If you're talking about signed int in the form (1 sign bit + 8 bits
absolute value), this is rather easy.

For positive values (MSB = 0), both are equal (assuming that a sign bit = 0
means "positive"). For negative values, you just have to use the rules for
2th complement to complement the remaining 8 bit (bitwise inverting, then
incrementing).

Note that the two representations do not cover the same range: 2th
complement goes from -256 to +255, signed int goes from -255 to +255 (with
two representations for 0). Trying to convert -256 will result in -0, which
is wrong.


But if you're talking about the C language definition of "signed int", it
IS 2th complement...  ;)  just that it is probably 16 bits. You just have
to fill the whole MSByte with the content of the MSbit.

ge

At 09:22 12/03/2001 +0200, Vasile Surducan wrote:
>ooops, with corrected topic again:
> >
> > Dear friends,
> >
> > I need to transform a 9bit, 2'th complement number into a signed integer.
> > This belongs to a equation designed to improve the resolution of a DS1620
> > from 0.5C to 0.1C
> > I'm familiar with 2'th complement but I do not know nothing about signed
> > integers. If anyone can point me to some links or show me some tips I'll
> > be delighted. Please remeber I probably haven't acces to any of the
> > books you may consider.

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