Atlas - SDL_simd.h
Home / ext / SDL2 / src / cpuinfo
Lines: 1 | Size: 3579 bytes
[Download] [Show on GitHub] [Search similar files] [Raw] [Raw (proxy)] 
[FILE BEGIN]
1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21
22#include "SDL.h"
23#include "../SDL_internal.h"
24
25/**
26 * \brief Report the alignment this system needs for SIMD allocations.
27 *
28 * This will return the minimum number of bytes to which a pointer must be
29 *  aligned to be compatible with SIMD instructions on the current machine.
30 *  For example, if the machine supports SSE only, it will return 16, but if
31 *  it supports AVX-512F, it'll return 64 (etc). This only reports values for
32 *  instruction sets SDL knows about, so if your SDL build doesn't have
33 *  SDL_HasAVX512F(), then it might return 16 for the SSE support it sees and
34 *  not 64 for the AVX-512 instructions that exist but SDL doesn't know about.
35 *  Plan accordingly.
36 */
37extern size_t SDL_SIMDGetAlignment(void);
38
39/**
40 * \brief Allocate memory in a SIMD-friendly way.
41 *
42 * This will allocate a block of memory that is suitable for use with SIMD
43 *  instructions. Specifically, it will be properly aligned and padded for
44 *  the system's supported vector instructions.
45 *
46 * The memory returned will be padded such that it is safe to read or write
47 *  an incomplete vector at the end of the memory block. This can be useful
48 *  so you don't have to drop back to a scalar fallback at the end of your
49 *  SIMD processing loop to deal with the final elements without overflowing
50 *  the allocated buffer.
51 *
52 * You must free this memory with SDL_FreeSIMD(), not free() or SDL_free()
53 *  or delete[], etc.
54 *
55 * Note that SDL will only deal with SIMD instruction sets it is aware of;
56 *  for example, SDL 2.0.8 knows that SSE wants 16-byte vectors
57 *  (SDL_HasSSE()), and AVX2 wants 32 bytes (SDL_HasAVX2()), but doesn't
58 *  know that AVX-512 wants 64. To be clear: if you can't decide to use an
59 *  instruction set with an SDL_Has*() function, don't use that instruction
60 *  set with memory allocated through here.
61 *
62 * SDL_AllocSIMD(0) will return a non-NULL pointer, assuming the system isn't
63 *  out of memory.
64 *
65 *  \param len The length, in bytes, of the block to allocated. The actual
66 *             allocated block might be larger due to padding, etc.
67 * \return Pointer to newly-allocated block, NULL if out of memory.
68 *
69 * \sa SDL_SIMDAlignment
70 * \sa SDL_SIMDFree
71 */
72extern void * SDL_SIMDAlloc(const size_t len);
73
74/**
75 * \brief Deallocate memory obtained from SDL_SIMDAlloc
76 *
77 * It is not valid to use this function on a pointer from anything but
78 *  SDL_SIMDAlloc(). It can't be used on pointers from malloc, realloc,
79 *  SDL_malloc, memalign, new[], etc.
80 *
81 * However, SDL_SIMDFree(NULL) is a legal no-op.
82 *
83 * \sa SDL_SIMDAlloc
84 */
85extern void SDL_SIMDFree(void *ptr);
86
87/* vi: set ts=4 sw=4 expandtab: */
88
89
[FILE END]
(C) 2025 0x4248
(C) 2025 4248 Media and 4248 Systems, All part of 0x4248
See LICENCE files for more information. Not all files are by 0x4248 always check Licencing.