Motorola MC68020 User Manual

8- 40 M68020 USER’S MANUAL MOTOROLA
8.2.18 Save and Restore Operations
The save and restore operations table indicates the number of clock periods needed for
the processor to perform the specified state save or return from exception, with complete
execution times and stack length given. No additional tables are needed to calculate total
effective execution time for these operations. The total number of clock cycles is outside
the parentheses; the number of read, prefetch, and write cycles is given inside the
parentheses as (r/p/w). These cycles are included in the total clock cycle number.
Operation Best Case Cache Case Worst Case
Bus Cycle Fault (Short) 42(1/0/10) 43(1/0/10) 50(1/2/10)
Bus Cycle Fault (Long) 79(1/0/24) 79(1/0/24) 86(1/2/24)
RTE (Normal) 20(4/0/0) 21(4/0/0) 24(4/2/0)
RTE (Six Word) 20(4/0/0) 21(4/0/0) 24(4/2/0)
RTE (Throwaway)* 15(4/0/0) 16(4/0/0) 39(4/0/0)
RTE (Coprocessor) 31(7/0/0) 32(7/0/0) 33(7/1/0)
RTE (Short Fault) 42(10/0/0) 43(10/0/0) 45(10/2/0)
RTE (Long Fault) 91(24/0/0) 92(24/0/0) 94(24/2/0)
*Add the time for RTE on second stack frame.

Motorola MC68020 Specifications

General

Brand	Motorola
Model	MC68020
Category	Computer Hardware
Language	English