TMATMUL_ACC

Instruction Diagram

Introduction

Matrix multiplication with accumulator input (fused accumulation).

Mathematical Semantics

Assume:

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

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

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

Assembly Syntax

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<...>)

C++ Built-in APIs

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

The public include header is <pto/pto-inst.hpp>, and the internal declaration is located in 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); // Note: This overload uses cMatrix as both the accumulator input and output (in-place), reads its existing value as C0, and writes back C1 = C0 + A·B; it neither clears nor overwrites it.

Constraints

• All constraints from TMATMUL apply to the (cOutMatrix, aMatrix, bMatrix) triple.
• Implementation notes (Atlas A2/A3 training products/Atlas A2/A3 inference products/Ascend 950PR/Ascend 950DT):
  • TMATMUL_ACC_IMPL uses aMatrix.GetValidRow(), aMatrix.GetValidCol(), and bMatrix.GetValidCol() as m/k/n.
  • cInMatrix is not validated through explicit assertions in the current implementation (target-defined behavior).

Examples

Automatic

#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);
}

ASM Examples

Automatic Mode

# Automatic mode: the compiler/runtime is responsible for resource placement and scheduling.
%c_out = pto.tmatmul.acc %c_in, %a, %b : (!pto.tile<...>, !pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

Manual Mode

# Manual mode: explicitly bind resources first, then issue the instruction.
# Optional (when the instruction contains 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<...>)