Abstract: A memory management system provides microcode instructions that are divided into multiple tuned phases and stored as separate modules inside a phase code depository. A microcode manager, containing a mode detector, sequence identifier, code loader, drawing data processor and phase executor, interacts with a microcode processor and the phase code depository. The mode detector evaluates a user request for a desired mode. In response to a command from the mode detector, the sequence identifier selects a correct phase sequence that is needed to implement the desired mode. The code loader transfers the phase sequence from the phase code depository to the microcode processor where it is stored in a microcode instruction memory. The memory address for each module within the phase sequence is written to a microcode data memory.