source: trunk/libs/newlib/src/libgloss/rs6000/mbx-inbyte.c @ 684

Last change on this file since 684 was 444, checked in by satin@…, 7 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 1.4 KB
Line 
1/*
2 * mbx-inbyte.c -- inbyte function for targets using the eppcbug monitor
3 *
4 * Copyright (c) 1998 Cygnus Support
5 *
6 * The authors hereby grant permission to use, copy, modify, distribute,
7 * and license this software and its documentation for any purpose, provided
8 * that existing copyright notices are retained in all copies and that this
9 * notice is included verbatim in any distributions. No written agreement,
10 * license, or royalty fee is required for any of the authorized uses.
11 * Modifications to this software may be copyrighted by their authors
12 * and need not follow the licensing terms described here, provided that
13 * the new terms are clearly indicated on the first page of each file where
14 * they apply.
15 */
16
17#include "ppc-asm.h"
18
19int inbyte(void)
20{
21    struct {
22        unsigned clun;
23        unsigned dlun;
24        char     *data;
25        unsigned len;
26        unsigned rsrvd;
27        char     buf[4];
28    } ipb, *inpb;
29
30    struct {
31        int status;
32        int cnt;
33    } opb, *outpb;
34
35    inpb = &ipb;
36    outpb = &opb;
37
38    do {
39        inpb->clun = 0;
40        inpb->dlun = 0;
41        inpb->data = ipb.buf;
42        inpb->len  = 1;
43        inpb->rsrvd = 0;
44
45        asm volatile (
46            "mr  3,%0\n"
47            "mr  4,%1\n"
48            "li  10,0x200\n"
49            "sc"
50            : /* no outputs */
51            : "r" (inpb), "r" (outpb)
52            : "3", "4", "10"
53        );
54    } while (outpb->status == 0 && outpb->cnt == 0);
55
56    if (outpb->status == 0)
57        return ipb.buf[0] & 0xff;
58
59    return -1;
60}
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