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SIM and RIM for Interrupts

Published on Jun 18 2014 // Interrupts 8085


SIM and RIM for interrupts:

  • The 8085 provide additional masking facility for RST 7.5, RST 6.5 and RST 5.5 using SIM instruction.
  • The status of these interrupts can be read by executing RIM instruction.
  • The masking or unmasking of RST 7.5, RST 6.5 and RST 5.5 interrupts can be performed by moving an 8-bit data to accumulator and then executing SIM instruction.
  • The format of the 8-bit data is shown below

  • The status of pending interrupts can be read from accumulator after executing RIM instruction.
  • When RIM instruction is executed an 8-bit data is loaded in accumulator, which can be interpreted as shown in fig.