Prefetch memory (literal)
This instruction signals to the memory system that memory accesses to a location are likely to occur soon. The memory system can respond by taking actions that are expected to speed up the memory access when it does occur, such as making the cache line containing the specified address available at the level of cache specified by the instruction.
The address for memory accesses is calculated from the PC value and an immediate offset.
The <prfop> operand specifies the prefetch hint as follows:
The effect of a PRFM instruction is IMPLEMENTATION DEFINED. For more information, see Prefetch memory.
For information about addressing modes, see Load/Store addressing modes.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 1 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | imm19 | Rt | ||||||||||||||||||||||
| opc | VR | ||||||||||||||||||||||||||||||
let t : integer = UInt(Rt); let offset : bits(64) = SignExtend{}(imm19::'00');
| <imm5> |
Is the prefetch operation encoding as an immediate, in the range 0 to 31, encoded in the "Rt" field. This syntax is only for encodings that are not accessible using <prfop>. |
| <label> |
Is the program label from which the data is to be loaded. Its offset from the address of this instruction, in the range +/-1MB, is encoded as "imm19" times 4. |
let address : bits(64) = PC64() + offset; let supports_ir : boolean = FALSE; Prefetch(address, t[4:0], supports_ir);
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