Intel Embedded Microcontroller Encoding Hex Code Operation, ADD dest,src Function Add, ADD R1,R0

Models: Embedded Microcontroller 8XC251SP 8XC251SA 8XC251SQ 8XC251SB

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INSTRUCTION SET REFERENCE

[Encoding]

Hex Code in:

Operation:

a10 a9 a8 1

0 0 0 1

 

 

Binary Mode = [Encoding] Source Mode = [Encoding]

ACALL

(PC) (PC) + 2 (SP) (SP) + 1 ((SP)) (PC.7:0) (SP) (SP) + 1 ((SP)) (PC.15:8) (PC.10:0) page address

a7 a6 a5 a4

a3 a2 a1 a0

ADD <dest>,<src>

Function: Add

Description: Adds the source operand to the destination operand, which can be a register or the accumu- lator, leaving the result in the register or accumulator. If there is a carry out of bit 7 (CY), the CY flag is set. If byte variables are added, and if there is a carry out of bit 3 (AC), the AC flag is set. For addition of unsigned integers, the CY flag indicates that an overflow occurred.

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, the OV flag is set. When adding signed integers, the OV flag indicates a negative number produced as the sum of two positive operands, or a positive sum from two negative operands.

Bit 6 and bit 7 in this description refer to the most significant byte of the operand (8, 16, or 32 bit).

Four source operand addressing modes are allowed: register, direct, register-indirect, and immediate.

Flags:

 

CY

 

AC

 

OV

N

Z

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Example:

 

 

 

 

 

 

Register 1 contains 0C3H (11000011B) and register 0 contains 0AAH (10101010B). After

 

executing the instruction

 

 

 

 

 

ADD R1,R0

 

 

 

 

 

 

 

register 1 contains 6DH (01101101B), the AC flag is clear, and the CY and OV flags are set.

Variations

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ADD A,#data

 

 

 

 

 

 

 

 

 

Binary Mode

Source Mode

 

 

 

 

Bytes:

2

 

2

 

 

 

 

 

States:

1

 

1

 

 

 

 

 

[Encoding]

0 0 1 0

0 1 0 0

immed. data

A-27

Page 279
Image 279
Intel Embedded Microcontroller Encoding Hex Code Operation, ADD dest,src Function Add, ADD R1,R0, Bytes States Encoding