gc80c520a CORERIVER Semiconductor, gc80c520a Datasheet - Page 92

• Manufacturer Part Number: gc80c520a
• Description: Midas1.0 Family Mask Rom/eprom/romless 8-bit Turbo Microcontrollers
• Manufacturer: CORERIVER Semiconductor

ADD
ADD A, Rn
ADD A, direct
A, <src-byte>
Description:
Operation:
Operation:
Encoding:
Encoding:
Function:
Example:
Cycles:
Cycles:
Bytes:
Bytes:
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 from 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 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 0C3h (11000011b) and register 0 holds 0AAh
(10101010b). The instruction,
ADD A, R0
will leave 6Dh (01101101b) in the Accumulator with the AC flag cleared and
both the carry flag and OV set to 1.
1
1
ADD
(A)
2
2
ADD
(A)
Preliminary
0
0
←
←
0
0
(A) + (Rn)
(A) + (direct)
1
1
0
0
1
0 1 0 1
Page 92 of 187
r
r
r
direct address
Instruction Set