Tim Peters <[EMAIL PROTECTED]> wrote:
> > And for 32x32 -> 64, can't this simply be replaced by "(uint64_t)i * j",
> > where uint64_t is as in C99? I'd hope that most compilers would
> > manage to turn this into the appropriate 32x32-bit hardware multiply.
>
> 1. That's C99, not C89, and therefo
On Mon, Nov 10, 2008 at 4:26 PM, Nick Craig-Wood <[EMAIL PROTECTED]> wrote:
>
> Looking at the assembler it produces (x86)
>
> mul:
>pushl %ebp
>xorl%edx, %edx
>movl%esp, %ebp
>movl12(%ebp), %eax
>imull 8(%ebp), %eax
>popl%ebp
>
Here's the test code I was using, modeled on the basic operation
that longobject needs: multiply two digits together and extract
high and low digits from the result.
typedef uint32_t digit;
typedef uint64_t twodigits;
#define SHIFT 30
#define MASK (((digit)1 << SHIFT) - 1)
/* multiply a and b,
