This document describes various arithmetic instructions for the MPI (Microprocessor Intel) including ADD, SUB, ADC, SBB, INR, DCR, INX, DCX, and DAD. It provides the opcode, operands, byte size, machine cycles, and T states for each instruction. The instructions perform operations like adding, subtracting, incrementing and decrementing registers and memory values, and adjusting the accumulator from binary to BCD format.

1. SUBJECT : MPI

2. TOPIC ARITHMATIC
INSTRUCTION

3. ADD
opcode operand byte M-cycle T states
ADD R 1 1 4
ADD M 1 2 7
The contents of the register or memory are added to the contents of the accumulator and the result is stored
in the accumulator.
All flags are affected by implementing this instruction.
Example − ADD K.

4. ADI
opcode operand byte M cycle T states
ADI 8 bit data 2 2 7
Add the immediate to the accumulator
The 8-bit data is added to the contents of the accumulator and the result is stored in the accumulator. all flags
are affected.
Example − ADI 55K

5. ADC
opcode operand byte M cycle T states
ADC R 1 1 4
ADC M 1 2 7
Add register to the accumulator with carry
The contents of the register or memory & M the Carry flag are added to the contents of the accumulator and
the result is stored in the accumulator.
ALL flags are affected implementing this instruction
Example − ADC K

6. ACI
opcode operand byte M cycle T states
ACI 8 bit data 2 2 7
Add the immediate to the accumulator with carry
The 8-bit data and the Carry flag are added to the contents of the accumulator and the result is stored in the
accumulator.
Example − ACI 55K

7. SUB
opcode operand byte M cycle T states
SUB R 1 1 4
SUB M 1 2 7
Subtract the register or the memory from the accumulator
The contents of the register or the memory are subtracted from the contents of the accumulator, and the
result is stored in the accumulator. All flags are affected.
A-register or A-M
Example − SUB K

8. SUI
opcode operand byte M cycle T states
SUI 8-bit data 2 2 7
Subtract the immediate from the accumulator
The 8-bit data is subtracted from the contents of the accumulator & the result is stored in the accumulator.
All flags are affected.
Example − SUI 55K

9. SBB
opcode operand byte M cycle T states
SBB R 1 1 4
SBB M 1 2 7
Subtract the source and borrow from the accumulator
The contents of the register or the memory & M the Borrow flag are subtracted from the contents of the
accumulator and the result is placed in the accumulator.
All flags are affected.
Example − SBB K

10. SBI
opcode operand byte M cycle T states
SBI 8 bit data 2 2 7
Subtract the immediate from the accumulator with borrow
This instruction will subtract 8-bit immediate data with borrow and result will be stored in AC. By implementing
this instruction all flags are affected.

11. INR
opcode operand byte M cycle T states
INR R 1 1 4
INR M 1 3 10
Increment the register or the memory by 1
The contents of the designated register or the memory are incremented by 1 and their result is stored at the
same place.no flags are affected.
Example − INR K

12. DCR
opcode operand byte M cycle T states
DCR R 1 1 4
DCR M 1 3 10
Decrement the register or the memory by 1
The contents of the designated register or memory are decremented by 1 and their result is stored at the same
place.no flags are affected.
Example − DCR K

13. INX
opcode operand byte M cycle T states
INX REGISTER PAIR 1 1 6
Increment register pair by 1
The contents of the designated register pair are incremented by 1 and their result is stored at the same place.
No flags are affected.
Example − INX K

14. DCX
opcode operand byte M cycle T states
DCX REGISTER PAIR 1 1 6
Decrement the register pair by 1
The contents of the designated register pair are decremented by 1 and their result is stored at the same place.
No flags are affected.
Example − DCX K

15. DAD
opcode operand byte M cycle T states
DAD REGISTER PAIR
(HL,DE,BC)
1 3 10
Decimal adjust accumulator
The contents of the accumulator are changed from a binary value to two 4-bit BCD digits.
If the value of the low-order 4-bits in the accumulator is greater than 9 or if AC flag is set, the instruction adds
6 to the low-order four bits.
If the value of the high-order 4-bits in the accumulator is greater than 9 or if the Carry flag is set, the
instruction adds 6 to the high-order four bits.
Example − DAA