pto.texpands

pto.texpands is part of the Tile Scalar And Immediate instruction set.

Summary

Broadcast a scalar into a destination tile.

Mechanism

Broadcast a scalar into a destination tile. It operates on tile payloads rather than scalar control state, and its legality is constrained by tile shape, layout, valid-region, and target-profile support.

For each element (i, j) in the valid region:

\[ \mathrm{dst}_{i,j} = \mathrm{scalar} \]

Syntax

Textual spelling is defined by the PTO ISA syntax-and-operands pages.

Synchronous form:

%dst = texpands %scalar : f32, !pto.tile<...>

AS Level 1 (SSA)

%dst = pto.texpands %scalar : dtype -> !pto.tile<...>

AS Level 2 (DPS)

pto.texpands ins(%scalar : dtype) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

Declared in include/pto/common/pto_instr.hpp:

template <typename TileData, typename... WaitEvents>
PTO_INST RecordEvent TEXPANDS(TileData &dst, typename TileData::DType scalar, WaitEvents &... events);

Inputs

  • src is the source tile.
  • scalar is the scalar value broadcast to all lanes.
  • dst names the destination tile.
  • The operation iterates over dst's valid region.

Expected Outputs

dst carries the result tile or updated tile payload produced by the operation.

Side Effects

No architectural side effects beyond producing the destination tile. Does not implicitly fence unrelated traffic.

Constraints

Constraints

  • Valid region:
    • For TileType::Vec :
    • The op fills dst over dst.GetValidRow() / dst.GetValidCol().
    • For TileType::Mat :
    • For Tile : The op fills dst over TileData::Rows / TileData::Cols.
    • For ConvTile : The op fills dst over ConvTileData's shape.

Exceptions

Exceptions

  • Illegal operand tuples, unsupported types, invalid layout combinations, or unsupported target-profile modes are rejected by the verifier or by the selected backend instruction set.
  • Programs must not rely on behavior outside the documented legal domain of this operation, even if one backend currently accepts it.

Target-Profile Restrictions

Target-Profile Restrictions

  • Implementation checks (A2A3):

    • For TileType::Vec :
    • TileData::DType must be one of: uint8_t, int8_t, uint16_t, int16_t, uint32_t, int32_t, half, bfloat16_t, float.
    • Static valid bounds: TileData::ValidRow <= TileData::Rows and TileData::ValidCol <= TileData::Cols.
    • For TileType::Mat :
    • TileData::DType must be one of: uint8_t, int8_t, uint16_t, int16_t, uint32_t, int32_t, half, bfloat16_t, float.
    • Static valid bounds: The range of TileData::Rows * TileData::Cols * sizeof(T) / 32 is [1, 32767].

  • Implementation checks (A5):

    • For TileType::Vec :
    • TileData::DType must be one of: uint8_t, int8_t, uint16_t, int16_t, uint32_t, int32_t, half, float.
    • Tile layout must be row-major (TileData::isRowMajor).
    • Static valid bounds: TileData::ValidRow <= TileData::Rows and TileData::ValidCol <= TileData::Cols.
    • For TileType::Mat :
    • TileData::DType must be one of: uint8_t, int8_t, uint16_t, int16_t, uint32_t, int32_t, half, float.
    • ForTileDataDst::layout == pto::Layout::NC1HWC0 || TileDataDst::layout == pto::Layout::FRACTAL_Z:
      • The range of convtile's (shape0 * shape1 * shape2 * shape3) is [1, 32767].
    • ForTileDataDst::layout == pto::Layout::NDC1HWC0 || TileDataDst::layout == pto::Layout::FRACTAL_Z_3D:
      • The range of convtile's (shape0 * shape1 * shape2 * shape3 * shape4) is [1, 32767].

Examples

Auto

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  TileT dst;
  TEXPANDS(dst, 0.0f);
}

Manual

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  TileT dst;
  TASSIGN(dst, 0x1000);
  TEXPANDS(dst, 0.0f);
}

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.texpands %scalar : dtype -> !pto.tile<...>

Manual Mode

# Manual mode: bind resources explicitly before issuing the instruction.
# Optional for tile operands:
# pto.tassign %arg0, @tile(0x1000)
# pto.tassign %arg1, @tile(0x2000)
%dst = pto.texpands %scalar : dtype -> !pto.tile<...>

PTO Assembly Form

%dst = texpands %scalar : f32, !pto.tile<...>
# AS Level 2 (DPS)
pto.texpands ins(%scalar : dtype) outs(%dst : !pto.tile_buf<...>)