PTRUES
Initialise predicate from named constraint and set the condition flags
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. Sets the First (N), None (Z), !Last (C) condition flags based on the predicate result, and the V flag to zero.
Green
False
True
0
0
1
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
0
PTRUES <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 = TRUE;
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;