TROWEXPANDEXPDIF

Instruction Diagram

Introduction

Row exponential difference operation: computes exp(src0 - src1), where src1 is a per-row scalar.

Mathematical Semantics

Assume R = dst.GetValidRow() and C = dst.GetValidCol(). Assume that s_i is the per-row scalar obtained from src1 (one value per row).

For 0 <= i < R and 0 <= j < C:

Assembly Syntax

Synchronous form:

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

AS Level 1 (SSA)

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

AS Level 2 (DPS)

pto.trowexpandexpdif ins(%src0, %src1 : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !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 TileDataDst, typename TileDataSrc0, typename TileDataSrc1, typename... WaitEvents>
PTO_INST RecordEvent TROWEXPANDEXPDIF(TileDataDst &dst, TileDataSrc0 &src0, TileDataSrc1 &src1, WaitEvents &... events);

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

Constraints

• TileDataDst::DType == TileDataSrc0::DType == TileDataSrc1::DType
• TileDataDst::DType, TileDataSrc0::DType, and TileDataSrc1::DType must be one of the following: half, float.
• Tile shape/layout constraint (compile time): TileDataDst::isRowMajor.
• Mode 1: src1 is expected to provide one scalar per row (that is, its effective shape must cover R values).
• Mode 2: src1 is expected to provide 32 bytes of data per row.
• The exact layout/fractal constraints are target-specific; see the backend headers under include/pto/npu/*/TRowExpand*.hpp.

Temporary Tile

The C++ API provides an overload that explicitly passes in TileDataTmp &tmp. This overload supports only mode 1 (ColMajor expanded operand, per-row scalar). In the internal implementation, TROWEXPANDEXPDIF is implemented by TROWEXPANDSUB followed by TEXP, so the tmp tile is used as the broadcast buffer for the SUB step.

• Atlas A2/A3 training products/Atlas A2/A3 inference products: The tmp tile is used as the broadcast buffer for the TROWEXPANDSUB step. The per-row scalar value of the ColMajor expanded operand is broadcast to the tmp buffer through the vbrcb instruction, creating a 32-byte block for each row, which is then used as the expanded operand in the subtraction operation. The repeat stride of the vbrcb instruction is 8 blocks (256 bytes), and each repeat processes 8 rows. The minimum tmp size is calculated as follows:
  • Common parameters:
    • R = dst.GetValidRow(), T = TileDataDst::DType.
  • When R < 256: $$\text{tmpSize} = \left\lceil\frac{R}{8}\right\rceil \times 256 \text{ bytes}$$
  • When R >= 256:
    • The operation uses a loop approach, with at most 30 repeats (240 rows) per loop. The tmp buffer is reused across loops, and each loop requires: $$\text{tmpSize} = 30 \times 256 = 7680 \text{ bytes}$$
  • For any mode 1 call, a compact shape-independent upper bound is 8 KB (8192 bytes).
  • The 3-parameter overload without tmp supports mode 1 and mode 2. For mode 1, it uses the internal 8 KB buffer (TMP_UB_OFFSET). For mode 2, no broadcast buffer is required.
• Ascend 950PR/Ascend 950DT: The tmp tile is accepted but not used ([[maybe_unused]]). The Ascend 950PR/Ascend 950DT hardware natively supports row broadcast through the broadcast mode of the vlds instruction, so no temporary buffer is required.

Examples

See the related examples in docs/isa/ and docs/coding/tutorials/.

ASM Examples

Automatic Mode

# Automatic mode: the compiler/runtime is responsible for resource placement and scheduling.
%dst = pto.trowexpandexpdif %src0, %src1 : !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)
%dst = pto.trowexpandexpdif %src0, %src1 : !pto.tile<...>, !pto.tile<...> -> !pto.tile<...>

PTO Assembly Form

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