TPREFETCH

Instruction Diagram

Introduction

Prefetches data from global memory into the tile local cache/buffer (implementation-defined). This is typically used to reduce latency before a subsequent TLOAD.

Note: Unlike most PTO instructions, TPREFETCH does not implicitly call TSYNC(events...) in the C++ wrapper.

Mathematical Semantics

Unless otherwise specified, the semantics are defined over the valid region, and target-specific behavior is marked as implementation-defined.

Assembly Syntax

Synchronous form:

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

AS Level 1 (SSA)

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

AS Level 2 (DPS)

pto.tprefetch ins(%src : !pto.global<...>) 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 TileData, typename GlobalData>
PTO_INST RecordEvent TPREFETCH(TileData &dst, GlobalData &src);

Constraints

The semantics and cache behavior are target/implementation-defined.
Some targets may ignore the prefetch and treat it as a hint.

Examples

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

ASM Examples

Automatic Mode

# Automatic mode: the compiler/runtime handles resource placement and scheduling.
%dst = pto.tprefetch %src : !pto.global<...> -> !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.tprefetch %src : !pto.global<...> -> !pto.tile<...>

PTO Assembly Form

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