Floating Point Division

[Fusillade]

Compiler Version: 4.047
Device: 18F2520

I'm new to the CCS compiler. I've been reading through the forum for about an hour to see if this is covered but I can not find the issue. I wanted to test the capabilities of floating point division of the compiler and PIC. I set up the following scenario:

float f_result;
float f_numerator;
float f_denominator;

f_numerator = 10.0;
f_denominator = 10.0;

f_result = 10.0 / 10.0;
f_result = f_numerator/10.0;
f_result = 10.0/f_denominator;
f_result = f_numerator/f_denominator;

When I step through the program, f_numerator and f_denominator are initialized to 10.0000000. The first division results in f_result having the value of 1.00000000. The next division gives me an error and the value is "out of scope".

I'm assuming the complier performed the pre-calculation of the 10.0/10.0 so it was not handled by the device. The second division was the first one performed by the device and it failed.

I checked the EX_FLOAT.C example and they define:

float a, b;

then perform:

printf("\r\na / b = %E\r\n", a / b);

Must floating point division be handled in another manner? Is this just a problem when stepping through the program?

Thanks.

[PCM programmer]

You didn't say what tool you're using to step through the code,
so I assume you're using MPLAB.

I installed PCH vs. 4.047 and compiled the test program shown below.
I then stepped through the code by pressing the F8 key, while observing
the C source code window. The cursor stopped on each line, and then
advanced to the next line, each time I pressed the F8 key. There were
no problems. I used MPLAB vs. 7.41, and I used the Configure menu
to select 18F2520 as the device before I compiled. I also used the
Debugger menu to select MPLAB SIM as the debugger.

I setup a Watch Window, and selected f_result as the variable to
watch. I right-clicked on Properties and made sure that the format
for f_result was 'MCHP Float'. Once I started stepping through the
code, it always gave the result as 1.00000000, and never said 'out of
scope'. It only said that at the beginning, before I started stepping.

Here is the test program:

[Fusillade]

Yes, I am using MPLAB v7.60.

To make all things equal, I copied your program and I still experienced the same problem. Then I noticed something in your post that made me think of something else.

From the MPLAB manual: