pto.trowexpandadd

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

Summary

Row-wise broadcast add: add a per-row scalar vector.

Mechanism

Row-wise broadcast add: add a per-row broadcast operand to each row of src0.

Mode 1 — Scalar per row (ColMajor expanded operand)

TROWEXPANDADD Mode 1 tile operation

Let R = dst.GetValidRow() and C = dst.GetValidCol(). Let s_i be the per-row scalar taken from the expanded operand.

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

\[ \mathrm{dst}_{i,j} = \mathrm{src0}_{i,j} + s_i \]

Mode 2 — 32-byte block per row (RowMajor expanded operand)

TROWEXPANDADD Mode 2 tile operation

Let b_i be the 32-byte block for row i taken from the expanded operand. The block contains 32 / sizeof(T) values and repeats across the row.

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

\[ \mathrm{dst}_{i,j} = \mathrm{src0}_{i,j} + b_i[\,j \bmod (32 / \mathit{sizeof}(T))\,] \]

Syntax

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

Synchronous form:

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

AS Level 1 (SSA)

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

AS Level 2 (DPS)

pto.trowexpandadd 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 TROWEXPANDADD(TileDataDst &dst, TileDataSrc0 &src0, TileDataSrc1 &src1, WaitEvents &... events);

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

Inputs

  • src0 is the first source tile (the tile to be modified).
  • src1 is the second source tile providing per-row scalar values.
  • tmp (optional): temporary tile for intermediate storage.
  • dst names the destination tile. The operation iterates over dst's valid region.

Expected Outputs

dst[i,j] = src0[i,j] + src1[i,0] (row-wise broadcast add of per-row scalar).

Side Effects

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

Constraints

Constraints

  • TileDataDst::DType == TileDataSrc0::DType == TileDataSrc1::DType.

  • TileDataDst::DType, TileDataSrc0::DType, and TileDataSrc1::DType must be one of: half, float, int16, int32 for A2, A3, and A5; uint16, uint32 for A5.

  • TileDataDst must be RowMajor.

  • Exactly one of src0 or src1 must have the same valid shape as dst. That operand is the full-sized operand; the other operand is the expanded row-broadcast operand.

  • The full-sized operand must be RowMajor.

  • Mode 1: the expanded operand is ColMajor, has valid column count 1, and has valid row count equal to dst.GetValidRow().

  • Mode 2: the expanded operand is RowMajor, has valid row count equal to dst.GetValidRow(), and has valid column count 32 / sizeof(T): 16 for 16-bit types and 8 for 32-bit types.

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

Temporary tile

The C++ API provides an overload with an explicit TileDataTmp &tmp. This overload only supports Mode 1 (ColMajor expanded operand, scalar per row).

  • A2A3: The tmp tile is used as a broadcast buffer. The per-row scalar values from the ColMajor expanded operand are broadcast via the vbrcb instruction into the tmp buffer, creating a 32-byte block per row, which is then used as the expanded operand in the binary operation. The vbrcb instruction uses a repeat stride of 8 blocks (256 bytes) between repeat groups, processing 8 rows per repeat. Minimum tmp size calculation:
    • Common parameters: R = dst.GetValidRow(), T = TileDataDst::DType.
    • For R < 256: $$ \text{tmpSize} = \left\lceil\frac{R}{8}\right\rceil \times 256 \text{ bytes} $$
    • For R >= 256, the operation is looped with at most 30 repeats (240 rows) per loop iteration. The tmp buffer is reused across loops, so the per-loop requirement is: $$ \text{tmpSize} = 30 \times 256 = 7680 \text{ bytes} $$
    • A compact shape-independent upper bound for any Mode 1 invocation is 8 KB (8192 bytes).
    • The 3-arg overload without tmp supports both Mode 1 and Mode 2. For Mode 1, it uses an internal 8 KB buffer (TMP_UB_OFFSET). For Mode 2, no broadcast buffer is needed.
  • A5: The tmp tile is accepted and ignored ([[maybe_unused]]). A5 hardware supports row-broadcast natively via the vlds instruction's broadcast modes, so no scratch buffer is required.

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.trowexpandadd 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 RowVecT = Tile<TileType::Vec, float, 16, 1, BLayout::ColMajor>;
  SrcT src0;
  DstT dst;
  RowVecT src1;
  // Row-expand-add: each row of dst = src0.row + src1.row_scalar
  TROWEXPANDADD(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 RowVecT = Tile<TileType::Vec, float, 16, 1, BLayout::ColMajor>;
  SrcT src0;
  DstT dst;
  RowVecT src1;
  TASSIGN(src0, 0x1000);
  TASSIGN(dst, 0x2000);
  TASSIGN(src1, 0x3000);
  // Row-expand-add in manual mode
  TROWEXPANDADD(dst, src0, src1);
}

Auto Mode

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

PTO Assembly Form

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