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AIX Version 4.3 Assembler Language Reference

rfid (Return from Interrupt Double Word) Instruction


Reinitializes the Machine State Register and continues processing after an interrupt.




Bits 0, 48-55, 57-59, and 62-63 from the Save Restore Register 1 (SRR1) are placed into the corresponding bits of the Machine State Register (MSR). If the new MSR value does not enable any pending exceptions, then the next instruction is fetched under control of the new MSR value. If the SF bit in the MSR is 1, the address found in bits 0-61 of SRR0 (fullword aligned address) becomes the next instruction address. If the SF bit is zero, then bits 32-61 of SRR0, concatenated with zeros to create a word-aligned adderss, are placed in the low-order 32-bits of SRR0. The high-order 32 bits are cleared. If the new MSR value enables one or more pending exceptions, the exception associated with the highest priority pending exception is generated; in this case the value placed into SRR0 by the exception processing mechanism is the address of the instruction that would have been executed next had the exception not occurred.

Other registers altered:


The rfid instruction is privileged and synchronizing.


This instruction is defined only for 64-bit implementations. Using it on a 32-bit implementation causes an illegal instruction type program exception.

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