target-alpha: implement getxuid and getxgid syscalls

This patch implemented the setxuid and setxgid syscalls for Alpha.
These syscalls return two values, both uid/euid and gid/egid.
In addition to returning the first value in $v0, the additional
value is returned in the $a4 register.

The syscalls are used instead of the separate syscalls for those values
used on other architectures (this is probably because Alpha Linux started
out syscall compatible with DEC/OSF/Tru64).

With this patch, the perlbmk benchmarks from Spec2000 run properly.

(Vince Weaver)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5722 c046a42c-6fe2-441c-8c8c-71466251a162

linux-user/syscall.c

@@ -5533,6 +5533,30 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         ret = get_errno(getuid());
         break;
 #endif
+
+#if defined(TARGET_NR_getxuid) && defined(TARGET_ALPHA)
+   /* Alpha specific */
+    case TARGET_NR_getxuid:
+	 {
+	    uid_t euid;
+	    euid=geteuid();
+	    ((CPUAlphaState *)cpu_env)->ir[IR_A4]=euid;
+	 }
+        ret = get_errno(getuid());
+        break;
+#endif
+#if defined(TARGET_NR_getxgid) && defined(TARGET_ALPHA)
+   /* Alpha specific */
+    case TARGET_NR_getxgid:
+	 {
+	    uid_t egid;
+	    egid=getegid();
+	    ((CPUAlphaState *)cpu_env)->ir[IR_A4]=egid;
+	 }
+        ret = get_errno(getgid());
+        break;
+#endif
+
 #ifdef TARGET_NR_getgid32
     case TARGET_NR_getgid32:
         ret = get_errno(getgid());