Re: [PATCH] Re: Bignum performance (was: Shrinking the C core)

[Emanuel Berg]

Gerd Möllmann wrote:

>> Are we talking 1 word = 2 bytes = 16 bits here, s2c? If so,
>> the range of fixnums are -32 768 to 32 767 inclusive, so
>> those are hardly huge numbers.
>
> It's a 64-bit machine, more specifically an M1. i.e. arm64.
> How you get from there to these 16 bits escapes me.

Here [1] it says a word for ARM is 32 bits.

So to store zero in a fixnum word it will look like this

  00000000 00000000 00000000 00000000

If one bit, the MSB, is used as the sign bit, the interval,
inclusive, is

  (list (* -1 (expt 2 (1- 32)))
        (1-   (expt 2 (1- 32))) )

  (-2147483648 2147483647)

Okay, now we are talking some pretty big number alltho I have
seen even bigger ...

[1] https://modexp.wordpress.com/2018/10/30/arm64-assembly/

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