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<!---======================= begin_copyright_notice ============================
Copyright (C) 2020-2022 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ==========================-->
## Opcode
OWORD_LD_UNALIGNED = 0x3c
## Format
| | | | | | |
| --- | --- | --- | --- | --- | --- |
| 0x3c(OWORD_LD_UNALIGNED) | Size | Is_modified | Surface | Offset | Dst |
## Semantics
```
for (i = 0; i < num_owords; ++i) {
dst[i] = surface[offset+i]; //16 byte, dword-aligned
}
```
## Description
```
Reads contiguous owords (one oword is 16 byte) from <surface> starting at <offset>, and stores the result into <dst>. This instruction is identical to OWORD_LD, except that the offset is dword-aligned instead of oword-aligned. The execution mask is set to 'NoMask' (i.e., every element is returned).
```
- **Size(ub):**
- Bit[2..0]: Number of owords to read
- 0b000: 1 oword
- 0b001: 2 owords
- 0b010: 4 owords
- 0b011: 8 owords
- {XEHP+}0b100: 16 owords. may only be used when surface is T0
- **Is_modified(ub):** The field is ignored, the read always return the last write from this thread
- **Surface(ub):** Index of the surface variable. It must be a buffer.
- T0 (SLM): {ICLLP+} Yes. No for earlier platforms.
- T5 (stateless): yes
- **Offset(scalar):** The offset of the read in bytes. Must have type UD
- **Dst(raw_operand):** The raw operand of a general variable storing the results of the read
#### Properties
- **Out-of-bound Access:** On read: zeros are returned.
## Text
```
OWORD_LD_UNALIGNED (<size>) <surface> <offset> <dst>
```
|
