Re: using pack() to build a 16 bit word

To pack using bitstrings, you have to have bitstrings (strings of 1s and 0s), not decimal numbers. You can get bitstrings from sprintf:

my ($pos, $aw, $stru) = (2, 5, 6);
my $bits = sprintf('%06b%05b%03b%02b', 0, $stru, $aw, $pos);
print "Bits=<$bits>\n";
my $bstr=pack('b16', $bits);
printf "<$bstr> is %d bytes\n", length($bstr);
print "\nUnpack: ", unpack('B*', $bstr), "\n";
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If you use format strings like 'b6 b5 b3 b2', each unit will be padded out to full byte width, rather than being all jammed together.

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Re: Re: using pack() to build a 16 bit word by fizbin (Chaplain) on May 12, 2004 at 12:33 UTC
Note that whitespace in bitstrings is irrelevant, so if it makes your debugging easier to do, you can always insert some spaces in that `sprintf` line. `-- @/=map{[/./g]}qw/.h_nJ Xapou cets krht ele_ r_ra/; map{y/X_/\n /;print}map{pop@$_}@/for@/` [download]	[reply] [d/l] [select]