Hi Segher,
Thanks for your response.
Can you confirm then, that despite returning a 64-bit value, the result will
never actually cross the maximal 32-bit value? Can you perhaps point us at
gcc code, so that we can try to ensure that?
Thanks,
Alex.
-----Original Message-----
From: Segher Boessenkool
Sent: Monday, February 12, 2018 5:01 PM
To: Eitan Azriel
Cc: gcc-help@xxxxxxxxxxx ; Alex Lyakas ; hjl.tools@xxxxxxxxx
Subject: Re: Can _mm_crc32_u64() return a value that is bigger than
MAX_UINT32?
Hello,
On Mon, Feb 12, 2018 at 03:24:14PM +0200, Eitan Azriel wrote:
The signature of _mm_crc32_u64() is:
unsigned int64 _mm_crc32_u64 (
unsigned __int64 crc,
unsigned __int64 v
);
Why does it return int64, and not uint32? Shouldn't it return a valid
CRC32
value?
GCC uses int64 because that is what the ABI/API says it should do.
Presumably it uses int64 for output because it does use it for input
and there was the desire to use the same type everywhere.
Segher
