From 7fb5953055d14307a9d4ae95fd6499f3a48f8b95 Mon Sep 17 00:00:00 2001
From: Jeffrey Walton <noloader@gmail.com>
Date: Sat, 19 Aug 2017 15:41:45 -0400
Subject: Add VIA Padlock RNG

---
 padlkrng.cpp | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 padlkrng.cpp

(limited to 'padlkrng.cpp')

diff --git a/padlkrng.cpp b/padlkrng.cpp
new file mode 100644
index 00000000..ebe7d4f2
--- /dev/null
+++ b/padlkrng.cpp
@@ -0,0 +1,86 @@
+// via-rng.cpp - written and placed in public domain by Jeffrey Walton and Uri Blumenthal.
+
+#include "pch.h"
+#include "config.h"
+#include "cryptlib.h"
+#include "secblock.h"
+#include "padlkrng.h"
+#include "cpu.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+PadlockRNG::PadlockRNG()
+{
+#if CRYPTOPP_BOOL_X86
+    if (!HasPadlockRNG())
+		throw PadlockRNG_Err("HasPadlockRNG");
+#else
+	throw PadlockRNG_Err("HasPadlockRNG");
+#endif
+}
+
+void PadlockRNG::GenerateBlock(byte *output, size_t size)
+{
+	CRYPTOPP_UNUSED(output); CRYPTOPP_UNUSED(size);
+#if CRYPTOPP_BOOL_X86
+	while (size)
+	{
+# if defined(__GNUC__)
+
+		word32 result;
+		__asm__ __volatile__
+		(
+			"movl %1, %%edi          ;\n"
+			"movl $1, %%edx          ;\n"
+			".byte 0x0f, 0xa7, 0xc0  ;\n"
+			"andl $31, %%eax         ;\n"
+			"movl %%eax, %0          ;\n"
+
+			: "=g" (result) : "g" (m_buffer.begin()) : "eax", "edx", "edi", "cc"
+		);
+
+		const size_t rem = STDMIN(result, STDMIN(size, m_buffer.SizeInBytes()));
+		std::memcpy(output, m_buffer, rem);
+		size -= rem; output += rem;
+
+# elif defined(_MSC_VER)
+
+		word32 result;
+		byte* buffer = reinterpret_cast<byte*>(m_buffer.begin());
+
+		__asm {
+			mov edi, buffer
+			mov edx, 0x01
+			_emit 0x0f
+			_emit 0xa7
+			_emit 0xc0
+			and eax, 31
+			mov result, eax
+		}
+
+		const size_t rem = STDMIN(result, STDMIN(size, m_buffer.SizeInBytes()));
+		std::memcpy(output, m_buffer, rem);
+		size -= rem; output += rem;
+
+# else
+		throw NotImplemented("PadlockRNG::GenerateBlock");
+# endif
+	}
+#endif  // CRYPTOPP_BOOL_X86
+}
+
+void PadlockRNG::DiscardBytes(size_t n)
+{
+    FixedSizeSecBlock<word32, 4> discard;
+    n = RoundUpToMultipleOf(n, sizeof(word32));
+
+    size_t count = STDMIN(n, discard.SizeInBytes());
+    while (count)
+    {
+        GenerateBlock(discard.BytePtr(), count);
+        n -= count;
+        count = STDMIN(n, discard.SizeInBytes());
+    }
+}
+
+NAMESPACE_END
-- 
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