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Appendix A CPU Instruction Set
A.3
Number of Execution States
The tables here can be used to calculate the number of states required for instruction execution.
Table A.4 indicates the number of states required for each cycle (instruction fetch, data read/write,
etc.) in instruction execution, and table A.3 indicates the number of cycles of each type occurring
in each instruction. The total number of states required for execution of an instruction can be
calculated from these two tables as follows:
Execution states = I × S
Examples: When instruction is fetched from on-chip ROM, and an on-chip RAM is accessed.
BSET #0, @FF00
From table A.4:
I = L = 2,
J = K = M = N= 0
From table A.3:
S
= 2,
S
= 2
I
L
Number of states required for execution = 2 × 2 + 2 × 2 = 8
When instruction is fetched from on-chip ROM, branch address is read from on-chip ROM, and
on-chip RAM is used for stack area.
JSR @@ 30
From table A.4:
I = 2,
J = K = 1,
From table A.3:
S
= S
= S
= 2
I
J
K
Number of states required for execution = 2 × 2 + 1 × 2 + 1 × 2 = 8
Rev.3.00 Jul. 19, 2007 page 452 of 532
REJ09B0397-0300
+ J × S
+ K × S
I
J
L = M = N = 0
+ L × S
+ M × S
+ N × S
K
L
M
N
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