20000317 sourceware import

libgloss/rs6000/mbx-inbyte.c

@@ -0,0 +1,60 @@
+/*
+ * mbx-inbyte.c -- inbyte function for targets using the eppcbug monitor
+ *
+ * Copyright (c) 1998 Cygnus Support
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+#include "ppc-asm.h"
+
+int inbyte(void)
+{
+    struct {
+	unsigned clun;
+	unsigned dlun;
+	char     *data;
+	unsigned len;
+	unsigned rsrvd;
+	char     buf[4];
+    } ipb, *inpb;
+
+    struct {
+	int status;
+	int cnt;
+    } opb, *outpb;
+
+    inpb = &ipb;
+    outpb = &opb;
+
+    do {
+	inpb->clun = 0;
+	inpb->dlun = 0;
+	inpb->data = ipb.buf;
+	inpb->len  = 1;
+	inpb->rsrvd = 0;
+
+	asm volatile (
+            "mr  3,%0\n"
+	    "mr  4,%1\n"
+	    "li  10,0x200\n"
+	    "sc"
+	    : /* no outputs */
+	    : "r" (inpb), "r" (outpb)
+	    : "3", "4", "10"
+	);
+    } while (outpb->status == 0 && outpb->cnt == 0);
+
+    if (outpb->status == 0)
+	return ipb.buf[0] & 0xff;
+
+    return -1;
+}