B- 2 M68040 USER’S MANUAL MOTOROLA
INSTRUCTION
FETCH
DECODE
EFFECTIVE
ADDRESS
CALCULATE
EXECUTE
EFFECTIVE
ADDRESS
FETCH
INSTRUCTION
CACHE/ACCESS/SNOOP
CONTROLLER
BUS
CONTROL
SIGNALS
DATA
BUS
ADDRESS
BUS
DATA
CACHE/ACCESS/SNOOP
CONTROLLER
OPERAND DATA BUS
INSTRUCTION DATA BUS
INSTRUCTION
CACHE
DATA
CACHE
DATA ACCESS CONTROL UNIT
INSTRUCTION ACCESS CONTROL UNIT B
U
S
C
O
N
T
R
O
L
L
E
R
INSTRUCTION
ADDRESS
DATA
ADDRESS
WRITE-BACK
INTEGER
UNIT
Figure B-1. MC68EC040 Block Diagram
With the exception of the memory management unit (MMU), the floating-point unit (FPU),
and their respective registers, the MC68EC040 programming model, data formats and
types, instruction set (except all instructions beginning with an “F”, PTEST, and PFLUSH),
and caches are the same as described in Section 1 Introduction for the MC68040.
Figures B-2 and B-3 illustrate the programming model and functional signal groups for the
MC68EC040.
