pto.tmatmul_acc

pto.tmatmul_acc is part of the Matrix And Matrix Vector instruction set.

Summary

Matrix multiply with accumulator input (fused accumulate).

Mechanism

Matrix multiply with accumulator input (fused accumulate). It operates on tile payloads rather than scalar control state, and its legality is constrained by tile shape, layout, valid-region, and target-profile support.

Let:

  • M = aMatrix.GetValidRow()
  • K = aMatrix.GetValidCol()
  • N = bMatrix.GetValidCol()

For 0 <= i < M and 0 <= j < N:

\[ \mathrm{C1}_{i,j} = \mathrm{C0}_{i,j} + \sum_{k=0}^{K-1} \mathrm{A}_{i,k} \cdot \mathrm{B}_{k,j} \]

Syntax

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

Synchronous form:

%acc1 = tmatmul.acc %acc0, %a, %b : (!pto.tile<...>, !pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

AS Level 1 (SSA)

%c_out = pto.tmatmul.acc %c_in, %a, %b : (!pto.tile<...>, !pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

AS Level 2 (DPS)

pto.tmatmul.acc ins(%c_in, %a, %b : !pto.tile_buf<...>, !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%c_out : !pto.tile_buf<...>)

IR Level 1 (SSA)

%c_out = pto.tmatmul.acc %c_in, %a, %b : (!pto.tile<...>, !pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

IR Level 2 (DPS)

pto.tmatmul.acc ins(%c_in, %a, %b : !pto.tile_buf<...>, !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%c_out : !pto.tile_buf<...>)

C++ Intrinsic

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

template <typename TileRes, typename TileLeft, typename TileRight, typename... WaitEvents>
PTO_INST RecordEvent TMATMUL_ACC(TileRes &cOutMatrix, TileRes &cInMatrix, TileLeft &aMatrix, TileRight &bMatrix, WaitEvents &... events);

template <AccPhase Phase, typename TileRes, typename TileLeft, typename TileRight, typename... WaitEvents>
PTO_INST RecordEvent TMATMUL_ACC(TileRes &cOutMatrix, TileRes &cInMatrix, TileLeft &aMatrix, TileRight &bMatrix, WaitEvents &... events);

template <AccPhase Phase = AccPhase::Unspecified, typename TileRes, typename TileLeft, typename TileRight,
          typename... WaitEvents>
PTO_INST RecordEvent TMATMUL_ACC(TileRes &cMatrix, TileLeft &aMatrix, TileRight &bMatrix, WaitEvents &... events);

Inputs

  • cIn is the input accumulator tile.
  • a is the left operand tile (must be TileLeft location).
  • b is the right operand tile (must be TileRight location).
  • dst names the output accumulator tile. The operation iterates over dst's valid region.

Expected Outputs

dst holds the accumulated matrix multiply result: dst[i,j] = cIn[i,j] + sum over k of a[i,k] * b[k,j].

Side Effects

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

Constraints

Constraints

  • All constraints from TMATMUL apply to the (cOutMatrix, aMatrix, bMatrix) triple.

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 notes (A2A3/A5):
    • TMATMUL_ACC_IMPL uses aMatrix.GetValidRow(), aMatrix.GetValidCol(), and bMatrix.GetValidCol() for m/k/n.
    • cInMatrix is not validated by explicit assertions in the current implementations (target-defined behavior).

Examples

Auto

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using A = TileLeft<half, 16, 16>;
  using B = TileRight<half, 16, 16>;
  using C = TileAcc<float, 16, 16>;
  A a;
  B b;
  C c0, c1;
  TMATMUL_ACC(c1, c0, a, b);
}

Manual

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using A = TileLeft<half, 16, 16>;
  using B = TileRight<half, 16, 16>;
  using C = TileAcc<float, 16, 16>;
  A a;
  B b;
  C c0, c1;
  TASSIGN(a, 0x1000);
  TASSIGN(b, 0x2000);
  TASSIGN(c0, 0x3000);
  TASSIGN(c1, 0x4000);
  TMATMUL_ACC(c1, c0, a, b);
}

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%c_out = pto.tmatmul.acc %c_in, %a, %b : (!pto.tile<...>, !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)
%c_out = pto.tmatmul.acc %c_in, %a, %b : (!pto.tile<...>, !pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

PTO Assembly Form

%acc1 = tmatmul.acc %acc0, %a, %b : (!pto.tile<...>, !pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>
# AS Level 2 (DPS)
pto.tmatmul.acc ins(%c_in, %a, %b : !pto.tile_buf<...>, !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%c_out : !pto.tile_buf<...>)