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RDFFR (unpredicated)

Read the first-fault register

Read the first-fault register (FFR) and place in the destination predicate without predication.

This instruction is illegal when executed in Streaming SVE mode, unless FEAT_SME_FA64 is implemented and enabled.

SVE

(FEAT_SVE)

313029282726252423222120191817161514131211109876543210
0010010100011001111100000000Pd
opS

Encoding

RDFFR <Pd>.B

Decode for this encoding

if !IsFeatureImplemented(FEAT_SVE) then EndOfDecode(Decode_UNDEF); constant integer d = UInt(Pd);

Assembler Symbols

<Pd>

Is the name of the destination scalable predicate register, encoded in the "Pd" field.

Operation

CheckNonStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant bits(PL) ffr = FFR[PL]; P[d, PL] = ffr;