ShiftCommand16

ShiftCommand16 is a term used in software libraries and firmware to describe a 16-bit bitwise shift operation used when encoding or preparing a 16-bit command word. It is commonly realized as a function, macro, or inline routine that shifts a 16-bit value by a given number of positions, optionally in a specified direction, and returns a 16-bit result. In many implementations the function takes the input word, the shift amount (0–15), and the direction (left or right). The result is usually masked to 16 bits to prevent overflow from affecting higher bits.

Common forms include a C-style function such as unsigned short ShiftCommand16(unsigned short cmd, unsigned int amount, int direction); or a macro such as #define ShiftCommand16(cmd, amount) ((unsigned short)( (cmd) << (amount) ) & 0xFFFF). Some variants assume unsigned values and perform no sign extension.

Example: shifting left by 4 on 0x1234 yields 0x2340, while shifting right by 4 yields 0x0123. These results illustrate how ShiftCommand16 aligns or isolates specific bit fields within a 16-bit command word, depending on the protocol or encoding scheme.

Applications and context for ShiftCommand16 include encoding flags and fields in hardware interfaces, communication protocols, and compact messaging formats where each field occupies a defined bit position within a 16-bit word. It is typically used alongside related operations such as ShiftCommand8, ShiftCommand32, and bit-field encoding utilities. Caveats include handling endianness, ensuring unsigned arithmetic, and maintaining results within the 0x0000–0xFFFF range.