Please note: This page only shows the instructions changed or added with the i4040. For the others, see i4004.
| Nib 1 | Nib 2 | Nib 3 | Nib 4 | Mnemonic | Desc |
| 0000 | 0001 | - | - | HLT | Halts the CPU. |
| 0000 | 0010 | - | - | BBS | Return from subroutine and restore memory index. |
| 0000 | 0011 | - | - | LCR | Memory bank status is loaded into Acc. |
| 0000 | 0100 | - | - | OR4 | Perform logical OR on Acc and register 4. |
| 0000 | 0101 | - | - | OR5 | Perform logical OR on Acc and register 5. |
| 0000 | 0110 | - | - | AN6 | Perform logical AND on Acc and register 6. |
| 0000 | 0111 | - | - | AN7 | Perform logical AND on Acc and register 7. |
| 0000 | 1000 | - | - | DB0 | Select ROM bank 0. |
| 0000 | 1001 | - | - | DB1 | Select ROM bank 1. |
| 0000 | 1010 | - | - | SB0 | Select register bank 0. |
| 0000 | 1011 | - | - | SB1 | Select register bank 1. |
| 0000 | 1100 | - | - | EIN | Enable interrupt detection. |
| 0000 | 1101 | - | - | DIN | Disable interrupt detection. |
| 0000 | 1110 | - | - | RPM | Load Acc from 4289-controlled program RAM |
The Intel i4040 made many improvements upon it's predecessor. Via switching register banks, you can now access 24 registers. There are now interrupts, so now you can make more kinds of software, and make them faster.