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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [libgloss/] [m68k/] [idp-inbyte.c] - Blame information for rev 258

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Line No. Rev Author Line
1 207 jeremybenn
/* idp-inbyte.c --
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 * Copyright (c) 1995 Cygnus Support
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 *
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 * The authors hereby grant permission to use, copy, modify, distribute,
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 * and license this software and its documentation for any purpose, provided
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 * that existing copyright notices are retained in all copies and that this
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 * notice is included verbatim in any distributions. No written agreement,
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 * license, or royalty fee is required for any of the authorized uses.
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 * Modifications to this software may be copyrighted by their authors
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 * and need not follow the licensing terms described here, provided that
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 * the new terms are clearly indicated on the first page of each file where
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 * they apply.
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 */
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#include <_ansi.h>
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#include "mc68681reg.h"
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/*
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 * The DUART is mapped into the IDP address space in an unusual
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 * manner.  The mc68681 is an 8 bit device located on the least
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 * significant byte (byte0) of the data bus.  Bytes 3, 2, and
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 * one have nothing in them and writes to these locations are
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 * not valid.
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 */
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#define DUART_ADDR      0x00B00000
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#define READREG(x)      (*((volatile char *) DUART_ADDR + (x * 4) + 3))
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#define WRITEREG(x, y)  (*((char *) DUART_ADDR + (x * 4) + 3) = y)
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/*
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 * inbyte -- get a byte from the DUART RX buffer. This only reads
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 *           from channel A
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 */
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char
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_DEFUN_VOID (inbyte)
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{
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  while ((READREG (DUART_SRA) & 0x01) == 0x00)
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    ;
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  return (READREG (DUART_RBA));         /* read the byte */
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}

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