DESCRIPTION OF INSTRUCTIONS

4. ADD A, Rr (Add register)

 

 

 

7

 

 

 

 

 

 

 

0

 

Instruction code

:

 

0

0

 

1

0

1

r2

r1

r0

Byte 1

Operation

: (A)(A)+(Rr) r=0 thru 7

 

 

 

 

Number of bytes

: 1

 

 

 

 

 

 

 

 

 

 

Number of cycles

: 1

 

 

 

 

 

 

 

 

 

 

Flags

:

 

C

AC

F0

RS1

RS0

OV

F1

P

(PSW)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

: The register r contents are added to the accumulator. The result

 

 

is placed in the accumulator, and the flags are updated.

Example ADD A, R6

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

 

 

 

0

 

 

 

 

 

Instruction code

:

0

0

1 0

 

1 1

1 0

Byte 1

 

 

 

Before execution Accumulator

0

1

0

1

 

 

0

1

0

0

7

 

 

 

 

 

 

 

 

0

Register 6

 

 

 

 

0

1

0

1

 

 

1

1

0

1

7

 

 

 

 

 

 

 

 

0

After execution Accumulator

1 0 1 1 0 0 0 1

7

0

Register 6

 

0 1 0 1 1 1 0 1

70

249

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Sonic Alert msm80154s, msm83c154s, msm85c154hvs user manual ADD A, Rr Add register, 249