[issue4258] Use 30-bit digits instead of 15-bit digits for Python integers.

[Mark Dickinson]

Mark Dickinson <dicki...@gmail.com> added the comment:

> unsigned long long m(unsigned long long a, unsigned long b)
> {
>        return a*b;
> }

I think that's doing a 32 x 64 -> 64 multiplication;  what's being used is 
more like this:

unsigned long long m(unsigned long a, unsigned long b)
{
    return (unsigned long long)a*b;
}

which gcc -O3 compiles to:

        pushl   %ebp
        movl    %esp, %ebp
        movl    12(%ebp), %eax
        mull    8(%ebp)
        leave
        ret

_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue4258>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe: 
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com