Motorola MC68030 User Manual page 389

SECTION 10
COPROCESSOR INTERFACE DESCRIPTION
The M68000 Family of general-purpose microprocessors provides a level of
performance that satisfies a wide range of computer applications. Special-
purpose hardware, however, can often provide a higher level of performance
for a specific application. The coprocessor concept allows the capabilities
and performance of a general-purpose processor to be enhanced for a par-
ticular application without encumbering the main processor architecture. A
coprocessor can efficiently meet specific capability requirements that must
typically be implemented in software by a general-purpose processor. With
a general-purpose main processor and the appropriate coprocessor(s), the
processing capabilities of a system can be tailored to a specific application.
The MC68030 supports the M68000 coprocessor interface described in this
section. The section is intended for designers who are implementing copro-
cessors to interface with the MC68030.
The designer of a system that uses one or more Motorola coprocessors (the
MC68881 or MC68882 floating-point coprocessor, for example) does not re-
quire a detailed knowledge of the M68000 coprocessor interface. Motorola
coprocessors conform to the interface described in this section. Typically,
they implement a subset of the interface, and that subset is described in the
coprocessor user's manual. These coprocessors execute Motorola defined
instructions that are described in the user's manual for each c'oprocessor.
10.1 INTRODUCTION
The distinction between standard peripheral hardware and a M68000 copro-
cessor is important from a perspective of the programming model. The pro-
gramming model of the main processor consists of the instruction set, register
set, and memory map available to the programmer. An M68000 coprocessor
is a device or set of devices that communicates with the main processor
through the protocol defined as the M68000 coprocessor interface. The pro-
gramming model for a coprocessor is different than that for a peripheral
device. A coprocessor adds additional instructions and generally additional
registers and data types to the programming model that are not directly
supported by the main processor architecture. The additional instructions
MOTOROLA
MC68030 USER'S MANUAL
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