PTRUE (predicate) Initialise predicate from named constraint Set elements of the destination predicate to true if the element number satisfies the named predicate constraint, or to false otherwise. If the constraint specifies more elements than are available at the current vector length then all elements of the destination predicate are set to false. The named predicate constraint limits the number of active elements in a single predicate to: A fixed number (VL1 to VL256) The largest power of two (POW2) The largest multiple of three or four (MUL3 or MUL4) All available, implicitly a multiple of two (ALL). Unspecified or out of range constraint encodings generate an empty predicate or zero element count rather than Undefined Instruction exception. Does not set the condition flags. Green False True 0 0 1 0 0 1 0 1 0 1 1 0 0 0 1 1 1 0 0 0 0 PTRUE <Pd>.<T>{, <pattern>} if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer d = UInt(Pd); constant boolean setflags = FALSE; constant bits(5) pat = pattern; <Pd> Is the name of the destination scalable predicate register, encoded in the "Pd" field. <T> Is the size specifier, size <T> 00 B 01 H 10 S 11 D <pattern> Is the optional pattern specifier, defaulting to ALL, pattern <pattern> 00000 POW2 00001 VL1 00010 VL2 00011 VL3 00100 VL4 00101 VL5 00110 VL6 00111 VL7 01000 VL8 01001 VL16 01010 VL32 01011 VL64 01100 VL128 01101 VL256 0111x #uimm5 101x1 #uimm5 10110 #uimm5 1x0x1 #uimm5 1x010 #uimm5 1xx00 #uimm5 11101 MUL4 11110 MUL3 11111 ALL CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant integer count = DecodePredCount(pat, esize); bits(PL) result; constant integer psize = esize DIV 8; for e = 0 to elements-1 constant bit pbit = if e < count then '1' else '0'; Elem[result, e, psize] = ZeroExtend(pbit, psize); if setflags then PSTATE.<N,Z,C,V> = PredTest(result, result, esize); P[d, PL] = result;