The SIM instruction is followed by a byte that contains information to set or reset specific bits. Which bits are affected by this byte?

The SIM (Set Interrupt Mask) instruction is used in microprocessor architectures to control the enabling or disabling of specific interrupts by manipulating individual bits in a control register. The byte that follows the SIM instruction contains specific bits that correspond to different hardware interrupts.

1. Bit Structure: In this byte, each bit represents a particular interrupt. Typically, the least significant bit (LSB) corresponds to the highest-priority interrupt, while higher bits correspond to interrupts of lower priority.

2. Bit Manipulation:

   • Setting a bit (usually to 1) enables the interrupt associated with that bit.
   • Resetting a bit (set to 0) disables the associated interrupt.

3. Common Usage: For instance, in an 8-bit byte, if bit 0 is set to 1, then the interrupt associated with bit 0 (typically the highest priority) will be enabled. If bit 1 is set to 0, then the interrupt associated with that bit will be disabled.

4. Conclusion: The specific bits that are affected by the SIM instruction and the subsequent byte depend on the system architecture being used, but in general, each bit corresponds to a unique interrupt within the system's interrupt vector table.

In summary, the SIM instruction allows for flexible control over the interrupt handling of a microprocessor by enabling or disabling interrupts through individual bits in a control byte.