Question

For the machine language instructions 6AF82C and D623D0. What is the opcode in binary?

a)What does the instruction do?

b)What is the register -r field in binary?

c)Which register does it specify?

d)Which addressing mode does it specify?

e)What is the operand specifier in hexadecimal.

Answer 1

I hope this is what you want. If you still have any doubt please let me know.

Please refer to the instruction specifier field for all the detail.

Like if r has a 0 value than Accumulator

If r has a 1 value than indexed register X

If aaa =000 immidiate,

Aaa=001 direct

Aaa =010 indirect

Aaa=011 stack relative

Aaa=100 stack relative deferred

Aaa =101 indexed

Aaa = 110 stack indexed

Aaa=111 stack deferred indexed

1. 6AF82C

CONVERT THIS HEXADECIMAL INSTRUCTION INTO BINARY

6=0110

A=1010

F=1111

8=1000

2=0010

C=1100

IN THIS 32 BIT INSTRUCTION, 4 BITS ARE FOR OPCODE, 1 BIT FOR REGISTER, 3 BITS ARE FOR ADDRESSING MODE AND 16 BITS ARE FOR OPRAND SPECIFIER.

0110                  1                             010                                                     1111 1000 0010 1100

OPCODE      REGISTER TYPE(r)      ADDRESSING MODE (aaa)                           OPERAND SPECIFIER

1. This instruction has a op-code 0110 which, adds to register R
2. –r register field in binary has a value 1.
3. The value 1 specifies the index register R.
4. aaa=010 means indirect address
5. operand specifier is   F82C

2. D623D0

D=1101

6=0110

2=0010

3=0011

D=1101

0=0000

IN THIS 32 BIT INSTRUCTION, 4 BITS ARE FOR OPCODE, 1 BIT FOR REGISTER, 3 BITS ARE FOR ADDRESSING MODE AND 16 BITS ARE FOR OPRAND SPECIFIER.

1101                  0                             110                                                                 0010 0011 1101 0000

OPCODE      REGISTER TYPE(r)      ADDRESSING MODE (aaa)                           OPERAND SPECIFIER

1. Opcode is 1101 which, Loads a byte from memory to register R
2. –r register field has binary value 0.
3. Binary value 0 specifies the accumulator, A
4. Aaa=110 which specifies stack indexed address
5. Operand specifier = 23D0