pto.tcolexpandsub

pto.tcolexpandsub is part of the Reduce And Expand instruction set.

Summary

Column-wise broadcast subtract: subtract a per-column scalar vector from each column.

Mechanism

Column-wise broadcast subtract: subtract a per-column scalar vector src1 from src0.

Let R = dst.GetValidRow() and C = dst.GetValidCol(). Let s_j be the per-column scalar taken from src1 (one value per column).

For 0 <= i < R and 0 <= j < C:

\[ \mathrm{dst}_{i,j} = \mathrm{src0}_{i,j} - s_j \]

Syntax

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

Synchronous form:

%dst = tcolexpandsub %src0, %src1 : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

AS Level 1 (SSA)

%dst = pto.tcolexpandsub %src0, %src1 : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

AS Level 2 (DPS)

pto.tcolexpandsub ins(%src0, %src1 : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

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

template <typename TileDataDst, typename TileDataSrc0, typename TileDataSrc1, typename... WaitEvents>
PTO_INST RecordEvent TCOLEXPANDSUB(TileDataDst &dst, TileDataSrc0 &src0, TileDataSrc1 &src1, WaitEvents &... events);

Inputs

  • src0 is the first source tile (the tile to be modified).
  • src1 is the second source tile providing per-column scalar values.
  • dst names the destination tile. The operation iterates over dst's valid region.

Expected Outputs

dst[i,j] = src0[i,j] - src1[0,j] (column-wise broadcast subtract of per-column scalar).

Side Effects

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

Constraints

Constraints

  • TileDataDst::DType, TileDataSrc1::DType must be one of: half, float.

  • Tile shape/layout constraint (compile-time): TileDataDst::isRowMajor.

  • src1 is expected to provide one scalar per column (i.e., its valid shape must cover C values).

  • Exact layout/fractal constraints are target-specific; see backend headers under include/pto/npu/*/TColExpand*.hpp.

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

  • pto.tcolexpandsub preserves PTO-visible semantics across CPU simulation, A2/A3-class targets, and A5-class targets, but concrete support subsets may differ by profile.

  • Portable code must rely only on the documented type, layout, shape, and mode combinations that the selected target profile guarantees.

Examples

Auto

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using SrcT = Tile<TileType::Vec, float, 16, 16>;
  using DstT = Tile<TileType::Vec, float, 16, 16>;
  using ColVecT = Tile<TileType::Vec, float, 1, 16, BLayout::RowMajor>;
  SrcT src0;
  DstT dst;
  ColVecT src1;
  // Col-expand-sub: each column of dst = src0.col - src1.col_scalar
  TCOLEXPANDSUB(dst, src0, src1);
}

Manual

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using SrcT = Tile<TileType::Vec, float, 16, 16>;
  using DstT = Tile<TileType::Vec, float, 16, 16>;
  using ColVecT = Tile<TileType::Vec, float, 1, 16, BLayout::RowMajor>;
  SrcT src0;
  DstT dst;
  ColVecT src1;
  TASSIGN(src0, 0x1000);
  TASSIGN(dst, 0x2000);
  TASSIGN(src1, 0x3000);
  // Col-expand-sub in manual mode
  TCOLEXPANDSUB(dst, src0, src1);
}

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.tcolexpandsub %src0, %src1 : !pto.tile<...>, !pto.tile<...> -> !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.tcolexpandsub %src0, %src1 : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

PTO Assembly Form

%dst = tcolexpandsub %src0, %src1 : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>
# AS Level 2 (DPS)
pto.tcolexpandsub ins(%src0, %src1 : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)