Embedded Systems Design, 2nd Edition

Embedded processors 63

effectively based everything on stacks and queues. Secondly, the

greater number of instructions it needed increased code size

dramatically at a time when memory was both expensive and low

in density. Without the compiler technology and cheap memory,

a RISC system was not very practical and the ideas were effec-

tively put back on the shelf.

The MPC601 was the first PowerPC processor available. It

has three execution units: a branch unit to resolve branch instruc-

tions, an integer unit and a floating point unit.

The floating point unit supports IEEE format. The processor

is superscalar. It can dispatch up to two instructions and ...