SAB80C517-M16 SIEMENS [Siemens Semiconductor Group], SAB80C517-M16 Datasheet - Page 178

• Manufacturer Part Number: SAB80C517-M16
• Description: 8-Bit CMOS Single-Chip Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

ADD
Function:
Description:
Example:
ADD
Operation:
Encoding:
Bytes:
Cycles:
ADD
Operation:
Encoding:
Bytes:
Cycles:
Semiconductor Group
A, <src-byte>
A,Rn
A,direct
Add
ADD adds the byte variable indicated to the accumulator, leaving the result in the
accumulator. The carry and auxiliary carry flags are set, respectively, if there is a
carry out of bit 7 or bit 3, and cleared otherwise. When adding unsigned integers,
the carry flag indicates an overflow occurred.
OV is set if there is a carry out of bit 6 but not out of bit 7, or a carry out of bit 7 but
not out of bit 6; otherwise OV is cleared. When adding signed integers, OV indicates
a negative number produced as the sum of two positive operands, or a positive sum
from two negative operands.
Four source operand addressing modes are allowed: register, direct, register-
indirect, or immediate.
The accumulator holds 0C3 H (11000011 B ) and register 0 holds 0AA H
(10101010 B ).
The instruction
ADD
will leave 6D H (01101101 B ) in the accumulator with the AC flag cleared and both
the carry flag and OV set to 1.
ADD
(A)
1
1
ADD
(A)
2
1
0 0 1 0
0 0 0 1
(A) + (Rn)
(A) + (direct)
A,R0
0 1 0 1
1 r r r
direct address
179
Instruction Set