pto.tmax

pto.tmax is part of the Elementwise Tile Tile instruction set.

Summary

Elementwise maximum of two tiles.

Mechanism

Elementwise maximum of two tiles.

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

\[ \mathrm{dst}_{i,j} = \max(\mathrm{src0}_{i,j}, \mathrm{src1}_{i,j}) \]

Syntax

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

Synchronous form:

%dst = tmax %src0, %src1 : !pto.tile<...>

AS Level 1 (SSA)

%dst = pto.tmax %src0, %src1 : (!pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

AS Level 2 (DPS)

pto.tmax ins(%src0, %src1 : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

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

template <typename TileDataDst, typename TileDataSrc0, typename TileDataSrc1, typename... WaitEvents>
PTO_INST RecordEvent TMAX(TileDataDst &dst, TileDataSrc0 &src0, TileDataSrc1 &src1, WaitEvents &... events);

Inputs

Operand Role Description
%src0 Left tile First source tile; read at (i, j) for each (i, j) in dst valid region
%src1 Right tile Second source tile; read at (i, j) for each (i, j) in dst valid region
WaitEvents... Optional synchronisation RecordEvent tokens to wait on before issuing the operation

Expected Outputs

Result Type Description
%dst !pto.tile<...> Destination tile; all (i, j) in its valid region contain max(src0[i,j], src1[i,j]) after the operation

Side Effects

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

Constraints

Constraints

  • Valid region:
    • The op uses dst.GetValidRow() / dst.GetValidCol() as the iteration domain; src0/src1 are assumed to be compatible (not validated by explicit runtime checks in this op).

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):

    • TileData::DType must be one of: int32_t, int16_t, half, float.
    • Tile layout must be row-major (TileData::isRowMajor).
    • Tile location must be vector (TileData::Loc == TileType::Vec).
    • Static valid bounds: TileData::ValidRow <= TileData::Rows and TileData::ValidCol <= TileData::Cols.
    • Runtime: src0, src1 and dst tiles should have the same validRow/validCol.

  • Implementation checks (A5):

    • TileData::DType must be one of: uint32_t, int32_t, uint16_t, int16_t, uint8_t, int8_t, float, half.
    • Tile layout must be row-major (TileData::isRowMajor).
    • Tile location must be vector (TileData::Loc == TileType::Vec).
    • Static valid bounds: TileData::ValidRow <= TileData::Rows and TileData::ValidCol <= TileData::Cols.
    • Runtime: src0, src1 and dst tiles should have the same validRow/validCol.

Performance

A2/A3 Throughput

TMAX compiles to CCE vector instructions via the TBinOp.hpp performance model. The throughput is identical to TADD (binary arithmetic):

Metric Value (FP) Value (INT)
Startup latency 14 14
Completion latency 19 17
Per-repeat throughput 2 2
Pipeline interval 18 18

Examples

Auto

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  TileT src0, src1, dst;
  TMAX(dst, src0, src1);
}

Manual

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using TileT = Tile<TileType::Vec, float, 16, 16>;
  TileT src0, src1, dst;
  TASSIGN(src0, 0x1000);
  TASSIGN(src1, 0x2000);
  TASSIGN(dst,  0x3000);
  TMAX(dst, src0, src1);
}

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.tmax %src0, %src1 : (!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)
%dst = pto.tmax %src0, %src1 : (!pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

PTO Assembly Form

%dst = tmax %src0, %src1 : !pto.tile<...>
# AS Level 2 (DPS)
pto.tmax ins(%src0, %src1 : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)