pto.tsort32

pto.tsort32 is part of the Irregular And Complex instruction set.

Summary

Sort a fixed-size 32-element block and produce an index mapping.

Mechanism

Sort each 32-element block of src together with the corresponding indices from idx, and write the sorted value-index pairs into dst. It belongs to the tile instructions and carries architecture-visible behavior that is not reducible to a plain elementwise compute pattern.

For each row, TSORT32 processes src in independent 32-element blocks. Let block b cover columns 32b ... 32b+31, and let n_b = min(32, C - 32b) be the valid element count of that block.

For each valid element in the block, form a pair

\[ (v_k, i_k) = (\mathrm{src}_{r,32b+k}, \mathrm{idx}_{r,32b+k}), \quad 0 \le k < n_b \]

Then sort the pairs by value and write the sorted value-index pairs to dst. The exact packing layout in dst is target-defined, but semantically the output of each block is the reordered sequence

\[ [(v_{\pi(0)}, i_{\pi(0)}), (v_{\pi(1)}, i_{\pi(1)}), \ldots, (v_{\pi(n_b-1)}, i_{\pi(n_b-1)})] \]

where π is the permutation produced by the implementation for that 32-element block.

Notes:

  • idx is an input tile, not an output tile.
  • dst stores sorted value-index pairs, not just sorted values.
  • The CPU simulation sorts in descending order by value, and for equal values keeps smaller indices first.

Syntax

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

Synchronous form:

%dst = tsort32 %src, %idx : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

AS Level 1 (SSA)

%dst = pto.tsort32 %src, %idx : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

AS Level 2 (DPS)

pto.tsort32 ins(%src, %idx : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

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

template <typename DstTileData, typename SrcTileData, typename IdxTileData>
PTO_INST RecordEvent TSORT32(DstTileData &dst, SrcTileData &src, IdxTileData &idx);

template <typename DstTileData, typename SrcTileData, typename IdxTileData, typename TmpTileData>
PTO_INST RecordEvent TSORT32(DstTileData &dst, SrcTileData &src, IdxTileData &idx, TmpTileData &tmp);

Inputs

  • src is the source tile containing values to sort.
  • idx is the index tile providing initial indices.
  • tmp (optional): temporary tile for non-32-aligned tails.
  • dst names the destination tile. The operation iterates over dst's valid region.

Expected Outputs

dst holds sorted value-index pairs from src according to idx order.

Side Effects

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

Constraints

Constraints

  • TSORT32 does not take WaitEvents&... and does not call TSYNC(...) internally; synchronize explicitly if needed.

  • idx is a required input operand in both overloads; it provides the indices that are permuted together with src.

  • Valid region:

    • The implementation uses dst.GetValidRow() as the row count.
    • The implementation uses src.GetValidCol() to determine how many elements participate in sorting in each row.
    • Sorting is performed independently per 32-element block; the 4-argument overload additionally supports non-32-aligned tails with tmp.

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/A5):
    • DstTileData::DType must be half or float.
    • SrcTileData::DType must match DstTileData::DType.
    • IdxTileData::DType must be uint32_t.
    • dst/src/idx tile location must be TileType::Vec, and all must be row-major (isRowMajor).

Examples

Auto

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using SrcT = Tile<TileType::Vec, float, 1, 32>;
  using IdxT = Tile<TileType::Vec, uint32_t, 1, 32>;
  using DstT = Tile<TileType::Vec, float, 1, 64>;
  SrcT src;
  IdxT idx;
  DstT dst;
  TSORT32(dst, src, idx);
}

Manual

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using SrcT = Tile<TileType::Vec, float, 1, 32>;
  using IdxT = Tile<TileType::Vec, uint32_t, 1, 32>;
  using DstT = Tile<TileType::Vec, float, 1, 64>;
  SrcT src;
  IdxT idx;
  DstT dst;
  TASSIGN(src, 0x1000);
  TASSIGN(idx, 0x2000);
  TASSIGN(dst, 0x3000);
  TSORT32(dst, src, idx);
}

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.tsort32 %src, %idx : !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)
# pto.tassign %arg2, @tile(0x3000)
%dst = pto.tsort32 %src, %idx : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

PTO Assembly Form

%dst = tsort32 %src, %idx : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>
# AS Level 2 (DPS)
pto.tsort32 ins(%src, %idx : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)