pto.tsubs

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

Summary

Elementwise subtract a scalar from a tile.

Mechanism

Elementwise subtract a scalar from a 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:

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

Syntax

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

Synchronous form:

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

AS Level 1 (SSA)

%dst = pto.tsubs %src, %scalar : (!pto.tile<...>, dtype) -> !pto.tile<...>

AS Level 2 (DPS)

pto.tsubs ins(%src, %scalar : !pto.tile_buf<...>, dtype) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

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

template <typename TileDataDst, typename TileDataSrc, typename... WaitEvents>
PTO_INST RecordEvent TSUBS(TileDataDst &dst, TileDataSrc &src0, typename TileDataSrc::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

  • Common constraints:

    • dst and src0 must use the same element type.
    • Scalar type must match TileDataSrc::DType.

  • Valid region:

    • The op uses dst.GetValidRow() / dst.GetValidCol() as the iteration domain.

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):

    • TileData::DType must be one of: int32_t, int, int16_t, half, float16_t, float, float32_t.
    • Tile location must be vector (TileData::Loc == TileType::Vec).
    • Runtime: src0.GetValidRow() == dst.GetValidRow() and src0.GetValidCol() == dst.GetValidCol().

  • Implementation checks (A5):

    • TileData::DType must be one of: int32_t, int, int16_t, half, float16_t, float, float32_t.
    • Tile location must be vector (TileDataDst::Loc == TileType::Vec and TileDataSrc::Loc == TileType::Vec).
    • Static valid bounds: TileDataDst::ValidRow <= TileDataDst::Rows, TileDataDst::ValidCol <= TileDataDst::Cols, TileDataSrc::ValidRow <= TileDataSrc::Rows, and TileDataSrc::ValidCol <= TileDataSrc::Cols.
    • Runtime: src0.GetValidRow() == dst.GetValidRow() and src0.GetValidCol() == dst.GetValidCol().

Examples

#include <pto/pto-inst.hpp>

using namespace pto;

void example() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  TileT x, out;
  TSUBS(out, x, 1.0f);
}

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.tsubs %src, %scalar : (!pto.tile<...>, 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.tsubs %src, %scalar : (!pto.tile<...>, dtype) -> !pto.tile<...>

PTO Assembly Form

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