MC68030 Datasheet, PDF (393/602 Pages) Motorola, Inc – ENHANCED 32-BIT MICROPROCESSOR

Coprocessor Interface Description
10.3.10 Instruction Address CIR
When the coprocessor requests the address of the instruction it is currently executing, the
main processor transfers this address to the 32-bit instruction address CIR. Any transfer of
the scanPC is also performed through the instruction address CIR (refer to 10.4.17 Transfer
Status Register and ScanPC Primitive). The offset from the base address of the CIR set
for the instruction address CIR is $18.
10.3.11 Operand Address CIR
When a coprocessor requests an operand address transfer between the main processor
and the coprocessor, the address is transferred through the 32-bit operand address CIR.
The offset from the base address of the CIR set for the operand address CIR is $1C.
10.4 COPROCESSOR RESPONSE PRIMITIVES
The response primitives are primitive instructions that the coprocessor issues to the main
processor during the execution of a coprocessor instruction. The coprocessor uses
response primitives to communicate status information and service requests to the main
processor. In response to an instruction command word written to the command CIR or a
condition selector in the condition CIR, the coprocessor returns a response primitive in the
response CIR. Within the general and conditional instruction categories, individual
instructions are distinguished by the operation of the coprocessor hardware and also by
services specified by coprocessor response primitives provided by the main processor.
Subsequent paragraphs, beginning with 10.4.2 Coprocessor Response Primitive
General Format, consist of detailed descriptions of the M68000 coprocessor response
primitives supported by the MC68030. Any response primitive that the MC68030 does not
recognize causes it to initiate protocol violation exception processing (refer to 10.5.2.1
Protocol Violations). This processing of undefined primitives supports emulation of
extensions to the M68000 coprocessor response primitive set by the protocol violation
exception handler. Exception processing related to the coprocessor interface is discussed
in 10.5 Exceptions.
MOTOROLA
MC68030 USER’S MANUAL
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