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M68020 USER’S MANUAL
MOTOROLA
8.2.16 Control Instructions
The control instructions table indicates the number of clock periods needed for the
processor to perform the specified operation. Footnotes specify when it is necessary to
add an entry from another table to calculate the total effective execution time for the given
instruction. 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.
Instruction
Best Case
Cache Case
Worst Case
ANDI to SR
9(0/0/0)
12(0/0/0)
15(0/2/0)
EORI to SR
9(0/0/0)
12(0/0/0)
15(0/2/0)
ORI to SR
9(0/0/0)
12(0/0/0)
15(0/2/0)
ANDI to CCR
9(0/0/0)
12(0/0/0)
15(0/2/0)
EORI to CCR
9(0/0/0)
12(0/0/0)
15(0/2/0)
ORI to CCR
9(0/0/0)
12(0/0/0)
15(0/2/0)
BSR
5(0/0/1)
7(0/0/1)
13(0/2/1)
**
CALLM (Type 0)
28(2/0/6)
30(2/0/6)
36(2/2/6)
**
CALLM (Type 1)—No Stack Copy
48(5/0/8)
50(5/0/8)
56(5/2/8)
**
CALLM (Type 1)—No Stack Copy
55(6/0/8)
57(6/0/8)
64(6/2/8)
**
CALLM (Type 1)—Stack Copy
63 + 6n (7 + n/0/8 + n)
65 + 6n (7 + n/0/8 + n)
71 + 6n (7 + n/2/8 + n)
CAS (Successful Compare)
15(1/0/1)
16(1/1/1)
CAS (Unsuccessful Compare)
12(1/0/0)
13(1/1/0)
CAS2 (Successful Compare)
23(2/0/2)
25(2/0/2)
28(2/2/2)
CAS2 (Unsuccessful Compare)
19(2/0/0)
22(2/0/0)
25(2/2/0)
*
CHK
8(0/0/0)
8(0/1/0)
**
CHK2 EA,Rn
16(2/0/0)
18(2/0/0)
18(2/1/0)
%
JMP
1(0/0/0)
4(0/0/0)
7(0/2/0)
%
JSR
3(0/0/1)
5(0/0/1)
11(0/2/1)
LEA
2(0/0/0)
3(0/1/0)
LINK.W
3(0/0/1)
5(0/0/1)
7(0/1/1)
LINK.L
4(0/0/1)
6(0/0/1)
10(0/2/1)
NOP
2(0/0/0)
3(0/1/0)
PEA
3(0/0/1)
5(0/0/1)
6(0/1/1)
RTD
9(1/0/0)
10(1/0/0)
12(1/2/0)
RTM (Type 0)
18(4/0/0)
19(4/0/0)
22(4/2/0)
RTM (Type 1)
31(6/0/1)
32(6/0/1)
35(6/2/1)
RTR
13(2/0/0)
14(2/0/0)
15(2/2/0)
RTS
9(1/0/0)
10(1/0/0)
12(1/2/0)
UNLK
5(1/0/0)
6(1/0/0)
7(1/1/0)
n—Number of Operand Transfers Required
%—Add Jump Effective Address Time
*Add Fetch Effective Address Time
** Add Fetch Immediate Address Time
Add Calculate Effective Address Time
Add Calculate Immediate Address Time
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