Correct Behavior of long int (int16)?

[Keith Ward]

I am using an older version of the PCM compiler (2.674) but the newer ones may function the same way. When defining a long and then assigning various values the long appears to work correctly but when attempting to increment a long (e.g. count++) only the lower byte gets updated and it functions as though it were just an int (int8). Is this a bug or a feature?!
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This message was ported from CCS's old forum
Original Post ID: 13284

[Steve H.]

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This message was ported from CCS's old forum
Original Post ID: 13286

[PCM programmer]

:=I am using an older version of the PCM compiler (2.674) but the newer ones may function the same way. When defining a long and then assigning various values the long appears to work correctly but when attempting to increment a long (e.g. count++) only the lower byte gets updated and it functions as though it were just an int (int8). Is this a bug or a feature?!
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I installed PCM vs. 2.674 and it works OK for me.

The following sample program has this output:

12fe
12ff
1300
1301


<PRE>
#include "c:\picc\test\16F877.H"
#fuses HS, NOWDT, NOPROTECT, PUT, BROWNOUT, NOLVP
#use Delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
<BR>
//====================================================
void main()
{
long k;
<BR>
<BR>
k = 0x12FE;
printf("\%lx\n\r", k);
k++;
printf("\%lx\n\r", k);
k++;
printf("\%lx\n\r", k);
k++;
printf("\%lx\n\r", k);
<BR>
<BR>
while(1);
}
</PRE>
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This message was ported from CCS's old forum
Original Post ID: 13290

[Jerry Finsen]

I have recently reported a related problem. I have a program that has a statement in the form:

X += Y * Z that does not work, while the form X = X + (Y * Z) does work. All variables unsigned int16. Errors on the first form appear after 255 is reached. Below that all is OK. The errors are not consistant at 255, sometimes 260-280 -- I really don't understand that.
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This message was ported from CCS's old forum
Original Post ID: 13293

[Keith Ward]

Ok, here it is. As much as I hate to admit it the sanity checks from all of your responses told me it was not a bug. The problem was that I'm using a 16C84 and not a 16F84 ... that alone fixed it!

I hate it when this sort of thing creeps in. It really keeps you from the "real" project. I really should learn when I'm too tired to work on things and just go to bed!


:=I am using an older version of the PCM compiler (2.674) but the newer ones may function the same way. When defining a long and then assigning various values the long appears to work correctly but when attempting to increment a long (e.g. count++) only the lower byte gets updated and it functions as though it were just an int (int8). Is this a bug or a feature?!
___________________________
This message was ported from CCS's old forum
Original Post ID: 13299