--- db-4.2.52/dbinc/mutex.h.amd64-mutexes	2003-09-20 23:40:49.000000000 +0200
+++ db-4.2.52/dbinc/mutex.h	2004-02-25 14:25:43.000000000 +0100
@@ -781,6 +781,31 @@ typedef unsigned char tsl_t;
 #endif
 #endif
 
+/*********************************************************************
+ * amd64/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_AMD64_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * For gcc/amd64, 0 is clear, 1 is set.
+ */
+#define	MUTEX_SET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+	asm volatile("movq $1,%%rax; lock; xchgb %1,%%al; xorq $1,%%rax"\
+	    : "=&a" (__r), "=m" (*__l)					\
+	    : "1" (*__l)						\
+	    );								\
+	__r & 1;							\
+})
+
+#define	MUTEX_UNSET(tsl)	(*(tsl) = 0)
+#define	MUTEX_INIT(tsl)		MUTEX_UNSET(tsl)
+#endif
+#endif
+
 /*
  * Mutex alignment defaults to one byte.
  *
--- db-4.2.52/dist/aclocal/mutex.ac.amd64-mutexes	2003-06-16 16:54:39.000000000 +0200
+++ db-4.2.52/dist/aclocal/mutex.ac	2004-02-25 14:23:21.000000000 +0100
@@ -461,6 +461,17 @@ AC_TRY_COMPILE(,[
 ], [db_cv_mutex="ia64/gcc-assembly"])
 fi
 
+# amd64/gcc: Linux
+if test "$db_cv_mutex" = no; then
+AC_TRY_COMPILE(,[
+#if defined(__x86_64__) && defined(__GNUC__)
+	exit(0);
+#else
+	FAIL TO COMPILE/LINK
+#endif
+], [db_cv_mutex="amd64/gcc-assembly"])
+fi
+
 # uts/cc: UTS
 if test "$db_cv_mutex" = no; then
 AC_TRY_COMPILE(,[
@@ -511,6 +522,10 @@ ia64/gcc-assembly)	ADDITIONAL_OBJS="mut_
 			AC_DEFINE(HAVE_MUTEX_IA64_GCC_ASSEMBLY)
 			AH_TEMPLATE(HAVE_MUTEX_IA64_GCC_ASSEMBLY,
 			    [Define to 1 to use the GCC compiler and IA64 assembly language mutexes.]);;
+amd64/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
+			AC_DEFINE(HAVE_MUTEX_AMD64_GCC_ASSEMBLY)
+			AH_TEMPLATE(HAVE_MUTEX_AMD64_GCC_ASSEMBLY,
+			    [Define to 1 to use the GCC compiler and AMD64 assembly language mutexes.]);;
 POSIX/pthreads)		ADDITIONAL_OBJS="mut_pthread${o} $ADDITIONAL_OBJS"
 			AC_DEFINE(HAVE_MUTEX_PTHREADS)
 			AH_TEMPLATE(HAVE_MUTEX_PTHREADS,