hashst

Hash Store

hashst RA

Stores the computed doubleword hash value to a doubleword storage location.

Details

The Hash Store instruction computes a doubleword hash value using the contents of two GPRs and a doubleword key provided by an SPR, then stores this value into a doubleword in storage addressed by the effective address (EA).

Pseudocode Operation

DW ←32×DX + D
d ←EXTS(0b111_1111 || DW || 0b000)
EA ←(RA) + d
temp ←HashDigest((RA), (RB), HASHKEYR)
MEM(EA, 8) ←temp

Programming Note

The EA specified by the Hash instructions — (RA) + EXTS(0b111_1111 || DW || 0b000) — can be expressed as (RA) −(64−DW)×8. Therefore the Hash instructions can only access one of the 64 doublewords preceding the address provided by RA.

Example

hashst r4

Encoding

Binary Layout
0
0
D
6
RA
11
RB
16
DX
21
754
26
 
Format X-form
Opcode 0x7C0005E3
Extension Base
Registers Altered HASHKEYR

Operands

  • RA
    Address
  • RB
    Source General Purpose Register
  • offset
    Offset to be added to the base address in RA
  • offset
    Offset to be added to the base address in RB