Translates an effective address into a real address and stores the result in a general-purpose register.
Note: The rac instruction is supported only in the POWER architecture.
POWER | |
---|---|
rac | RT,RA,RB |
rac. | RT,RA,RB |
The rac instruction computes an effective address (EA) from the sum of the contents of general-purpose register (GPR) RA and the contents of GPR RB, and expands the EA into a virtual address.
If RA is not 0 and if RA is not RT, then the rac instruction stores the EA in GPR RA, translates the result into a real address, and stores the real address in GPR RT.
Consider the following when using the rac instruction:
The rac instruction has two syntax forms. Each syntax form has a different effect on Condition Register Field 0.
Syntax Form | Overflow Exception (OE) | Fixed-Point Exception Register | Record Bit (Rc) | Condition Register Field 0 |
rac | None | None | 0 | None |
rac | None | None | 1 | EQ,SO |
The two syntax forms of the rac instruction do not affect the Fixed-Point Exception Register. If the syntax form sets the Record (Rc) bit to 1, the instruction effects the Equal (EQ) and Summary Overflow (SO) bit in Condition Register Field 0.
Note: The hardware may first search the Translation Look-Aside buffer for the address. If this fails, the Page Frame table must be searched. In this case, it is not necessary to load a Translation Look-Aside buffer entry.
The rac instruction instruction is privileged.