Index: third_party/zlib/x86.c |
diff --git a/third_party/zlib/x86.c b/third_party/zlib/x86.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..35ec51624afd850ee70864636d4198685106f245 |
--- /dev/null |
+++ b/third_party/zlib/x86.c |
@@ -0,0 +1,112 @@ |
+/* |
+ * x86 feature check |
+ * |
+ * Copyright (C) 2013 Intel Corporation. All rights reserved. |
+ * Author: |
+ * Jim Kukunas |
+ * |
+ * For conditions of distribution and use, see copyright notice in zlib.h |
+ */ |
+ |
+#include "x86.h" |
+ |
+int x86_cpu_enable_simd; |
+ |
+#ifndef _MSC_VER |
+#include <pthread.h> |
+ |
+pthread_once_t cpu_check_inited_once = PTHREAD_ONCE_INIT; |
+static void _x86_check_features(void); |
+ |
+void x86_check_features(void) |
+{ |
+ pthread_once(&cpu_check_inited_once, _x86_check_features); |
+} |
+ |
+static void _x86_check_features(void) |
+{ |
+ int x86_cpu_has_sse2; |
+ int x86_cpu_has_sse42; |
+ int x86_cpu_has_pclmulqdq; |
+ unsigned eax, ebx, ecx, edx; |
+ |
+ eax = 1; |
+#ifdef __i386__ |
+ __asm__ __volatile__ ( |
+ "xchg %%ebx, %1\n\t" |
+ "cpuid\n\t" |
+ "xchg %1, %%ebx\n\t" |
+ : "+a" (eax), "=S" (ebx), "=c" (ecx), "=d" (edx) |
+ ); |
+#else |
+ __asm__ __volatile__ ( |
+ "cpuid\n\t" |
+ : "+a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) |
+ ); |
+#endif /* (__i386__) */ |
+ |
+ x86_cpu_has_sse2 = edx & 0x4000000; |
+ x86_cpu_has_sse42 = ecx & 0x100000; |
+ x86_cpu_has_pclmulqdq = ecx & 0x2; |
+ |
+ x86_cpu_enable_simd = x86_cpu_has_sse2 && |
+ x86_cpu_has_sse42 && |
+ x86_cpu_has_pclmulqdq; |
+} |
+#else |
+#include <intrin.h> |
+#include <windows.h> |
+#include <stdint.h> |
+ |
+static volatile int32_t once_control = 0; |
+static void _x86_check_features(void); |
+static int fake_pthread_once(volatile int32_t *once_control, |
+ void (*init_routine)(void)); |
+ |
+void x86_check_features(void) |
+{ |
+ fake_pthread_once(&once_control, _x86_check_features); |
+} |
+ |
+/* Copied from "perftools_pthread_once" in tcmalloc */ |
+static int fake_pthread_once(volatile int32_t *once_control, |
+ void (*init_routine)(void)) { |
+ // Try for a fast path first. Note: this should be an acquire semantics read |
+ // It is on x86 and x64, where Windows runs. |
+ if (*once_control != 1) { |
+ while (1) { |
+ switch (InterlockedCompareExchange(once_control, 2, 0)) { |
+ case 0: |
+ init_routine(); |
+ InterlockedExchange(once_control, 1); |
+ return 0; |
+ case 1: |
+ // The initializer has already been executed |
+ return 0; |
+ default: |
+ // The initializer is being processed by another thread |
+ SwitchToThread(); |
+ } |
+ } |
+ } |
+ return 0; |
+} |
+ |
+static void _x86_check_features(void) |
+{ |
+ int x86_cpu_has_sse2; |
+ int x86_cpu_has_sse42; |
+ int x86_cpu_has_pclmulqdq; |
+ int regs[4]; |
+ |
+ __cpuid(regs, 1); |
+ |
+ x86_cpu_has_sse2 = regs[3] & 0x4000000; |
+ x86_cpu_has_sse42= regs[2] & 0x100000; |
+ x86_cpu_has_pclmulqdq = regs[2] & 0x2; |
+ |
+ x86_cpu_enable_simd = x86_cpu_has_sse2 && |
+ x86_cpu_has_sse42 && |
+ x86_cpu_has_pclmulqdq; |
+} |
+#endif /* _MSC_VER */ |