Multiple if then optimization

[Darrel Taylor]

It's monday! What'd you expect?
Wait 'till DT comes online...
Figure maybe down to...what...25 words total?

Thanks for the vote of confidence ski.

But sadly, all I could muster was a slim 335 words

<font color="#000000"><b>CMCON </b>= <font color="#800000"><b>7                </b></font><font color="#0000FF"><b><i>' Disable Comparators

</i></b></font><font color="#008000"><b>DEFINE </b></font><b>DEBUG_BAUD </b><font color="#800000"><b>2400   </b></font><font color="#0000FF"><b><i>'Debug baud rate 
</i></b></font><font color="#008000"><b>DEFINE </b></font><b>DEBUGIN_REG PORTB </b><font color="#0000FF"><b><i>'Debugin pin port 
</i></b></font><font color="#008000"><b>DEFINE </b></font><b>DEBUGIN_BIT </b><font color="#800000"><b>0     </b></font><font color="#0000FF"><b><i>'Debugin pin bit 
</i></b></font><font color="#008000"><b>DEFINE </b></font><b>DEBUGIN_MODE </b><font color="#800000"><b>1    </b></font><font color="#0000FF"><b><i>'Debugin mode: 0 = True, 1 = Inverted 

</i></b></font><b>Uin       </b><font color="#008000"><b>VAR WORD
</b></font><b>B0        </b><font color="#008000"><b>VAR BYTE 
</b></font><b>BarCount  </b><font color="#008000"><b>VAR BYTE
</b></font><b>BarValue  </b><font color="#008000"><b>VAR WORD
</b></font><b>MsgAddr   </b><font color="#008000"><b>VAR WORD
</b></font><b>Carry     </b><font color="#008000"><b>VAR </b></font><b>STATUS</b>.<font color="#800000"><b>0        </b></font><font color="#0000FF"><b><i>; Hardware carry flag

</i></b></font><font color="#008000"><b>GOTO </b></font><b>Main                     </b><font color="#0000FF"><b><i>; Jump over data
;=============================================================================
 </i></b></font><b>BarSteps</b>:  <b>POKECODE   </b><font color="#800000"><b>10</b></font>,<font color="#800000"><b>15</b></font>,<font color="#800000"><b>19</b></font>,<font color="#800000"><b>24</b></font>,<font color="#800000"><b>29</b></font>,<font color="#800000"><b>34</b></font>,<font color="#800000"><b>43</b></font>,<font color="#800000"><b>53</b></font>,<font color="#800000"><b>62</b></font>,<font color="#800000"><b>72</b></font>,<font color="#800000"><b>81</b></font>,<font color="#800000"><b>86</b></font>,<font color="#800000"><b>91</b></font>,<font color="#800000"><b>96</b></font>,<font color="#800000"><b>100</b></font>,<font color="#800000"><b>105
</b></font><b>_BarSteps   </b><font color="#008000"><b>CON </b></font><b>EXT           </b><font color="#0000FF"><b><i>; create a PBP constant that points to the Table

 </i></b></font><b>TooLow</b>:  <b>POKECODE </b><font color="#800000"><b>$FE</b></font>,<font color="#800000"><b>1</b></font>,<font color="#FF0000">&quot;TOO LOW &quot;</font>,<font color="#800000"><b>0
</b></font><b>_TooLow   </b><font color="#008000"><b>CON </b></font><b>EXT             </b><font color="#0000FF"><b><i>; PBP constant pointing to the &quot;Too Low &quot; string
  
 </i></b></font><b>TooRich</b>: <b>POKECODE </b><font color="#800000"><b>$FE</b></font>,<font color="#800000"><b>$C0</b></font>,<font color="#FF0000">&quot;TOO RICH&quot;</font>,<font color="#800000"><b>0
</b></font><b>_TooRich  </b><font color="#008000"><b>CON </b></font><b>EXT             </b><font color="#0000FF"><b><i>; PBP constant pointing to the &quot;Too Rich&quot; string
  
</i></b></font><b>FlashSize </b><font color="#008000"><b>CON </b></font><b>EXT
</b><font color="#008000"><b>ASM
   </b></font><font color="#000080">ifdef BSR
FlashSize = 2                 </font><font color="#0000FF"><b><i>; 18F has byte addressing (2)
   </i></b></font><font color="#000080">else
FlashSize = 1                 </font><font color="#0000FF"><b><i>; 12F/16F has words (1)
   </i></b></font><font color="#000080">endif
</font><font color="#008000"><b>ENDASM

</b></font><b>MidChar   </b><font color="#008000"><b>CON </b></font><b>EXT             </b><font color="#0000FF"><b><i>; MidChar is the border between
</i></b></font><font color="#000080">@MidChar = 8 * FlashSize      </font><font color="#0000FF"><b><i>; 8 char segments of the 1x16 LCD being used

;=============================================================================
</i></b></font><b>Main</b>:
    <font color="#008000"><b>DEBUGIN </b></font>[<b>Uin</b>.<b>LowByte</b>]     <font color="#0000FF"><b><i>; Serial Input
    </i></b></font><b>Uin </b>=  <b>Uin </b>*/ <font color="#800000"><b>124         </b></font><font color="#0000FF"><b><i>; same as (* 100 / 207)
    </i></b></font><font color="#008000"><b>LCDOUT </b></font><font color="#800000"><b>$FE</b></font>, <font color="#800000"><b>2             </b></font><font color="#0000FF"><b><i>; LCD Home Cursor

    </i></b></font><font color="#008000"><b>FOR </b></font><b>BarCount </b>= <font color="#800000"><b>0 </b></font><font color="#008000"><b>TO </b></font>(<font color="#800000"><b>15 </b></font>* <b>FlashSize</b>) <font color="#008000"><b>STEP </b></font><b>FlashSize
        </b><font color="#008000"><b>IF </b></font>(<b>BarCount </b>= <b>MidChar</b>) <font color="#008000"><b>THEN LCDOUT </b></font><font color="#800000"><b>$FE</b></font>,<font color="#800000"><b>$C0  </b></font><font color="#0000FF"><b><i>; Second half of 1x16 LCD
        </i></b></font><b>PEEKCODE </b>(<b>_BarSteps</b>+<b>BarCount</b>),<b>BarValue       </b><font color="#0000FF"><b><i>; Get BarValue from Table
        </i></b></font><b>R0</b>.<b>LowByte </b>= <b>Uin</b>.<b>LowByte </b>- <b>BarValue
        </b><font color="#008000"><b>IF </b></font><b>Carry </b><font color="#008000"><b>THEN                                </b></font><font color="#0000FF"><b><i>; Uin &gt;= BarValue
            </i></b></font><font color="#008000"><b>LCDOUT </b></font><font color="#800000"><b>255                               </b></font><font color="#0000FF"><b><i>;  show a Full char
        </i></b></font><font color="#008000"><b>ELSE                                         </b></font><font color="#0000FF"><b><i>; Uin &lt; BarValue
            </i></b></font><font color="#008000"><b>LCDOUT </b></font><font color="#FF0000">&quot; &quot;                               </font><font color="#0000FF"><b><i>;  show a blank
        </i></b></font><font color="#008000"><b>ENDIF
    NEXT </b></font><b>BarCount
    
    R0</b>.<b>LowByte </b>= <b>Uin</b>.<b>LowByte </b>- <font color="#800000"><b>10                    </b></font><font color="#0000FF"><b><i>; if Uin &lt; 10
    </i></b></font><font color="#008000"><b>IF </b></font>!<b>Carry </b><font color="#008000"><b>THEN </b></font><b>MsgAddr </b>= <b>_TooLow </b>: <font color="#008000"><b>GOSUB </b></font><b>ShowMsg

    R0</b>.<b>LowByte </b>= <b>Uin</b>.<b>LowByte </b>+ <font color="#800000"><b>145                   </b></font><font color="#0000FF"><b><i>; if Uin &gt; 110
    </i></b></font><font color="#008000"><b>IF </b></font><b>Carry </b><font color="#008000"><b>THEN </b></font><b>MsgAddr </b>= <b>_TooRich </b>: <font color="#008000"><b>GOSUB </b></font><b>ShowMsg
</b><font color="#008000"><b>GOTO </b></font><b>Main

</b><font color="#0000FF"><b><i>;=============================================================================
</i></b></font><b>ShowMsg</b>:
    <b>PEEKCODE MsgAddr</b>, <b>B0
    </b><font color="#008000"><b>IF </b></font><b>B0 </b>= <font color="#800000"><b>0 </b></font><font color="#008000"><b>THEN RETURN
    LCDOUT </b></font><b>B0
    MsgAddr </b>= <b>MsgAddr </b>+ <b>FlashSize
</b><font color="#008000"><b>GOTO </b></font><b>ShowMsg
</b>

cheers,

[Mugelpower]

Hi Darrel,

looks impressive to me like a motorcycle to a small boy.....

Whats this command:

Uin = Uin */ 124 ; same as (* 100 / 207)

|
|
|
the above means two mathematic orders in one? something like shifting bits?

there would be a small mistake but thats totally acceptable because the bargraph is that crude which is really fine enough.

will test that of course although there should be no need.....

regards

Mugel

[Darrel Taylor]

The */ operator first multiplies the 2 values (Uin * 124).
Then it discards the low byte, and returns the rest.
So effectively, it divides the result by 256, without having to do the divide part.

100 / 207 = 0.48309178
124 / 256 = 0.484375 ; not exact, but pretty close

You're correct that there are small differences between the 2 formulas, but the error is less than +/- 1. And, you will never see a difference with the resolution of a 16 block bargraph.

And, there probably is a need to test it.
I was using a 16F877 with a 4x20 LCD. Could have missed something for your 16F628A and 1x16 LCD.
<br>

[Acetronics2]

Hi, Darrel

Could you tell us for LCD Initialization at powerup ...If Uin first value is > 10 ... I do not see any ???

you just suppose exhaust is air filled ???

Alain

[Darrel Taylor]

I'm not sure what you mean Alain.

If the first value is > 10, it will just draw the bargraph like normal.
It doesn't do anything until a serial byte is received.
<br>

[Acetronics2]

I'm not sure what you mean Alain.

If the first value is > 10, it will just draw the bargraph like normal.
It doesn't do anything until a serial byte is received.
<br>

Hi,Darrel

What I ment is you initialize the LCD ... ONLY if the value is < 10 ... ( when writing TOO LOW )

What if you stop the engine and start it again ??? ... first value will be > 10 , due to the exhaust gases still in the exhaust tubing ... and I do not see any LCDOUT $FE,1 in this figure.

Alain

[skimask]

What if you stop the engine and start it again ??? ... first value will be > 10 , due to the exhaust gases still in the exhaust tubing ... and I do not see any LCDOUT $FE,1 in this figure.
Alain

Exhaust gases might still be in the tubing, but I wonder how quickly the sensor will cool off and not make a decent output. In my experience, those things cool off fairly quick. But then again, the 3/4 wire ones heat up pretty fast too...

[Darrel Taylor]

What I ment is you initialize the LCD ... ONLY if the value is < 10 ... ( when writing TOO LOW )

What if you stop the engine and start it again ??? ... first value will be > 10 , due to the exhaust gases still in the exhaust tubing ... and I do not see any LCDOUT $FE,1 in this figure.

Oh, you mean the "Clear Screen".
Since it writes to all 16 characters on each pass, I used "Home Cursor" ($FE,2) instead of "Clear Screen" ($FE,1) to prevent blinking of the display during updates.

Or, if you're referring to the Power-On initialization that gets rid of the black blocks and makes the LCD work in the first place .... Mugel didn't have any specific initialization sequences in his original program and reported it to be working. So I assumed his display didn't need it.

The first character sent to the LCD will cause PBP to initialize the display (if it hasn't already). It doesn't have to be $FE,1.
<br>