| Designer | MIPS Computer Systems |
|---|---|
| Bits | 32-bit |
| Design | RISC |
TheR3000 is a 32-bitRISCmicroprocessorchipset developed byMIPS Computer Systems that implemented theMIPS Iinstruction set architecture (ISA). Introduced in June 1988, it was the second MIPS implementation, succeeding theR2000 as the flagship MIPS microprocessor. It operated at 20, 25 and 33.33 MHz.
The MIPS 1 instruction set is small compared to those of the contemporary80x86 and680x0 architectures, encoding only more commonly used operations and supporting fewaddressing modes. Combined with its fixed instruction length and only three different types of instruction formats, this simplifiedinstruction decoding and processing. It employed a 5-stageinstruction pipeline, enabling execution at a rate approaching one instruction per cycle, unusual for its time.
This MIPS generation supports up to four co-processors. In addition to the CPU core, the R3000 microprocessor includes a Control Processor (CP), which contains aTranslation Lookaside Buffer and aMemory Management Unit.[1] The CP works as acoprocessor. Besides the CP, the R3000 can also support an external R3010 numeric coprocessor,[2] along with two other external coprocessors.
The R3000 CPU does not include level 1cache. Instead, its on-chip cache controller operates external data and instruction caches of up to 256 KB each. It can access both caches during the same clock cycle.
The R3000 found much success and was used by many companies in theirworkstations and servers. Users included:
The R3000 was a further development of theR2000 with minor improvements including largerTLB and a faster bus to the external caches. The R3000 die contained 115,000 transistors and measured about 75,000 squaremils (48 mm2).[7] MIPS was afabless semiconductor company, so the R3000 was fabricated by MIPS partners includingIntegrated Device Technology (IDT),LSI Logic,NEC Corporation,Performance Semiconductor, and others. It was fabricated in a 1.2 μmcomplementary metal–oxide–semiconductor (CMOS) process[1] with two levels ofaluminium interconnect.
The R3000 was also used as an embedded microprocessor. When advances in technology rendered it obsolete for high-performance systems, it found continued use in lower-cost designs. Companies such asLSI Logic andIntegrated Device Technology developed derivatives of the R3000 specifically forembedded systems.
Derivatives of the R3000 for non-embedded applications include:
Derivatives of the R3000 for embedded applications include:
