Zcb Extension

Versions

1.0.0
State

ratified

Ratification date

2023-04

Synopsis

Zcb has simple code-size saving instructions which are easy to implement on all CPUs. All proposed encodings are currently reserved for all architectures, and have no conflicts with any existing extensions.

The Zcb extension depends on the Zca extension.

As shown on the individual instruction pages, many of the instructions in Zcb depend upon another extension being implemented. For example, c.mul is only implemented if M or Zmmul is implemented, and c.sext.b is only implemented if Zbb is implemented.

Instructions

The following instructions are defined by this extension:

c.lbu

Load unsigned byte, 16-bit encoding

c.lh

Load signed halfword, 16-bit encoding

c.lhu

Load unsigned halfword, 16-bit encoding

c.not

Bitwise not, 16-bit encoding

c.sb

Store unsigned byte, 16-bit encoding

c.sh

Store unsigned halfword, 16-bit encoding