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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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