Making PBP code more modular

**Darrel Taylor** · - 26th July 2005, 22:46

I think the same thing applies there too. If TMR1_ON = %00000001, and the next person is trying to use an external crystal on timer1. It can cause problems.

Apparently I do things different than everyone else, but I try to do things in as Low Level as possible when controling SFR's.

This is also where Includes can come in handy.
In that file you can have predefined macro's that give good names to common functions. For the above example it might look like this...

Code:

ASM
TMR1_ON  macro
    bsf  T1CON, TMR1ON
    endm

TMR1_OFF  macro
    bcf  T1CON, TMR1ON
    endm
ENDASM

Along with many other Timer related macro's.

Then in the main program, you no longer need to worry about what registers, and what bit's need to be in a Magic Number or an Aliased variable. Just call the macro like this...

Code:

@  TMR1_ON

'-- OR --

@  TMR1_OFF

As a side benefit, those macros only take 1 instruction cycle, instead of the 2 required to copy a constant to a byte variable.

I don't think the buffer_size example applies here because it's not a bitwise operation. It's a whole number that still requires a constant. (CON, not =)

Darrel

**Darrel Taylor** · - 26th July 2005, 23:03

OR ---

Here's another version that allows you to work with Timers 0-3

Code:

ASM
TMR_ON  macro T
    if (T==0)
        bsf  T0CON, TMR0ON
    else
        if (T==1)
            bsf  T1CON, TMR1ON
        else
            if (T==2)
                bsf T2CON, TMR2ON
            else
                if (T==3)
                    bsf T3CON, TMR3ON
                endif
            endif
        endif
    endif
    endm

TMR_OFF  macro T
    if (T==0)
        bcf  T0CON, TMR0ON
    else
        if (T==1)
            bcf  T1CON, TMR1ON
        else
            if (T==2)
                bcf T2CON, TMR2ON
            else
                if (T==3)
                    bcf T3CON, TMR3ON
                endif
            endif
        endif
    endif
    endm
ENDASM

This still only takes 1 instruction cycle but allows you to select which timer is being used.

Code:

@  TMR_ON  1
@  TMR_ON  3
@  TMR_OFF 0

After awhile, your include files start to define your own personal language. No longer stuck with the standard commands that are defined in the PBP compiler. You'll spend a lot less time looking at the datasheets, and more looking at your program.

Best regards,
   Darrel

forgie · - 27th July 2005, 05:51

Now this is more like what includes make sense for (in my mind)..... Peripheral control macros. You could make a file that contains all the macros for one uC (e.g. 18f452.pbp). Every time you use a peripheral, you make a macro and add it to the uCs peripheral macro file. I was going to make another post asking about how to do assembly macros (I too want my own command set to make things tidier) but seeing your example shows me what I need to know.

Only one question: is there any way to make a macro in asm, then put PBP code inside the macro? (I guess I could go and pick the PBP-ASM files apart to find the ASM macros that PBP uses and use them, but if I don't have to I won't waste my time)

So, for example, is there some way to write, say an LCD command macro that uses LCDOUT?
so that
LCDCMD Clear, Line1, Right
would have the effect of
LCDOUT $FE, $01, $FE, $80, $FE, $14

(BTW I already have constants representing all those commands anyway, but it would be nice to not have to enter the them all in this way)

**Darrel Taylor** · - 27th July 2005, 07:02

You might want to try making includes NOT processor specific. Otherwise you go back to that multiple version problem again. If you need a new file for every chip you use, you'll be writing include files for ever.

is there any way to make a macro in asm, then put PBP code inside the macro?

Sure, you can pop in and out of asm whenever you want, but passing arguments can be a little trickier. Let's go back to the first example

Code:

ASM
TMR1_ON  macro
    bsf  T1CON, TMR1ON
    endm

TMR1_OFF  macro
    bcf  T1CON, TMR1ON
    endm
ENDASM

This could also be done this way

Code:

ASM
TMR1_ON  macro
    ENDASM
    T1CON.0 = 1     ' PBP statement in a macro
    ASM
    endm

TMR1_OFF  macro
    ENDASM
    T1CON.0 = 0
    ASM
    endm
ENDASM

But, as you can see, it's harder to read that way, but will compile to the exact same thing.

so that LCDCMD Clear, Line1, Right would have the effect of LCDOUT $FE, $01, $FE, $80, $FE, $14

Let's try the LCD thing with PBP statements too. This may not be the most efficient way to handle the LCD, but it does answer the specific question...

Code:

Clr       CON    1  system
Home      CON    2  system
Line1     CON    4  system
Line2     CON    8  system
Line3     CON   16  system
Line4     CON   32  system
CurOFF    CON   64  system
CurBlink  CON  128  system
CurUL     CON  256  system

ASM
LCDCMD  macro  options
    if (options & Clr) > 0      ; Clear Screen
        ENDASM
        LCDOUT  $FE, $01
        ASM
    endif
    if (options & Home) > 0     ; Home Cursor
        ENDASM
        LCDOUT  $FE, $02
        ASM
    endif
    if (options & Line1) > 0    ; Move to Line 1
        ENDASM
        LCDOUT  $FE, $80
        ASM
    endif
    if (options & Line2) > 0    ; Move to Line 2
        ENDASM
        LCDOUT  $FE, $C0
        ASM
    endif
    if (options & Line3) > 0    ; Move to Line 3
        ENDASM
        LCDOUT  $FE, $90         ; may be $94 on some displays
        ASM
    endif
    if (options & Line4) > 0    ; Move to Line 4
        ENDASM
        LCDOUT  $FE, $D0         ; may be $D4 on some displays
        ASM
    endif
    if (options & CurOFF) > 0   ; Turn Off Cursor
        ENDASM
        LCDOUT  $FE, $0C
        ASM
    endif
    if (options & CurBlink) > 0 ; Blinking Cursor
        ENDASM
        LCDOUT  $FE, $0F
        ASM
    endif
    if (options & CurUL) > 0    ; Underline Cursor
        ENDASM
        LCDOUT  $FE, $0E
        ASM
    endif
    endm
ENDASM

Then to use the macro you can do it this way...

Code:

@ LCDCMD Clr + CurBlink       ; Clear screen and turn on blinking cursor
'-- OR --
@ LCDCMD Clr + Line2 + CurOFF ; Clr screen, Move to Line2 and turn off cursor

Any of the options can be combined together, and only the options you use will actually create code.

HTH,
   Darrel

**mister_e** · - 27th July 2005, 15:47

Many thanks Darrel for this tutorial about the Macro. I guess it could be interesting to place a post in the FAQ or Code example on that AND how to work with the internal PBP macro also work... you know those MOVE?CB etc...

I could start it myself but... oooooh... you're really better than me to explain those

Well just an idea!

forgie · - 27th July 2005, 17:17

Thanks heaps for the info, Darrel, much appreciated.

With the LCD example, I was actually thinking more along the lines of how would one get a macro that can handle a list of arguments, like LCDOUT does. It's by no means a necessity, the workarounds are very easy, it would just be nice luxury to have in the world of coding.

Is it possible to do for loops in macros? e.g. make a macro called LCDRIGHT x which moves the cursor right x spaces, and define it using a for loop? Sorry, I don't know how to display code on this forum, so I can't write down the code for what I'm thinking of.

Anyway,
Thanks heaps for the info,
Nick

**mister_e** · - 27th July 2005, 17:41

Forgie,

to display code you must use those VbCode... really easy to use and explain Here

**Darrel Taylor** · - 27th July 2005, 20:00

Originally Posted by forgie

With the LCD example, I was actually thinking more along the lines of how would one get a macro that can handle a list of arguments, like LCDOUT does.

Well, I thought that's what it does. It takes a list of arguments, but instead of using commas, it uses the Plus sign instead.

Take a look at this thread Embedded Strings in your Code Space
It has some more examples of passing parameters with macro's.

But really, the main problem is that MPASM always has to have the exact number of parameters supplied to a macro. So a single macro can't accept 2 parameters on 1 use and 5 on another. PM has that ability, but I don't like making programs that only work with PM since you can't use it with the 18F's

Originally Posted by forgie

Is it possible to do for loops in macros? e.g. make a macro called LCDRIGHT x which moves the cursor right x spaces, and define it using a for loop?

Yes, you can do that. But keep in mind that every time you use a macro, it duplicates the entire code at the place where it is used. So, big macro's that are used several times can eat up a lot of code space. There are ways around that too, but it's not for the scardy cats. For instance, consider this example as an alternative to the LCDRIGHT idea. It allows you to move the cursor anywhere on the screen using either constants or byte variables. Using the constant version would look like this

Code:

@ LCDCUR?C 1,5  ; Row, Col

Which would move the cursor to Row1, Colomn5.

Or, using the byte variable version would be like this

Code:

Row  VAR BYTE  system
Col  VAR BYTE  system

Row = 2
Col = 10
@ LCDCUR?B  Row, Col

Here's the macros for them. They are self optimising, so that no code is generated unless you actually use them. The main parts of the routine are actually subroutines that can be "called", and the macros you use in the main program simply place the parameters in Temp variables so that the "called" routine can access them. This way it only uses a few words each time you use one of the macro's.

Code:

This code has been removed, please see a couple posts down for the revision.
Should have tested it first. Doh!

I just threw this together last night in anticipation of your next question, so if you actually try it, and have problems, let me know.

Best regards,
   Darrel

**Darrel Taylor** · - 28th July 2005, 03:50

Originally Posted by mister_e

... it could be interesting to place a post in the FAQ or Code example on that AND how to work with the internal PBP macro also work... you know those MOVE?CB etc...!

Yeah, probably would..., but I don't know, something about the FAQ section scares me.

If you choose a topic, then your supposed to answer all the frequently asked questions about that topic. It's like you're supposed to know everything about it, and you don't want to miss anything because nobody's going to write an FAQ that conflict's with you're FAQ.

Coupled with the fact that, I don't know Everything about Anything. It's just not a good fit for me.

But actually, I've tried to write something for the macro's in PBP 3 times now. Then when I read it back afterwards, it never seems to get the point across. Not even close.

I do think it's worthwhile to laud the abilities of INCLUDE macro's. Especially since nobody seems to use them. So maybe it's time for a new approach.

Hmmm, what could it be .... scratch, scratch ...

DT

**Darrel Taylor** · - 28th July 2005, 07:39

OK, so that last example was terrible. Should have tested it first.

Here's a better one that shows more of how to use PBP statements in macro's. It's also a little easier to see how the "self optimization" works. (this time I tested it)

Code:

<b>DEFINE  </b></font><b>LCDCOLS 16  </b><font color="#0000FF"><b><i>; can be 8, 16, 20, 24 or 40
                    ; but 20 is the only one that matters in this routine
</i></b></font><b>LCD_Row   </b><font color="#008000"><b>VAR BYTE </b></font><b>system
LCD_Col   </b><font color="#008000"><b>VAR BYTE </b></font><b>system

</b><font color="#008000"><b>ASM
    </b></font><font color="#000080">ifndef LCDCOLS
        #define LCDCOLS 16    </font><font color="#0000FF"><b><i>; Default to 16 Columns
    </i></b></font><font color="#000080">endif

MoveCursorExpanded = 0


</font><font color="#0000FF"><b><i>; --- Move cursor to new location ---(inputs are LCD_Row and LCD_Col)-----------
</i></b></font><font color="#000080">Expand_MoveCursor  macro
  local  OverCode
    goto      OverCode
MoveCursorExpanded = 1
MoveCursor
    if LCDCOLS == 20          </font><font color="#0000FF"><b><i>; if using a 4x20 display
        </i></b></font><font color="#008000"><b>ENDASM
            LOOKUP </b></font><b>LCD_Row</b>,[<b>$80</b>,<b>$80</b>,<b>$C0</b>,<b>$94</b>,<b>$D4</b>],<b>LCD_Row
        </b><font color="#008000"><b>ASM
    </b></font><font color="#000080">else                      </font><font color="#0000FF"><b><i>; if NOT using a 4x20 display
        </i></b></font><font color="#008000"><b>ENDASM
            LOOKUP </b></font><b>LCD_Row</b>,[<b>$80</b>,<b>$80</b>,<b>$C0</b>,<b>$90</b>,<b>$D0</b>],<b>LCD_Row
        </b><font color="#008000"><b>ASM
    </b></font><font color="#000080">endif
    </font><font color="#008000"><b>ENDASM
        </b></font><b>LCD_Row </b>= <b>LCD_Row </b>+ (<b>LCD_Col </b>- <b>1</b>)
        <font color="#008000"><b>LCDOUT </b></font><b>$FE</b>, <b>LCD_Row  </b><font color="#0000FF"><b><i>; Send the command
    </i></b></font><font color="#008000"><b>ASM
    </b></font><font color="#000080">return
OverCode
    endm

</font><font color="#0000FF"><b><i>; --- Move LCD cursor to  Row, Column using constants --------------------------
</i></b></font><font color="#000080">LCDCUR?C  macro  Row, Col
    if MoveCursorExpanded == 0
        Expand_MoveCursor
    endif
    MOVE?CB   Row, LCD_Row
    MOVE?CB   Col, LCD_Col
    L?CALL    MoveCursor
    endm

</font><font color="#0000FF"><b><i>; --- Move LCD cursor to  Row, Column using Byte variables ---------------------
</i></b></font><font color="#000080">LCDCUR?B  macro  Row, Col
    if MoveCursorExpanded == 0
        Expand_MoveCursor
    endif
    MOVE?BB   Row, LCD_Row
    MOVE?BB   Col, LCD_Col
    L?CALL    MoveCursor
    endm

</font><font color="#008000"><b>ENDASM
</b></font>

Using them is still the same

Code:

<font color="#000080">@ LCDCUR?C 1,5          </font><font color="#0000FF"><b><i>; Move to Row1 Column5
  </i></b></font><font color="#008000"><b>LCDOUT </b></font><font color="#FF0000">&quot;R1C5&quot;         </font><font color="#0000FF"><b><i>; Display something

'-- OR --

</i></b></font><b>Row  </b><font color="#008000"><b>VAR BYTE  </b></font><b>system
Col  </b><font color="#008000"><b>VAR BYTE  </b></font><b>system

Row </b>= <b>2
Col </b>= <b>10
</b><font color="#000080">@ LCDCUR?B  Row, Col    </font><font color="#0000FF"><b><i>; Move to Row2 Column10
  </i></b></font><font color="#008000"><b>LCDOUT </b></font><font color="#FF0000">&quot;R2C10&quot;        </font><font color="#0000FF"><b><i>; Display something</i></b></font>

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