
8-Bit Instruction Execution Times
5-4
EC000 CORE PROCESSOR USER’S MANUAL
MOTOROLA
5.4 IMMEDIATE INSTRUCTION EXECUTION TIMES
The numbers of clock periods listed in
Table 5-6 include the times to fetch immediate oper-
ands, perform the operations, store the results, and read the next operation. The total num-
ber of clock periods, the number of read cycles, and the number of write cycles are shown
in the previously described format. The number of clock periods, the number of read cycles,
and the number of write cycles, respectively, must be added to those of the effective address
calculation where indicated by a plus sign (+).
# — Immediate operand
Dn — Data register operand
An — Address register operand
M — Memory operand
Table 5-5. Standard Instruction Execution Times
Instruction
Size
op<ea>, An
op<ea>, Dn
op Dn, <M>
ADD/ADDA
Byte
Word
Long
—
12(2/0)+
10(2/0)+**
8(2/0)+
10(2/0)+**
12(2/1)+
16(2/2)+
24(2/4)+
AND
Byte
Word
Long
—
8(2/0)+
10(2/0)+**
12(2/1)+
16(2/2)+
24(2/4)+
CMP/CMPA
Byte
Word
Long
—
10(2/0)+
8(2/0)+
10(2/0)+
—
DIVS
DIVU
Word
—
162(2/0)+*
144(2/0)+*
—
EOR
Byte
Word
Long
—
8(2/0)+***
8(2/0)+***
12(2/0)+***
12(2/1)+
16(2/2)+
24(2/4)+
MULS
MULU
Word
—
74(2/0)+*
—
OR
Byte
Word
Long
—
8(2/0)+
8(2/0)+
10(2/0)+**
12(2/1)+
16(2/2)+
24(2/4)+
SUB
Byte
Word
Long
12(2/0)+
10(2/0)+**
8(2/0)+
8(2/0)+
10(2/0)+**
12(2/1)+
16(2/2)+
24(2/4)+
+Add effective address calculation time.
*Indicates maximum base value added to word effective address time.
**The base time of 10 clock periods is increased to 12 if the effective address mode is register direct
or immediate (effective address time should also be added).
***Only available effective address mode is data register direct.
MULS, MULU—The multiply algorithm requires 42+2n clocks where n is dened as:
MULS: n = tag the <ea> with a zero as the MSB; n is the resultant number of 10 or 01 patterns in
the 17-bit source; i.e., worst case happens when the source is $5555.
MULU: n = the number of ones in the <ea>
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Freescale Semiconductor, Inc.
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