6. Assembly language programming

Question 1

What does an instruction contain?

Answer 1

Opcode (8 bits) and operand (16 bits). Every opcode mnemonic has its own opcode binary, eg. IN - 0001 0000, INC - …, JPN - …., END - 1111 11111

Question 2

What kinds of addressing modes are there?

Answer 2

1. Immediate
2. Direct
3. Indirect
4. Indexed

Question 3

What two opcodes are provided for I/O commands?

Answer 3

1. IN (with no operands)
2. OUT (with no operands)

Question 4

How are assembly language instructions categorized?

Answer 4

1. Data movement
2. Input/Output
3. Jump
4. Compare
5. Arithmetic
6. Shift
7. Logical

Question 5

What 3 main flags are used in status register?

Answer 5

1. Carry flag, identified as C
2. Negative flag, identified as N,
3. Overflow flag, identified as V