I haven't tried to build this yet, ((I think?)I would need to use MPIR on 64-bit), so I haven't seen the full output, but am I missing something with regard to your use of ior rather than xor? 

sub FNV_1_128_gmpn {
    my $s = shift;
    mpn_set_str(my $h, '144066263297769815596495629667062367629', 10, 
+128);
    mpn_set_str(my $p, '309485009821345068724781371', 10, 128);
    for (unpack 'C*', $s) {
        my $h2 = $h;
        mpn_mul($h, $h2, $p);
        mpn_ior_uint($h, $h, $_);
    }
    return $h;
}

sub FNV_1a_128_gmpn {
    my $s = shift;
    mpn_set_str(my $h, '144066263297769815596495629667062367629', 10, 
+128);
    mpn_set_str(my $p, '309485009821345068724781371', 10, 128 );
    for (unpack 'C*', $s) {
        mpn_ior_uint($h, $h, $_);
        my $h2 = $h;
        mpn_mul($h, $h2, $p);
    }
    return $h;
}

[download]
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^19: Module for 128-bit integer math? (updated) by BrowserUk
in thread Module for 128-bit integer math? by BrowserUk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.