Description
The MC68882 floating-point coprocessor fully implements the IEEE Standard for Binary Floating Point Arithmetic (ANSI-IEEE Standard 754-1985) for use with the Motorola M68000 Family of micro-processors. An upgrade of the MC68881, it is pin and software compatible with an optimized MPU interface providing in excess of 1.5 times the performance of the MC68881. It is implemented using VLSI technology to give systems designers the highest possible functionality in a physically small device.
Intended primarily for use as a coprocessor to the MC68020 or MC68030 32-bit microprocessor unit(MPU], the MC68882 provides a logical extension to the main MPU integer data processing capabilities. This extension is achieved by providing a very high performance floating-point arith-metic unit and a set of floating-point data registers which are analogous to the use of the integer data registers. The MC68882 instruction set is a natural extension of all earlier members of the M68000 Family, and it supports all of the addressing modes of the host MPU. Due to the flexiblebus interface of the M68000 Family, the MC68882 can be used with any of the MPU devices of the M68000 Family and as a peripheral to non-M68000 processors.Features
· Eight general purpose floating-point data registers, each supporting a full 80-bit extended precision real data format (a 64-bit mantissa plus a sign bit, and a 15-bit signed exponent).
· A 67-bit arithmetic unit to allow very fast calculations, with intermediate precision greater than the extended precision format.
· A 67-bit barrel shifter for high-speed shifting operations (for normalizing etc.).
· Special purpose hardware for high-speed conversion of binary real memory operands to and from the internal extended format.
· Reduced coprocessor interface overhead to increase throughput.
· Forty-six instructions, including 35 arithmetic operations.
· Full conformation to the ANSHEEE 754 standard, including all requirements and suggestions.
· Support of functions not defined by the IEEE standard, including a full set of trigonometric and transcendental functions.
· Seven data types: byte, word and long word integers; single, double, and extended precision real numbersand packed binary coded decimal string real numbers.
· Twenty-two constants available in the on-chip ROM, including m,e, and powers of 10.
· Virtual memory/machine operations.
· Efficient mechanisms for procedure calls, context switches, and interupt handling.
· Concurrent instruction execution with the main processor.
· Concurrent instruction execution of multiple floating-point instructions.
· Use with any host processor, on an 8-,16-, or 32-bit data bus.
(Picture: Pinout)
