DESCRIPTION OF INSTRUCTIONS

8. ADD A, Rr (Add carry plus register to accumulator)

 

 

7

 

 

 

 

 

 

 

 

 

0

 

Instruction code

:

0

0

1

1

 

 

1

 

r2

r1

r0

Byte 1

Operation

: (A)(A)+(C)+(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 carry flag is added to the accumulator,and the register r

 

 

contents are added to the result. The result is placed in the

 

 

accumulator, and the flags are updated.

 

 

Example ADDC A, R2

 

 

 

 

 

 

 

 

 

 

 

 

 

Instruction code

:

70

0 0 1 1 1 0 1 0 Byte 1

Before execution Accumulator

0

1

1

0

 

1

0

0

0

70 Register 2

0

1

1

0

 

1

1

1

0

70 Carry flag

1

After execution Accumulator

1

1

0

1

 

 

0

1

1

1

7

 

 

 

 

 

 

 

 

0

Register 2

 

 

 

 

0

1

1

0

 

 

1

1

1

0

70 Carry flag

0

253

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Image 260
Sonic Alert msm85c154hvs, msm83c154s, msm80154s user manual ADD A, Rr Add carry plus register to accumulator, 253