.

add  MACRO  num1,num2    ;'add' is a macro. The values of
                         ;'num1' and 'num2' must be passed
                         ;to this macro.

  movlw  num1            ;Load W register with a literal
                         ;value assigned to the label
                         ;'num1'.

  movwf  result          ;Load W register to an address
                         ;location assigned to the label
                         ;'result'.

  movlw  num2            ;Load W register with a literal
                         ;value assigned to the label
                         ;'num2'.

  addwf  result          ;Add W register with the memory
                         ;location addressed by 'result'
                         ;and load the result back to
                         ;'result'.

  endm                   ;end of 'add' MACRO

  ORG  0x0010            ;Main program starts at 10H.

start                    ;The label 'start' is assigned an
                         ;address 10H.

  add  .100,.90          ;Call 'add' MACRO with decimal
                         ;numbers 100 and 90 assigned to
                         ;'num1' and 'num2' labels, 
                         ;respactively. 100 and 90 will be
                         ;added and the result will be in
                         ;'result'.

  end


One more hint your macro can be placed in a file by itself Or place inline at the start of your main code
 
Last edited:
I suspect you're messing up the hi and lo portions of the aH:aL register pair and the hi portion of the bH:bL register pair. You might try something like this;

Regards, Mike

Code: 
        radix   dec
START
        movlw   low(1023)       ;
        movwf   aL              ;
        movlw   high(1023)      ;
        movwf   aH              ;
        movlw   low(2)          ;
        movwf   bL              ;
        movlw   high(2)         ;
        movwf   bH              ;
        call    Times           ;
        goto    $               ;
Another way to do exactly the same thing;
Code: 
        radix   dec
START
        movlw   1023%256        ; a = 1023
        movwf   aL              ;
        movlw   1023/256        ;
        movwf   aH              ;
        movlw   2%256           ; b = 2
        movwf   bL              ;
        movlw   2/256           ;
        movwf   bH              ;
        call    Times           ; do 10x10 multiply
        goto    $               ;
 
Last edited:
Thanks for the pointers I understand how the macro is supposed to work now. But I am still stuck. say I want to do 1023x1023


MULT_10x10 b'00000011',b'11111111', b'00000011,b'11111111', rH,rM,rL

is that correct?
 
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