Instruction set summary, See “instruction set summary” on – Rainbow Electronics AT89LP216 User Manual
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3621A–MICRO–6/06
AT89LP216 [Preliminary]
21. Instruction Set Summary
The AT89LP216 is fully binary compatible with the MCS-51 instruction set. The difference
between the AT89LP216 and the standard 8051 is the number of cycles required to execute an
instruction. Instructions in the AT89LP216 may take 1, 2, 3 or 4 clock cycles to complete. The
execution times of most instructions may be computed using
Table 21-1.
Instruction Execution Times and Exceptions
Generic Instruction Types
Cycle Count Formula
Most arithmetic, logical, bit and transfer instructions
# bytes
Branches and Calls
# bytes + 1
Single Byte Indirect (i.e. ADD A, @Ri, etc.)
2
RET, RETI
4
MOVC
3
MOVX
4
MUL
2
DIV
4
INC DPTR
2
Arithmetic
Bytes
Clock Cycles
Hex Code
8051
AT89LP
ADD A, Rn
1
12
1
28-2F
ADD A, direct
2
12
2
25
ADD A, @Ri
1
12
2
26-27
ADD A, #data
2
12
2
24
ADDC A, Rn
1
12
1
38-3F
ADDC A, direct
2
12
2
35
ADDC A, @Ri
1
12
2
36-37
ADDC A, #data
2
12
2
34
SUBB A, Rn
1
12
1
98-9F
SUBB A, direct
2
12
2
95
SUBB A, @Ri
1
12
2
96-97
SUBB A, #data
2
12
2
94
INC Rn
1
12
1
08-0F
INC direct
2
12
2
05
INC @Ri
1
12
2
06-07
INC A
2
12
2
04
DEC Rn
1
12
1
18-1F
DEC direct
2
12
2
15
DEC @Ri
1
12
2
16-17
DEC A
2
12
2
14