MemWrite

MemWrite is a control signal used in a computer processor’s memory subsystem to enable writing data to memory. It is asserted by the control unit during store instructions, such as store word, store byte, or store halfword, to indicate that the data held in the register file should be written to the addressed memory location. MemWrite works in conjunction with the memory interface’s address lines and the memory’s write enable input.

In architectures that support partial-word stores, MemWrite often interacts with byte-enable or write-mask signals that specify which bytes within a memory word are to be updated. This allows, for example, writing only a single byte or two bytes even when the memory is word-addressable. MemWrite is typically the complement of MemRead, which controls reading from memory.

Timing and implementation vary by design. In a simple single-cycle processor, MemWrite may be active during the memory access phase for the duration of that cycle. In a pipelined processor, MemWrite is generated in the appropriate stage (often during or before the memory access stage) and must be coordinated with address stability and potential hazards such as stalls or memory conflicts.

In hardware descriptions and simulations, MemWrite is represented as a boolean input to the memory block, driven by the control unit based on the decoded instruction fields. It is a fundamental part of the memory write path, separate from but related to MemRead and the broader memory interface.