You could add the parameters to the dispatch hash:

use strict;
use warnings;

my (%frame_lookup_by) = (
    21 => {
        desc => "S/W Status",
        value => sub {$_[0]*256 + $_[1]},
    },
    33 => {
        desc => "HK Subcom",
        value => sub { $_[1] % 16 } ,         #modulo 16 of w12
    },
    117 => {
        desc => "General Status",
        value => sub {$_[0]*256 + $_[1] },        
    },
    129 => {
        desc => "Sensor Status",
        value => sub {$_[0]*256 + $_[1] },        
    },
    hash_params => [1, 0],
);

print $frame_lookup_by{21}->{value}->(@{$frame_lookup_by{hash_params}}
+);
[download]

Prints:

256
[download]