Chapter 6, Problem 27E

a.

Program Plan Intro

Instruction Specifier:

• The instruction specifier is used to store the binary value of the instruction.
• It instructs the machine regarding which operation has to be performed.
• Every instruction uses instruction specifier.
• The instruction specifier is 8 bits (1 byte) long.
  • The first four or five bits are used to represent the operation code.
  • The last three bits are used to represent the addressing mode.
    • Immediate addressing mode (000)
    • Direct addressing mode (001)

Diagrammatic representation of instruction specifier:

The instruction specifier is depicted as given below:

Explanation of Solution

b.

Direct addressing mode:

• The last three bits of the instruction specifier is used to refer the addressing mode.
  • Immediate addressing mode (000)
  • Direct addressing mode (001)
• In direct addressing mode, the operand contains the address of the data that is to be loaded into the accumulator.
• If the last three bits of the instruction specifier is “001”, then the address of the data will be available in the operand specifier...