Integer readFrom: '11111111' readStream base: 2.  ?

Best,
Karl




On Tue, Jun 16, 2020 at 6:36 PM Eric Gade <eric.gade at gmail.com> wrote:

> Hi everyone,
>
> I'm smack in the middle of making some RISC-V tools in Squeak, which means
> I'm dealing with a lot of low-level bit manipulation.
>
> One question I have is how best to deal with two's complement
> representations of integers in Squeak, and how to translate between the
> different (positive v negative) values based on a given set of bits (or a
> byteArray or whatever).
>
> For example, doing the following:
> -1 printStringBase: 2 nDigits: 8. "11111111"
> Gives the expected binary value "11111111"
>
> However (and as we should expect), evaluating the following:
> 2r11111111. "255"
>
> Gives the (again, expected) value 255.
>
> My question is: what is the best way to convert between the complements in
> Squeak? How can I take 255, examine its bits, and get -1 as the response
> (or convert in the reverse)? I'm assuming there are already ways to deal
> with this, I just cannot find them.
>
> Thanks!
>
> --
> Eric
>
>
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