The Enable Interrupts (EI) and Disable Interrupts (DI) instructions authorise the microprocessor to allow or reject interrupts. In case of EI, the interrupts will be enabled following the completion of the next instruction following the EI. This allows at least one more instruction like JMP or RET, to be executed before the microprocessor allows itself to be again interrupted. In the DI, the interrupts are disabled immediately and no flags are affected.
The Read Interrupt Mask (RIM) and Set Interrupt Mask (SIM) instructions are used to provide interrupt services of the 8085 microprocessor with the help of the Serial Input Data (SID) and Serial Output Data (SOD) pins on the device. The discussion of the above two instructions are as follows.
Accumulator content for SIM
Accumulator content for RIM instruction