CPU feature detection and assembly helpers

cpu.cpp

@@ -0,0 +1,172 @@
+// cpu.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "cpu.h"
+
+#include "misc.h"
+#include <algorithm>
+
+#ifdef __GNUC__
+#include <signal.h>
+#include <setjmp.h>
+#endif
+
+NAMESPACE_BEGIN(CryptoPP)
+
+#ifdef CRYPTOPP_X86_ASM_AVAILABLE
+
+typedef void (*SigHandler)(int);
+
+static jmp_buf s_jmpNoCPUID;
+static void SigIllHandlerCPUID(int)
+{
+	longjmp(s_jmpNoCPUID, 1);
+}
+
+bool CpuId(word32 input, word32 *output)
+{
+#ifdef _MSC_VER
+    __try
+	{
+		__asm
+		{
+			mov eax, input
+			cpuid
+			mov edi, output
+			mov [edi], eax
+			mov [edi+4], ebx
+			mov [edi+8], ecx
+			mov [edi+12], edx
+		}
+	}
+    __except (1)
+	{
+		return false;
+    }
+	return true;
+#else
+	SigHandler oldHandler = signal(SIGILL, SigIllHandlerCPUID);
+	if (oldHandler == SIG_ERR)
+		return false;
+
+	bool result = true;
+	if (setjmp(s_jmpNoCPUID))
+		result = false;
+	else
+	{
+		__asm__
+		(
+			// save ebx in case -fPIC is being used
+			"push %%ebx; cpuid; mov %%ebx, %%edi; pop %%ebx"
+			: "=a" (output[0]), "=D" (output[1]), "=c" (output[2]), "=d" (output[3])
+			: "a" (input)
+		);
+	}
+
+	signal(SIGILL, oldHandler);
+	return result;
+#endif
+}
+
+#ifndef _MSC_VER
+static jmp_buf s_jmpNoSSE2;
+static void SigIllHandlerSSE2(int)
+{
+	longjmp(s_jmpNoSSE2, 1);
+}
+#endif
+
+#elif _MSC_VER >= 1400
+
+bool CpuId(word32 input, word32 *output)
+{
+	__cpuid((int *)output, input);
+	return true;
+}
+
+inline bool TrySSE2()
+{
+	return true;
+}
+
+#endif
+
+#ifdef CRYPTOPP_CPUID_AVAILABLE
+
+static bool TrySSE2()
+{
+#ifdef _MSC_VER
+    __try
+	{
+#if CRYPTOPP_BOOL_SSE2_ASM_AVAILABLE
+        __asm por xmm0, xmm0        // executing SSE2 instruction
+#elif CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
+		__mm128i x = _mm_setzero_si128();
+		return _mm_cvtsi128_si32(x) == 0;
+#endif
+	}
+    __except (1)
+	{
+		return false;
+    }
+	return true;
+#elif defined(__GNUC__)
+	SigHandler oldHandler = signal(SIGILL, SigIllHandlerSSE2);
+	if (oldHandler == SIG_ERR)
+		return false;
+
+	bool result = true;
+	if (setjmp(s_jmpNoSSE2))
+		result = false;
+	else
+	{
+#if CRYPTOPP_BOOL_SSE2_ASM_AVAILABLE
+		__asm __volatile ("por %xmm0, %xmm0");
+#elif CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
+		__mm128i x = _mm_setzero_si128();
+		result = _mm_cvtsi128_si32(x) == 0;
+#endif
+	}
+
+	signal(SIGILL, oldHandler);
+	return result;
+#else
+	return false;
+#endif
+}
+
+bool g_x86DetectionDone = false;
+bool g_hasSSE2 = false, g_hasSSSE3 = false, g_hasMMX = false, g_isP4 = false;
+int g_cacheLineSize = CRYPTOPP_L1_CACHE_LINE_SIZE;
+
+void DetectX86Features()
+{
+	word32 cpuid[4], cpuid1[4];
+	if (!CpuId(0, cpuid))
+		return;
+	if (!CpuId(1, cpuid1))
+		return;
+
+	g_hasMMX = (cpuid1[3] & (1 << 23)) != 0;
+	if ((cpuid1[3] & (1 << 26)) != 0)
+		g_hasSSE2 = TrySSE2();
+	g_hasSSSE3 = g_hasSSE2 && (cpuid1[2] & (1<<9));
+
+	std::swap(cpuid[2], cpuid[3]);
+	if (memcmp(cpuid+1, "GenuineIntel", 12) == 0)
+	{
+		g_isP4 = ((cpuid1[0] >> 8) & 0xf) == 0xf;
+		g_cacheLineSize = 8 * GETBYTE(cpuid1[1], 1);
+	}
+	else if (memcmp(cpuid+1, "AuthenticAMD", 12) == 0)
+	{
+		CpuId(0x80000005, cpuid);
+		g_cacheLineSize = GETBYTE(cpuid[2], 0);
+	}
+
+	g_x86DetectionDone = true;
+}
+
+#endif
+
+NAMESPACE_END

cpu.h

@@ -0,0 +1,111 @@
+#ifndef CRYPTOPP_CPU_H
+#define CRYPTOPP_CPU_H
+
+#include "config.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+#if defined(CRYPTOPP_X86_ASM_AVAILABLE) || _MSC_VER >= 1400
+
+#define CRYPTOPP_CPUID_AVAILABLE
+
+// these should not be used directly
+extern bool g_x86DetectionDone;
+extern bool g_hasSSE2, g_hasMMX, g_hasSSSE3, g_isP4;
+extern int g_cacheLineSize;
+void DetectX86Features();
+
+bool CpuId(word32 input, word32 *output);
+
+#if !CRYPTOPP_BOOL_X64
+
+inline bool HasSSE2()
+{
+	if (!g_x86DetectionDone)
+		DetectX86Features();
+	return g_hasSSE2;
+}
+
+inline bool HasMMX()
+{
+	if (!g_x86DetectionDone)
+		DetectX86Features();
+	return g_hasMMX;
+}
+
+#endif
+
+inline bool HasSSSE3()
+{
+	if (!g_x86DetectionDone)
+		DetectX86Features();
+	return g_hasSSSE3;
+}
+
+inline bool IsP4()
+{
+	if (!g_x86DetectionDone)
+		DetectX86Features();
+	return g_isP4;
+}
+
+inline int GetCacheLineSize()
+{
+	if (!g_x86DetectionDone)
+		DetectX86Features();
+	return g_cacheLineSize;
+}
+
+#else
+
+inline int GetCacheLineSize()
+{
+	return CRYPTOPP_L1_CACHE_LINE_SIZE;
+}
+
+#endif		// #ifdef CRYPTOPP_X86_ASM_AVAILABLE || _MSC_VER >= 1400
+
+#if CRYPTOPP_BOOL_X64
+
+inline bool HasSSE2()
+{
+	return true;
+}
+
+inline bool HasMMX()
+{
+	return true;
+}
+
+#endif
+
+#if defined(__GNUC__)
+	// define these in two steps to allow arguments to be expanded
+	#define GNU_AS1(x) #x ";"
+	#define GNU_AS2(x, y) #x ", " #y ";"
+	#define GNU_AS3(x, y, z) #x ", " #y ", " #z ";"
+	#define GNU_ASL(x) "\n" #x ":"
+	#define GNU_ASJ(x, y, z) #x " " #y #z ";"
+	#define AS1(x) GNU_AS1(x)
+	#define AS2(x, y) GNU_AS2(x, y)
+	#define AS3(x, y, z) GNU_AS3(x, y, z)
+	#define ASS(x, y, a, b, c, d) #x ", " #y ", " #a "*64+" #b "*16+" #c "*4+" #d ";"
+	#define ASL(x) GNU_ASL(x)
+	#define ASJ(x, y, z) GNU_ASJ(x, y, z)
+	#define ASC(x, y) #x " " #y ";"
+#else
+	#define AS1(x) __asm {x}
+	#define AS2(x, y) __asm {x, y}
+	#define AS3(x, y, z) __asm {x, y, z}
+	#define ASS(x, y, a, b, c, d) __asm {x, y, _MM_SHUFFLE(a, b, c, d)}
+	#define ASL(x) __asm {label##x:}
+	#define ASJ(x, y, z) __asm {x label##y}
+	#define ASC(x, y) __asm {x label##y}
+#endif
+
+// GNU assembler doesn't seem to have mod operator
+#define ASM_MOD(x, y) ((x)-((x)/(y))*(y))
+
+NAMESPACE_END
+
+#endif