Add some basic prefetching support (only supported with GNU C++ or things

that claim to be by defining __GNUG__ (such as Intel C++)) in new utils
header prefetch.h

1 files changed, 39 insertions, 0 deletions

diff --git a/src/utils/prefetch.h b/src/utils/prefetch.h
new file mode 100644
index 000000000..100829dce
--- /dev/null
+++ b/src/utils/prefetch.h
@@ -0,0 +1,39 @@
+/*
+* Prefetching Operations
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_PREFETCH_H__
+#define BOTAN_PREFETCH_H__
+
+#include <botan/cpuid.h>
+
+namespace Botan {
+
+inline void prefetch_readonly(const void* addr_void, u32bit length)
+   {
+#if defined(__GNUG__)
+   const byte* addr = static_cast<const byte*>(addr_void);
+   const u32bit cl_size = CPUID::cache_line_size();
+
+   for(u32bit i = 0; i <= length; i += cl_size)
+      __builtin_prefetch(addr + i, 0);
+#endif
+   }
+
+inline void prefetch_readwrite(const void* addr_void, u32bit length)
+   {
+#if defined(__GNUG__)
+   const byte* addr = static_cast<const byte*>(addr_void);
+   const u32bit cl_size = CPUID::cache_line_size();
+
+   for(u32bit i = 0; i <= length; i += cl_size)
+      __builtin_prefetch(addr + i, 1);
+#endif
+   }
+
+}
+
+#endif