TSCATTER

指令示意图

TSCATTER tile operation

简介

使用逐元素行索引将源 Tile 的行散播到目标 Tile 中。

数学语义

对每个源元素 (i, j), let k = idx[i,j] and write:

\[ \mathrm{dst\_flat}_{k} = \mathrm{src}_{i,j} \]

Here dst_flat denotes the destination tile viewed as a single linear storage sequence. TSCATTER does not interpret idx[i,j] as a destination row selector. On the standard row-major tile layout, this is equivalent to writing the k-th flattened destination element.

If multiple elements map to the same destination location, the final value is implementation-defined (last writer wins in the current implementation).

汇编语法

PTO-AS 形式：参见 PTO-AS Specification.

同步形式：

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

AS Level 1（SSA）

%dst = pto.tscatter %src, %idx : (!pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

AS Level 2（DPS）

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

C++ 内建接口

声明于 include/pto/common/pto_instr.hpp:

template <typename TileDataD, typename TileDataS, typename TileDataI, typename... WaitEvents>
PTO_INST RecordEvent TSCATTER(TileDataD &dst, TileDataS &src, TileDataI &indexes, WaitEvents &... events);

约束

  • 实现检查 (A2A3):
  • TileDataD::Loc, TileDataS::Loc, TileDataI::Loc must be TileType::Vec.
  • TileDataD::DType, TileDataS::DType must be one of: int32_t, int16_t, int8_t, half, float32_t, uint32_t, uint16_t, uint8_t, bfloat16_t.
  • TileDataI::DType must be one of: int16_t, int32_t, uint16_t or uint32_t.
  • indexes values are interpreted as flattened destination element offsets in destination tile storage order.
  • No bounds checks are enforced on indexes values.
  • Static valid bounds: TileDataD::ValidRow <= TileDataD::Rows, TileDataD::ValidCol <= TileDataD::Cols, TileDataS::ValidRow <= TileDataS::Rows, TileDataS::ValidCol <= TileDataS::Cols, TileDataI::ValidRow <= TileDataI::Rows, TileDataI::ValidCol <= TileDataI::Cols.
  • TileDataD::DType and TileDataS::DType must be the same.
  • When size of TileDataD::DType is 4 bytes, the size of TileDataI::DType must be 4 bytes.
  • When size of TileDataD::DType is 2 bytes, the size of TileDataI::DType must be 2 bytes.
  • When size of TileDataD::DType is 1 bytes, the size of TileDataI::DType must be 2 bytes.
  • 实现检查 (A5):
  • TileDataD::Loc, TileDataS::Loc, TileDataI::Loc must be TileType::Vec.
  • TileDataD::DType, TileDataS::DType must be one of: int32_t, int16_t, int8_t, half, float32_t, uint32_t, uint16_t, uint8_t, bfloat16_t.
  • TileDataI::DType must be one of: int16_t, int32_t, uint16_t or uint32_t.
  • indexes values are interpreted as flattened destination element offsets in destination tile storage order.
  • No bounds checks are enforced on indexes values.
  • Static valid bounds: TileDataD::ValidRow <= TileDataD::Rows, TileDataD::ValidCol <= TileDataD::Cols, TileDataS::ValidRow <= TileDataS::Rows, TileDataS::ValidCol <= TileDataS::Cols, TileDataI::ValidRow <= TileDataI::Rows, TileDataI::ValidCol <= TileDataI::Cols.
  • TileDataD::DType and TileDataS::DType must be the same.
  • When size of TileDataD::DType is 4 bytes, the size of TileDataI::DType must be 4 bytes.
  • When size of TileDataD::DType is 2 bytes, the size of TileDataI::DType must be 2 bytes.
  • When size of TileDataD::DType is 1 bytes, the size of TileDataI::DType must be 2 bytes.

示例

自动（Auto）

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  using IdxT = Tile<TileType::Vec, uint16_t, 16, 16>;
  TileT src, dst;
  IdxT idx;
  TSCATTER(dst, src, idx);
}

手动（Manual）

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  using IdxT = Tile<TileType::Vec, uint16_t, 16, 16>;
  TileT src, dst;
  IdxT idx;
  TASSIGN(src, 0x1000);
  TASSIGN(dst, 0x2000);
  TASSIGN(idx, 0x3000);
  TSCATTER(dst, src, idx);
}