[PATCH 01/10] Enable AMD64 arcfour implementation on WIN64

[Jussi Kivilinna]

* cipher/arcfour-amd64.S: Enable when
HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS defined.
(ELF): New macro to mask lines with ELF specific commands.
* cipher/arcfour.c (USE_AMD64_ASM): Enable when
HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS defined.
(do_encrypt, do_decrypt) [HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS]: Use
assembly block to call AMD64 assembly function.
--

Signed-off-by: Jussi Kivilinna <jussi.kivilinna at iki.fi>
---
 cipher/arcfour-amd64.S |   13 ++++++++++---
 cipher/arcfour.c       |   17 ++++++++++++++++-
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/cipher/arcfour-amd64.S b/cipher/arcfour-amd64.S
index 8b8031a..2e52ea0 100644
--- a/cipher/arcfour-amd64.S
+++ b/cipher/arcfour-amd64.S
@@ -15,12 +15,19 @@
 
 #ifdef __x86_64__
 #include <config.h>
-#if defined(USE_ARCFOUR) && defined(HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS)
+#if defined(USE_ARCFOUR) && (defined(HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS) || \
+    defined(HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS))
+
+#ifdef HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS
+# define ELF(...) __VA_ARGS__
+#else
+# define ELF(...) /*_*/
+#endif
 
 .text
 .align 16
 .globl _gcry_arcfour_amd64
-.type _gcry_arcfour_amd64, at function
+ELF(.type _gcry_arcfour_amd64, at function)
 _gcry_arcfour_amd64:
 	push	%rbp
 	push	%rbx
@@ -91,7 +98,7 @@ _gcry_arcfour_amd64:
 	pop	%rbp
 	ret
 .L__gcry_arcfour_amd64_end:
-.size _gcry_arcfour_amd64,.L__gcry_arcfour_amd64_end-_gcry_arcfour_amd64
+ELF(.size _gcry_arcfour_amd64,.L__gcry_arcfour_amd64_end-_gcry_arcfour_amd64)
 
 #endif
 #endif
diff --git a/cipher/arcfour.c b/cipher/arcfour.c
index 27537bf..44e8ef4 100644
--- a/cipher/arcfour.c
+++ b/cipher/arcfour.c
@@ -33,7 +33,8 @@
 
 /* USE_AMD64_ASM indicates whether to use AMD64 assembly code. */
 #undef USE_AMD64_ASM
-#if defined(__x86_64__) && defined(HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS)
+#if defined(__x86_64__) && (defined(HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS) || \
+    defined(HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS))
 # define USE_AMD64_ASM 1
 #endif
 
@@ -53,7 +54,21 @@ static void
 encrypt_stream (void *context,
                 byte *outbuf, const byte *inbuf, size_t length)
 {
+#ifdef HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS
+  const void *fn = _gcry_arcfour_amd64;
+  /* Call SystemV ABI function without storing non-volatile XMM registers,
+   * as target function does not use vector instruction sets. */
+  asm volatile ("callq *%0\n\t"
+                : "+a" (fn),
+                  "+D" (context),
+                  "+S" (length),
+                  "+d" (inbuf),
+                  "+c" (outbuf)
+                :
+                : "cc", "memory", "r8", "r9", "r10", "r11");
+#else
   _gcry_arcfour_amd64 (context, length, inbuf, outbuf );
+#endif
 }
 
 #else /*!USE_AMD64_ASM*/