MSCATTER¶

Tile Operation Diagram¶

MSCATTER tile operation

Introduction¶

Scatter-store elements from a tile into global memory using per-element indices.

Math Interpretation¶

For each element (i, j) in the source valid region:

\[ \mathrm{mem}[\mathrm{idx}_{i,j}] = \mathrm{src}_{i,j} \]

If multiple elements map to the same destination location, the final value is implementation-defined (CPU simulator: last writer wins in row-major iteration order).

Assembly Syntax¶

PTO-AS form: see PTO-AS Specification.

Synchronous form:

mscatter %src, %mem, %idx : !pto.memref<...>, !pto.tile<...>, !pto.tile<...>

IR Level 1 (SSA)¶

pto.mscatter %src, %idx, %mem : (!pto.tile<...>, !pto.tile<...>, !pto.partition_tensor_view<MxNxdtype>) -> ()

IR Level 2 (DPS)¶

pto.mscatter ins(%src, %idx : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%mem : !pto.partition_tensor_view<MxNxdtype>)

C++ Intrinsic¶

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

template <typename GlobalData, typename TileSrc, typename TileInd, typename... WaitEvents>
PTO_INST RecordEvent MSCATTER(GlobalData& dst, TileSrc& src, TileInd& indexes, WaitEvents&... events);

Constraints¶

Index interpretation is target-defined. The CPU simulator treats indices as linear element indices into dst.data().
No bounds checks are enforced on indexes by the CPU simulator.

Examples¶

See related examples in docs/isa/ and docs/coding/tutorials/.

ASM Form Examples¶

Auto Mode¶

# Auto mode: compiler/runtime-managed placement and scheduling.
pto.mscatter %src, %idx, %mem : (!pto.tile<...>, !pto.tile<...>, !pto.partition_tensor_view<MxNxdtype>) -> ()

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.mscatter %src, %idx, %mem : (!pto.tile<...>, !pto.tile<...>, !pto.partition_tensor_view<MxNxdtype>) -> ()

PTO Assembly Form¶

mscatter %src, %mem, %idx : !pto.memref<...>, !pto.tile<...>, !pto.tile<...>
# IR Level 2 (DPS)
pto.mscatter ins(%src, %idx : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%mem : !pto.partition_tensor_view<MxNxdtype>)