DESCRIPTION OF INSTRUCTIONS

74.MOVX A, @DPTR

(Move external memory addressed by data pointer to accumulator)

 

 

 

7

 

 

 

 

 

 

 

0

Instruction code

:

 

1

1

1

0

 

0

0

0

0

Operation

: (A)((DPTR))

 

 

 

 

 

 

Number of bytes

: 1

 

 

 

 

 

 

 

 

 

Number of cycles

: 2

 

 

 

 

 

 

 

 

 

Flags

:

 

C

AC

F0

RS1

 

RS0

OV

F1

P

Byte 1

(PSW)

 

 

 

 

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

: External data memory (RAM) contents addressed by the data

 

 

pointer are stored in the accumulator, and the flag is updated.

Example MOVX A, @DPTR

 

 

 

 

 

 

 

 

 

 

 

7

0

 

 

 

 

 

Instruction code

 

 

:

1

1

1

0

 

0

0 0 0

Byte 1

 

 

Before execution

 

 

 

 

 

Accumulator

 

 

 

 

 

 

 

1

1

1

1

 

1

1

1

1

 

 

 

7

 

 

 

 

 

 

 

0

 

 

DPH

DPL

 

 

 

 

 

 

 

 

DPH

After execution Accumulator

1 0 1 1 1 0 1 0

7

0

DPL

 

0 1 0 1 0 1 1 1 1 0 1 0 1 1 1 1

0 1 0 1 0 1 1 1 1 0 1 0 1 1 1 1

15

8

7

 

 

 

 

 

 

 

0

 

 

57AFH

 

 

 

 

 

 

 

 

1

0

1

1

 

1

0

1

0

 

 

7

 

 

 

 

 

 

 

0

15

8

7

 

 

 

 

 

 

 

0

 

 

57AFH

 

 

 

 

 

 

 

 

1

0

1

1

 

1

0

1

0

 

 

7

 

 

 

 

 

 

 

0

333

Page 340
Image 340
Sonic Alert msm80154s, msm83c154s, msm85c154hvs user manual 333, Dpl Dph, 57AFH