General Purpose Register question

[Boyce]

At the end of the 16F690 Special Function Register list is a set called General Purpose Register.
I am guessing that the general purpose register is used when variables are declared in C.
True?
If not, how is the General Purpose Register used?
Thanks,
Boyce
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[Ttelmah]

Almost....
This is the chip's RAM memory. It is used for _everything_ requiring dynamic data storage. Temporary values during arithmetic, storing copies of the special function registers during interrupts, storing copies of variables, when calling routines, and the variables themselves.
So, 'yes' this is where the variables go, but a lot of other stuff as well....

If you open the .LST file generated when you compile a program, at about the 7th line down, you will see a pair of lines, with the first starting, "RAM used:". This shows how much of the RAM is being used!.

The '.sym' file, gives the actual locations used for specific items.

It is almost a slight 'misprint' in the data sheet, since this is a block of 'General purpose registers' (note the plural), rather than a single 'General purpose register'. The sheet entry for the smallest processor has the plural, but it is omitted for the larger chips.....

Best Wishes

[Boyce]

[Ttelmah]

Yes.
This is one of the big advantages of using a compiler, rather than working in assembler. It does the 'donkey work' for things like this for you.

Best Wishes