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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [libgloss/] [m68k/] [idp-outbyte.c] - Blame information for rev 840

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1 148 jeremybenn
/* idp-outbyte.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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 * raw_outbyte -- send a byte to the DUART buffer. This only sends
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 *           to channel A.
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 */
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static void
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_DEFUN (raw_outbyte, (byte),
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        char byte)
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{
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  /* First, wait for the UART to finish clocking out the last
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     character we sent, if any.  Then, give it the next character to
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     work on.  By waiting first, then handing off a new character, we
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     allow the UART to work while the processor (perhaps) does other
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     things; if we waited after sending each character, there'd be no
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     opportunity for parallelism.  */
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  while ((READREG (DUART_SRA) & 0x04) == 0x00)
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    ;
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  WRITEREG (DUART_TBA, byte);           /* write the byte */
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}
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/*
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 * outbyte -- send BYTE out the DUART's channel A, for display to
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 *      the user.
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 *
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 *      Normally, this is identical to raw_outbyte, but if
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 *      GDB_MONITOR_OUTPUT is #defined, we prefix each byte we send
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 *      with a ^O character (ASCII 15).  This is a signal to GDB's
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 *      `rom68k' target to pass the character directly on to the user;
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 *      it allows programs to do console output under GDB.
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 *
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 *      We compile this file twice: once with GDB_MONITOR_OUTPUT
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 *      #defined, and once without.  The former .o file we put in
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 *      libidpgdb.a, which is included in the link by idpgdb.ld; the
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 *      latter we put in libidp.a, which is selected by idp.ld.
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 */
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void
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_DEFUN (outbyte, (byte),
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        char byte)
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{
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#ifdef GDB_MONITOR_OUTPUT
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  raw_outbyte (0x0f);
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#endif
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  raw_outbyte (byte);
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}

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