hashchkp

Hash Check Privileged

hashchkp RA

Checks the hash value of a memory location against a computed hash.

Encoding

Binary Layout

0

D

RA

RB

DX

111_1111

DW

0b000

 

Format X-form

Opcode 0x7C000564

Extension Privileged

Operands

• RA
  Address
• RB
  Source General Purpose Register
• offset
  Offset to be added to the contents of RA to form the effective address EA.

Example

hashchkp r4

Registers Altered

HASHPKEYR

Related

More in Privileged

Reference

View in PowerISA v3.1C Specification ↗ OPF Power ISA v3.1C

Description

The HashDigest function is used to compute a hash value from the contents of RA, RB, and the hypervisor privileged SPR HASHPKEYR. This instruction compares the computed hash with the doubleword in storage addressed by EA. If they are unequal, a system trap handler is invoked.

Operation

DW <- 32 * DX + D
d <- EXTS(0b111_1111 || DW || 0b000)
EA <- (RA) + d
temp <- HashDigest((RA), (RB), (HASHPKEYR))
temp1 <- MEM(EA, 8)
if (temp != temp1) then TRAP

Programming Note

See the Programming Notes that appear in the description of hashst and hashchk in Section 3.3.17.2 of Book I.