There are no rotate readily available in Perl, but Perl does have shift operators (<< and >>) and that's all you need:

$D1 = ($num >> 7) & 0x01;  # 1 bit  starting at bit 7.
$D2 = ($num >> 4) & 0x07;  # 3 bits starting at bit 4.
$D3 = ($num >> 0) & 0x0F;  # 4 bits starting at bit 0.

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The above is much easier than using unpack because unpack('b', ...) returns a string representation of the number. You can work around it as follows (for fields no bigger than 8 bits):

@D = map { unpack('C', pack('b*', $_)) } unpack('b1b3b4', 162);

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In reply to Re: Extracting Bit Fields (Again) by ikegami
in thread Extracting Bit Fields (Again) by ozboomer

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