Motorola 68882 FPU family

Motorola 68882 (MC68882) is an enhanced version of 68881 Floating Point Unit. The 68882 is pin- and object-code compatible with the 68881, and, like the 68881, it could work with Motorola 68020 and 68030 microprocessors. The architecture of the 68882 FPU is similar to the 68881. The FPU has 8 directly-addressable 80-bit registers. It supports seven data types: 8-bit, 16-bit and 32-bit integers, single, double and extended-precision floating point numbers, and packed decimal strings. The 68882 always converts external operands into internal extended-precision format, and performs all calculations in this format. The MC68882 has the same instruction set as the 68881 co-processor.

The 68882 FPU includes a few features that significantly improve its performance:

  • The 68882 may execute more than one floating-point instruction at the same time.
  • The MC68882 uses faster conversion method of external operands to/from FPU's internal format.

To get maximum performance from the co-processor the programs needs to be re-compiled specifically for the 68882. The 68882 may run re-compiled programs up to two times faster than the 68881 FPU. Performance gain for older applications, i.e. applications compiled for Motorola 68881 co-processor, is usually is not as impressive - the FPU may run these programs up to 15 - 25% faster than the 68881.


Die pictures:
Use the filter below to display floating-point units that have specific feature(s) incorporated:

Production floating-point units

Motorola MC68882RC16 / MC68882RC16A
16 MHz
68-pin ceramic PGA
Revision A
Motorola MC68882FN25 / MC68882FN25A
25 MHz
68-pin plastic LCC
Revision A
Motorola MC68882RC25 / MC68882RC25A
25 MHz
68-pin ceramic PGA
Revision A
Motorola XC68882RC40A
40 MHz
68-pin ceramic PGA
Revision A
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At a glance

Type:
32-bit floating-point unit
Frequency (MHz):
16.7 - 33.3
Sockets:
PGA68
PLCC68