News & Views / November 1992

New RISC Chip to Emulate 486 and 68040

Tom R. Halfhill

International Meta Systems (Torrance, CA) claims it has a new RISC microprocessor that can emulate an Intel 486 or Motorola 68040 at their full native speeds and at a fraction of their cost. IMS is pitching the CPU for pen computers that need high performance for tasks such as handwriting recognition. It also says the chip could be used in a "chameleon computer" that runs PC and Mac software.

The IMS 3250, slated for mid-1993 production, is a two-chip set with a RISC CPU and an I/O controller. IMS says the 3250 will use 0.7- or 0.8-micron CMOS technol-ogy with the equivalent of 400,000 transistors. Clocked at 100 MHz, the CPU reportedly runs at 90 MIPS in native RISC mode.

What sets the 3250 apart from other RISC chips is its programmable micro-code. Although many CISC processors implement their instruction sets in microcode, most RISC chips do not. Systems designers can reprogram the 3250's microcode using assembler-like tools. IMS says it has written modules that emulate a 486 at 25 MHz and a 68040 at 30 MHz, including FPU support.

To build a computer that runs both PC and Mac applications, a designer would still have to add the appropriate system software. PC clones are easy to make, but a Mac clone would require either licensed Mac ROM chips or their legal equivalent. One possibility is a Mac "compatibility engine" such as the toolbox emulator from Quorum. IMS says the 3250 will cost just $50 to $60 in production quantities.

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