TTRANS

Tile Operation Diagram

TTRANS tile operation

Introduction

Transpose with an implementation-defined temporary tile.

Math Interpretation

For a 2D tile, over the effective transpose domain:

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

Exact shape/layout and the transpose domain depend on the target (see Constraints).

Assembly Syntax

PTO-AS form: see PTO-AS Specification.

Synchronous form:

%dst = ttrans %src : !pto.tile<...> -> !pto.tile<...>

Lowering may introduce internal scratch tiles; the C++ intrinsic requires an explicit tmp operand.

AS Level 1 (SSA)

%dst = pto.ttrans %src : !pto.tile<...> -> !pto.tile<...>

AS Level 2 (DPS)

pto.ttrans ins(%src : !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

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

template <typename TileDataDst, typename TileDataSrc, typename TileDataTmp, typename... WaitEvents>
PTO_INST RecordEvent TTRANS(TileDataDst &dst, TileDataSrc &src, TileDataTmp &tmp, WaitEvents &... events);

Constraints

  • Implementation checks (A2A3):
    • sizeof(TileDataSrc::DType) == sizeof(TileDataDst::DType).
    • Source layout must be row-major (TileDataSrc::isRowMajor).
    • Element size must be 1, 2, or 4 bytes.
    • Supported element types are restricted per element width:
    • 4 bytes: uint32_t, int32_t, float
    • 2 bytes: uint16_t, int16_t, half, bfloat16_t
    • 1 byte: uint8_t, int8_t
    • The transpose size is taken from src.GetValidRow() / src.GetValidCol().
  • Implementation checks (A5):
    • sizeof(TileDataSrc::DType) == sizeof(TileDataDst::DType).
    • 32-byte alignment constraints are enforced on the major dimension of both input and output (row-major checks Cols * sizeof(T) % 32 == 0, col-major checks Rows * sizeof(T) % 32 == 0).
    • Supported element types are restricted per element width:
    • 4 bytes: uint32_t, int32_t, float
    • 2 bytes: uint16_t, int16_t, half, bfloat16_t
    • 1 byte: uint8_t, int8_t
    • The implementation operates over the static tile shape (TileDataSrc::Rows/Cols) and does not consult GetValidRow/GetValidCol.
  • Temporary tile:
    • The C++ API requires tmp. The tmp space size calculation formulas are as follows:
    • Basic parameters:
      • RowStride: 32 for b8 types, 16 for b16/b32 types (corresponding to Y_ELEM_B8 and Y_ELEM_OTHER)
      • ElemPerBlock: 32/sizeof(T), i.e., number of elements per 32-byte block
      • b8: uint8_t/int8_t, b16: uint16_t/int16_t/half/bfloat16_t, b32: uint32_t/int32_t/float
    • Alignment conditions:
      • When stride meets alignment requirements (dstStride % RowStride == 0, srcStride % ElemPerBlock == 0, srcStride/ElemPerBlock <= 255), tmp is used for efficient transpose; otherwise, scalar copy is used without needing tmp.
    • 2D Tile transpose [H, W] -> [W, H]: $$ \text{tmpSize} = W \times \lceil\frac{H}{\text{RowStride}}\rceil \times \text{RowStride} \times \text{sizeof(DType)} $$ where W is the column count (validCol), H is the row count (validRow). tmpStride must be aligned to RowStride. tmp is needed only when stride meets alignment conditions.
    • NCHW <-> NC1HWC0 bidirectional conversion:
      • Forward [N, C, H, W] -> [N, C1, H, W, C0]: $$ \text{tmpSize} = H \times W \times \lceil\frac{C0}{\text{RowStride}}\rceil \times \text{RowStride} \times \text{sizeof(DType)} $$ where C1 = (C + C0 - 1) / C0, transpose domain is C0 rows and H*W columns.
      • Reverse [N, C1, H, W, C0] -> [N, C, H, W]: $$ \text{tmpSize} = C0 \times \lceil\frac{H \times W}{\text{RowStride}}\rceil \times \text{RowStride} \times \text{sizeof(DType)} $$ transpose domain is H*W rows and C0 columns.
    • GNCHW <-> GNC1HWC0 bidirectional conversion:
      • Forward [G, N, C, H, W] -> [G, N, C1, H, W, C0]: $$ \text{tmpSize} = H \times W \times \lceil\frac{C0}{\text{RowStride}}\rceil \times \text{RowStride} \times \text{sizeof(DType)} $$ where C1 = (C + C0 - 1) / C0, transpose domain is C0 rows and H*W columns.
      • Reverse [G, N, C1, H, W, C0] -> [G, N, C, H, W]: $$ \text{tmpSize} = C0 \times \lceil\frac{H \times W}{\text{RowStride}}\rceil \times \text{RowStride} \times \text{sizeof(DType)} $$ transpose domain is H*W rows and C0 columns.
    • NC1HWC0 -> FRACTAL_Z and GNC1HWC0 -> FRACTAL_Z:
      • These two conversions do not require tmp space, they directly execute memory reorganization operations.
    • NCDHW to Fractal_Z_3D [N, C, D, H, W] -> [D, C1, H, W, N1, N0, C0]: $$ \text{tmpSize} = (N \times C1 \times C0 \times H \times W + \max(N \times C1 \times C0 \times H \times W, H \times W \times \lceil\frac{C0}{\text{RowStride}}\rceil \times \text{RowStride})) \times \text{sizeof(DType)} $$ where C1 = (C + C0 - 1) / C0, N1 = (N + N0 - 1) / N0. RowStride is 32 for 8-bit data and 16 for 16/32-bit data. This conversion has two stages with different execution paths: first stage extracts NCDHW d-plane to NCHW format (needs NC1C0HW space for planePtr), second stage either writes result to secondPtr (needs NC1C0HW) or uses secondPtr as transpose tmp (needs HWceil(C0/RowStride)*RowStride). Since the path is chosen at runtime, secondPtr requires max of both sizes.
  • ConvTile:
    • Transpose of ConvTile for TileType::Vec is supported。 Element size must be 1、2 or 4 bytes. Supported element types are uint32_t、int32_t、float、uint16_t、int16_t、half、bfloat16_t、uint8_t、int8_t.
    • Format transformation from NCHW to NC1HWC0 is supported, while C1 == (C + C0 - 1)/C0，HW matches alignment constraint，which means H*W*sizeof(T)==0. C0 means c0_size, which C0 * sizeof(T) == 32。C0 can also be 4.
    • Format transformation from NC1HWC0 to FRACTAL_Z is supported， while N1 == (N + N0 - 1)/N0。N0 should be 16.
    • Format transformation from NCDHW to FRACTAL_Z_3D is supported, with the destination shape [D * C1 * H * W, N1, N0, C0], where C1 == (C + C0 - 1)/C0 and N1 == (N + N0 - 1)/N0. N0 is 16. C0 depends on element width: 64 for 4-bit data, 32 for 8-bit data, 16 for 16-bit data and 8 for 32-bit data. See the Temporary tile section above for the tmp size calculation formula.

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 TmpT = Tile<TileType::Vec, float, 16, 16>;
  SrcT src;
  DstT dst;
  TmpT tmp;
  TTRANS(dst, src, tmp);
}

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 TmpT = Tile<TileType::Vec, float, 16, 16>;
  SrcT src;
  DstT dst;
  TmpT tmp;
  TASSIGN(src, 0x1000);
  TASSIGN(dst, 0x2000);
  TASSIGN(tmp, 0x3000);
  TTRANS(dst, src, tmp);
}

ASM Form Examples

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.ttrans %src : !pto.tile<...> -> !pto.tile<...>

Manual Mode

# Manual mode: resources must be bound explicitly before issuing the instruction.
# Optional for tile operands:
# pto.tassign %arg0, @tile(0x1000)
# pto.tassign %arg1, @tile(0x2000)
%dst = pto.ttrans %src : !pto.tile<...> -> !pto.tile<...>

PTO Assembly Form

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