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/*
* 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;
}
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