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The IDT79RC4640 is a low-cost member of the Integrated Device

Technology, Inc. RC4000 family, targeted to a variety of performance-

hungry embedded applications. The RC4640 continues the RC4000

tradition of high-performance through high-speed pipelines, high-band-

width caches and bus interface, 64-bit architecture, and careful attention

to efficient control. The cost of this performance is reduced by removing

functional units frequently not required for many embedded applications.

The RC4640 supports a wide variety of embedded processor-based

applications, such as internetworking equipment (routers, switches),

office automation equipment (printers, scanners), and consumer multi-

media game systems. Also, being upwardly software-compatible with

the RC32300 family as well as bus- and upwardly software-compatible

with the IDT RC4000 family, the RC4640 will serve in many of the same

applications. And, the RC4640 supports applications that require integer

digital signal processing (DSP) functions.

The RC64475 and RC64575 processors offer a direct migration path

for designs based on IDT’s RC4650 processors, through full pin and

socket compatibility.

The RC4640 brings 64-bit performance levels to lower cost systems.

High performance is preserved by retaining large on-chip two-way set-

associative caches, a streamlined high-speed pipeline, high bandwidth,

64-bit execution, and facilities such as early restart for data cache

misses.

These techniques allow the system designer over 3.2 GB/sec aggre-

gate internal bandwidth, 500 MB/sec bus bandwidth, almost 352 Dhrys-

tone MIPS, 89MFlops, and 133.5 M Mul-Add/sec. An array of tools

facilitates rapid development of RC4640-based systems, allowing a

wide variety of customers access to the processor’s high-performance

capabilities while maintaining short time-to-market goals.

Some key elements of the RC4640 are briefly described below. More

detailed information is available in the IDT79RC4640/IDT79RC4650

RISC Processor Hardware User’s Manual.

The RC4640 uses a 5-stage pipeline that is similar to the

IDT79RC3000 and the IDT79RC4700 processors. The simplicity of this

pipeline allows the RC4640 to cost less than super-scalar processors

and require less power than super-pipelined processors. So, unlike

superscalar processors, applications that have large data dependen-

cies, or require frequent load/stores, can still achieve peak performance.