pto.pset_b16

pto.pset_b16 is part of the Predicate Generation And Algebra instruction set.

Summary

Construct a 16-bit predicate mask from a compile-time pattern token.

Mechanism

pto.pset_b16 sets the predicate register to a static pattern encoded by the pattern token. No runtime data is consumed; the entire result is determined at assembly time.

For a predicate register of width 16 bits:

\[ \mathrm{mask}_i = \begin{cases} 1 & \text{if lane } i \text{ matches pattern} \\ 0 & \text{otherwise} \end{cases} \]

The pattern token fully determines which bits are set.

Syntax

PTO Assembly Form

%mask = pto.pset_b16 "PATTERN" : !pto.mask<b16>

AS Level 1 (SSA)

%mask = pto.pset_b16 "PATTERN" : !pto.mask<b16>

AS Level 2 (DPS)

pto.pset_b16 "PATTERN" outs(%mask : !pto.mask<b16>)

C++ Intrinsic

vector_bool mask = pset_b16(__cce_simd::PAT_VL8);

Inputs

Operand Type Description
"PATTERN" string attribute Compile-time pattern token

Supported Pattern Tokens

Pattern Predicate Width Meaning
PAT_ALL 16 All 16 bits set to 1
PAT_ALLF 16 All 16 bits set to 0
PAT_VL1 … PAT_VL16 16 First N bits set to 1
PAT_H 16 Bits 8–15 set to 1 (high half), bits 0–7 set to 0
PAT_Q 16 Bits 12–15 set to 1 (upper quarter), bits 0–11 set to 0
PAT_M3 16 Modular: repeat 1-1-1-0 pattern (lanes 3, 7, 11, 15 active)
PAT_M4 16 Modular: repeat 1-1-1-1-0-0-0-0 pattern (lanes 0–3, 8–11 active)

Expected Outputs

Result Type Description
%mask !pto.mask<b16> Constructed 16-bit predicate

Side Effects

None.

Constraints

Constraints

  • Pattern token validity: The pattern token MUST be valid for a 16-bit predicate width. Using a PAT_VL* token with N > 16 is illegal.
  • Predicate context: This operation produces a fixed-width predicate. Programs that use it in a wider context MUST use pack/unpack to adapt.

Exceptions

Exceptions

  • Illegal if the pattern token is not valid for the _b16 (16-bit) variant.
  • Illegal if the pattern token is not supported by the target profile.

Target-Profile Restrictions

Target-Profile Restrictions
Aspect CPU Sim A2/A3 A5
All pattern tokens Simulated Supported Supported
16-bit predicate width Supported Supported Supported

Examples

Construct all-active mask

#include <pto/pto-inst.hpp>
using namespace pto;

void set_all_active(RegBuf<predicate_t>& dst) {
    PSET_B16(dst, "PAT_ALL");
}

Construct modular pattern

// Modular 3 pattern: lanes 3, 7, 11, 15 active
%mod3 = pto.pset_b16 "PAT_M3" : !pto.mask<b16>

Construct first-half-active mask

// High half: bits 8–15 active, bits 0–7 inactive
%high = pto.pset_b16 "PAT_H" : !pto.mask<b16>