Instant Interrupt Error

[cool_justin]

Hi,

I recently got Darrel Taylor's 'Instant Interrupt' program to work and was trying to integrate into my main program. However, I get the error below:

"Temp variables exceeding T4"

I looked in ReEnterPBP.bas and found that it was the file that was reporting back the error (see the relevant section of code below).

I do use a lot of variables in my program, but the total is 110 bytes, far from the 368 bytes on the 16F877a.

Does anyone know of a way to modify the ReEnterPBP code so that it is able to save more variables (I should have the RAM space...)?


From ReEnterPBP.bas:


ASM
ifdef RS1
MOVE?BB _RS1_Save, RS1
endif
ifdef RS2
MOVE?BB _RS2_Save, RS2
endif
ifdef T1
MOVE?WW _T1_Save, T1
endif
ifdef T2
MOVE?WW _T2_Save, T2
endif
ifdef T3
MOVE?WW _T3_Save, T3
endif
ifdef T4
MOVE?WW _T4_Save, T4
endif
ifdef T5
ERROR "Temp variables exceeding T4"
endif
ENDASM

Thanks!!
Justin

[Darrel Taylor]

Hi Justin,

PBP creates temporary variables as needed to handle complex formula's.

<pre>x =((x*2)+3) + (y*2+1)/$4+(z+1)*2+(d*/250*2)+m dig 2</pre>For the above formula, PBP will need 5 temporary vars. (T1-T5) The more complex the formula, the more temp vars that are needed.

Correcting the problem can be done 2 different ways.

<hr>1. Break the formula into smaller sections. Changing the above formula to something like this ...<pre>x =((x*2)+3) + (y*2+1)/$4+(z+1)*2<br>x = x +(d*/250*2)+m dig 2</pre>will reduce the number of temp vars required to 3, which will fit into the existing program.

<hr>2. Modify the ReEnterPBP file to handle more Temp vars.

For each additional temp variable, create a new place to save it..
<pre> T5_Save VAR WORD</pre>In the SavePBP: routine, add a condition to save the variable.<pre> ifdef T5<br> MOVE?WW T5, _T5_Save<br> endif</pre>And in the RestorePBP: routine, add a condition to restore the variable.<pre> ifdef T5<br> MOVE?WW _T5_Save, T5<br> endif</pre>Then adjust the error message to trigger at a higher number.<pre> ifdef T6<br> ERROR "Temp variables exceeding T5"<br> endif</pre>Repeat, untill you no longer get an error.

HTH,
Darrel

[cool_justin]

Darrel,

It works great now - thanks as always for your contributions to the PBP community!

Justin