Zbkb Extension

6 instructions and 2 pseudo-instructions in the Zbkb extension.

• brev8 - Reverse bits in bytes
• pack - No synopsis available
• packh - No synopsis available
• packw - No synopsis available
• unzip - Bit deinterleave
• zext.h - Pseudo-Instruction (→ pack)
• zext.h - Pseudo-Instruction (→ packw)
• zip - Bit interleave