MC68030 Datasheet, PDF (419/602 Pages) Motorola, Inc – ENHANCED 32-BIT MICROPROCESSOR

Coprocessor Interface Description
(UNABLE TO LOCATE ART)
Figure 10-43. MC68030 Mid-Instruction Stack Frame
The program counter value saved in this stack frame is the operation word address of the
coprocessor instruction during which the primitive is received. The scanPC field contains the
value of the MC68030 scanPC when the primitive is received. If the current instruction does
not evaluate an effective address prior to the exception request primitive, the value of the
effective address field in the stack frame is undefined.
The coprocessor uses this primitive to request exception processing for an exception during
the instruction dialog with the main processor. If the exception handler does not modify the
stack frame, the MC68030 returns from the exception handler and reads the response CIR.
Thus, the main processor attempts to continue executing the suspended instruction by
reading the response CIR and processing the primitive it receives.
MOTOROLA
MC68030 USER’S MANUAL
10-59