--- mstools/h/varargs.h	2018/08/09 18:23:08	1.1.1.3
+++ mstools/h/varargs.h	2018/08/09 18:25:27	1.1.1.4
@@ -21,7 +21,17 @@ extern "C" {
 #endif
 
 #ifndef _VA_LIST_DEFINED
+
+#ifdef _ALPHA_
+typedef struct {
+    char *a0;           /* pointer to first homed integer argument */
+    int offset;         /* byte offset of next parameter */
+} va_list;
+
+#else
 typedef char *va_list;
+#endif
+
 #define _VA_LIST_DEFINED
 #endif
 
@@ -60,6 +70,37 @@ typedef char *va_list;
 #endif
 
 
+#ifdef _ALPHA_
+
+/*
+ * The Alpha compiler supports two builtin functions that are used to
+ * implement stdarg/varargs.  The __builtin_va_start function is used
+ * by va_start to initialize the data structure that locates the next
+ * argument.  The __builtin_isfloat function is used by va_arg to pick
+ * which part of the home area a given register argument is stored in.
+ * The home area is where up to six integer and/or six floating point
+ * register arguments are stored down (so they can also be referenced
+ * by a pointer like any arguments passed on the stack).
+ */
+
+#ifdef __cplusplus
+extern __builtin_va_start(va_list, ...);
+#endif
+#define va_dcl long va_alist;
+#define va_start(list) __builtin_va_start(list, va_alist, 0)
+#define va_end(list)
+#define va_arg(list, mode) \
+    ( *(        ((list).offset += ((int)sizeof(mode) + 7) & -8) , \
+        (mode *)((list).a0 + (list).offset - \
+                    ((__builtin_isfloat(mode) && (list).offset <= (6 * 8)) ? \
+                        (6 * 8) + 8 : ((int)sizeof(mode) + 7) & -8) \
+                ) \
+       ) \
+    )
+
+#endif /* _ALPHA_ */
+
+
 #ifdef __cplusplus
 }
 #endif