Re^3: reproducing javascripts >> operator

[shmem]

The actual problem I'm having is the script below works on a 32 bit perl and does not on a 64 bit perl

At least rshift() fixes the different-output issue; it works

# 32bit:
perl -e 'printf"%vd\n",$^V; do pop' 1120752.pl
5.8.8
98
xxx:eeee:YRM1k2jP:1749307403
# 64bit:
perl -e 'printf"%vd\n",$^V; do pop' 1120752.pl
5.14.2
98
xxx:eeee:YRM1k2jP:1749307403

...for some value of "works". The 98 ostensibly comes from the line

say $t if $i == 0;

...and something else besides that may need to be fixed. Your turn.

[mje]

Thanks, I worked it.

A 64 bit number which when you look at the low 32 bits is positive is shifted 8 bits right differently in 64 bit world to the same 32 bits in 32 bit land i.e., 0xffffffff01111111 in 64 bit land is shifted 8 bits right and shifts ff into the lower 32 bits whereas 0x11111111 shifted right in 32 bit land has 00 shifted into the left.

I managed to keep the original code with use integer and perl's >> by adding

            my $to_shift = $crc;
            if (($crc & 0x80000000) != 0) {
                $to_shift |= 0xffffffff00000000;
            } else {
                $to_shift &= 0x00000000ffffffff;
            }
            $to_shift = $to_shift >> 8;