RCWSSWPP, RCWSSWPPA, RCWSSWPPAL, RCWSSWPPL

Read check write software swap quadword in memory

This instruction atomically loads a 128-bit quadword from a memory location, and conditionally stores the value held in a pair of registers back to the same memory location. Storing back to memory is conditional on RCW Checks and RCWS Checks. The value initially loaded from memory is returned in the same pair of registers. If the RCW Checks fail or the RCWS Checks fail, the architecture permits writing the value read from the location to memory. If the write is performed, the read and the write occur atomically such that no other modification of the memory location can take place between the read and the write. This instruction updates the condition flags based on the result of the RCW Checks and RCWS Checks.

• RCWSSWPPA and RCWSSWPPAL load from memory with acquire semantics.
• RCWSSWPPL and RCWSSWPPAL store to memory with release semantics.
• RCWSSWPP has neither acquire nor release semantics.

Integer
(FEAT_D128 && FEAT_THE)

Decode for all variants of this encoding

if !IsFeatureImplemented(FEAT_D128) || !IsFeatureImplemented(FEAT_THE) then EndOfDecode(Decode_UNDEF); end; if Rt == '11111' then EndOfDecode(Decode_UNDEF); end; if Rt2 == '11111' then EndOfDecode(Decode_UNDEF); end; let t : integer{} = UInt(Rt); let t2 : integer{} = UInt(Rt2); let n : integer{} = UInt(Rn); let soft : boolean = TRUE; let acquire : boolean = A == '1'; let release : boolean = R == '1'; let tagchecked : boolean = n != 31; var rt_unknown : boolean = FALSE; if t == t2 then let c : Constraint = ConstrainUnpredictable(Unpredictable_LSE128OVERLAP); assert c IN {Constraint_UNKNOWN, Constraint_UNDEF, Constraint_NOP}; case c of when Constraint_UNKNOWN => rt_unknown = TRUE; // result is UNKNOWN when Constraint_UNDEF => EndOfDecode(Decode_UNDEF); when Constraint_NOP => EndOfDecode(Decode_NOP); end; end;

Assembler Symbols