MGATHER¶

Tile Operation Diagram¶

MGATHER tile operation

Introduction¶

Gather-load elements from global memory into a tile using per-element indices.

Math Interpretation¶

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

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

Assembly Syntax¶

PTO-AS form: see PTO-AS Specification.

Synchronous form:

%dst = mgather %mem, %idx : !pto.memref<...>, !pto.tile<...> -> !pto.tile<...>

IR Level 1 (SSA)¶

%dst = pto.mgather %mem, %idx : (!pto.partition_tensor_view<MxNxdtype>, pto.tile<...>)
-> !pto.tile<loc, dtype, rows, cols, blayout, slayout, fractal, pad>

IR Level 2 (DPS)¶

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

C++ Intrinsic¶

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

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

Constraints¶

Index interpretation is target-defined. The CPU simulator treats indices as linear element indices into src.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.
%dst = pto.mgather %mem, %idx : (!pto.partition_tensor_view<MxNxdtype>, 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.mgather %mem, %idx : (!pto.partition_tensor_view<MxNxdtype>, pto.tile<...>)

PTO Assembly Form¶

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