diff SDL3/SDL_cpuinfo.h @ 1:20d02a178406 default tip

*: check in everything else yay
author Paper <paper@tflc.us>
date Mon, 05 Jan 2026 02:15:46 -0500
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+++ b/SDL3/SDL_cpuinfo.h	Mon Jan 05 02:15:46 2026 -0500
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+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/* WIKI CATEGORY: CPUInfo */
+
+/**
+ * # CategoryCPUInfo
+ *
+ * CPU feature detection for SDL.
+ *
+ * These functions are largely concerned with reporting if the system has
+ * access to various SIMD instruction sets, but also has other important info
+ * to share, such as system RAM size and number of logical CPU cores.
+ *
+ * CPU instruction set checks, like SDL_HasSSE() and SDL_HasNEON(), are
+ * available on all platforms, even if they don't make sense (an ARM processor
+ * will never have SSE and an x86 processor will never have NEON, for example,
+ * but these functions still exist and will simply return false in these
+ * cases).
+ */
+
+#ifndef SDL_cpuinfo_h_
+#define SDL_cpuinfo_h_
+
+#include <SDL3/SDL_stdinc.h>
+
+#include <SDL3/SDL_begin_code.h>
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * A guess for the cacheline size used for padding.
+ *
+ * Most x86 processors have a 64 byte cache line. The 64-bit PowerPC
+ * processors have a 128 byte cache line. We use the larger value to be
+ * generally safe.
+ *
+ * \since This macro is available since SDL 3.2.0.
+ */
+#define SDL_CACHELINE_SIZE  128
+
+/**
+ * Get the number of logical CPU cores available.
+ *
+ * \returns the total number of logical CPU cores. On CPUs that include
+ *          technologies such as hyperthreading, the number of logical cores
+ *          may be more than the number of physical cores.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_GetNumLogicalCPUCores(void);
+
+/**
+ * Determine the L1 cache line size of the CPU.
+ *
+ * This is useful for determining multi-threaded structure padding or SIMD
+ * prefetch sizes.
+ *
+ * \returns the L1 cache line size of the CPU, in bytes.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_GetCPUCacheLineSize(void);
+
+/**
+ * Determine whether the CPU has AltiVec features.
+ *
+ * This always returns false on CPUs that aren't using PowerPC instruction
+ * sets.
+ *
+ * \returns true if the CPU has AltiVec features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasAltiVec(void);
+
+/**
+ * Determine whether the CPU has MMX features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has MMX features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasMMX(void);
+
+/**
+ * Determine whether the CPU has SSE features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has SSE features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasSSE2
+ * \sa SDL_HasSSE3
+ * \sa SDL_HasSSE41
+ * \sa SDL_HasSSE42
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasSSE(void);
+
+/**
+ * Determine whether the CPU has SSE2 features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has SSE2 features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasSSE
+ * \sa SDL_HasSSE3
+ * \sa SDL_HasSSE41
+ * \sa SDL_HasSSE42
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasSSE2(void);
+
+/**
+ * Determine whether the CPU has SSE3 features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has SSE3 features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasSSE
+ * \sa SDL_HasSSE2
+ * \sa SDL_HasSSE41
+ * \sa SDL_HasSSE42
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasSSE3(void);
+
+/**
+ * Determine whether the CPU has SSE4.1 features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has SSE4.1 features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasSSE
+ * \sa SDL_HasSSE2
+ * \sa SDL_HasSSE3
+ * \sa SDL_HasSSE42
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasSSE41(void);
+
+/**
+ * Determine whether the CPU has SSE4.2 features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has SSE4.2 features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasSSE
+ * \sa SDL_HasSSE2
+ * \sa SDL_HasSSE3
+ * \sa SDL_HasSSE41
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasSSE42(void);
+
+/**
+ * Determine whether the CPU has AVX features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has AVX features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasAVX2
+ * \sa SDL_HasAVX512F
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasAVX(void);
+
+/**
+ * Determine whether the CPU has AVX2 features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has AVX2 features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasAVX
+ * \sa SDL_HasAVX512F
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasAVX2(void);
+
+/**
+ * Determine whether the CPU has AVX-512F (foundation) features.
+ *
+ * This always returns false on CPUs that aren't using Intel instruction sets.
+ *
+ * \returns true if the CPU has AVX-512F features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasAVX
+ * \sa SDL_HasAVX2
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasAVX512F(void);
+
+/**
+ * Determine whether the CPU has ARM SIMD (ARMv6) features.
+ *
+ * This is different from ARM NEON, which is a different instruction set.
+ *
+ * This always returns false on CPUs that aren't using ARM instruction sets.
+ *
+ * \returns true if the CPU has ARM SIMD features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_HasNEON
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasARMSIMD(void);
+
+/**
+ * Determine whether the CPU has NEON (ARM SIMD) features.
+ *
+ * This always returns false on CPUs that aren't using ARM instruction sets.
+ *
+ * \returns true if the CPU has ARM NEON features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasNEON(void);
+
+/**
+ * Determine whether the CPU has LSX (LOONGARCH SIMD) features.
+ *
+ * This always returns false on CPUs that aren't using LOONGARCH instruction
+ * sets.
+ *
+ * \returns true if the CPU has LOONGARCH LSX features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasLSX(void);
+
+/**
+ * Determine whether the CPU has LASX (LOONGARCH SIMD) features.
+ *
+ * This always returns false on CPUs that aren't using LOONGARCH instruction
+ * sets.
+ *
+ * \returns true if the CPU has LOONGARCH LASX features or false if not.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC bool SDLCALL SDL_HasLASX(void);
+
+/**
+ * Get the amount of RAM configured in the system.
+ *
+ * \returns the amount of RAM configured in the system in MiB.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_GetSystemRAM(void);
+
+/**
+ * Report the alignment this system needs for SIMD allocations.
+ *
+ * This will return the minimum number of bytes to which a pointer must be
+ * aligned to be compatible with SIMD instructions on the current machine. For
+ * example, if the machine supports SSE only, it will return 16, but if it
+ * supports AVX-512F, it'll return 64 (etc). This only reports values for
+ * instruction sets SDL knows about, so if your SDL build doesn't have
+ * SDL_HasAVX512F(), then it might return 16 for the SSE support it sees and
+ * not 64 for the AVX-512 instructions that exist but SDL doesn't know about.
+ * Plan accordingly.
+ *
+ * \returns the alignment in bytes needed for available, known SIMD
+ *          instructions.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.2.0.
+ *
+ * \sa SDL_aligned_alloc
+ * \sa SDL_aligned_free
+ */
+extern SDL_DECLSPEC size_t SDLCALL SDL_GetSIMDAlignment(void);
+
+/**
+ * Report the size of a page of memory.
+ *
+ * Different platforms might have different memory page sizes. In current
+ * times, 4 kilobytes is not unusual, but newer systems are moving to larger
+ * page sizes, and esoteric platforms might have any unexpected size.
+ *
+ * Note that this function can return 0, which means SDL can't determine the
+ * page size on this platform. It will _not_ set an error string to be
+ * retrieved with SDL_GetError() in this case! In this case, defaulting to
+ * 4096 is often a reasonable option.
+ *
+ * \returns the size of a single page of memory, in bytes, or 0 if SDL can't
+ *          determine this information.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.4.0.
+ */
+extern SDL_DECLSPEC int SDLCALL SDL_GetSystemPageSize(void);
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include <SDL3/SDL_close_code.h>
+
+#endif /* SDL_cpuinfo_h_ */