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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [libgloss/] [m68k/] [idp-outbyte.c] - Rev 218
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/* idp-outbyte.c * Copyright (c) 1995 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 <_ansi.h> #include "mc68681reg.h" /* * The DUART is mapped into the IDP address space in an unusual * manner. The mc68681 is an 8 bit device located on the least * significant byte (byte0) of the data bus. Bytes 3, 2, and * one have nothing in them and writes to these locations are * not valid. */ #define DUART_ADDR 0x00B00000 #define READREG(x) (*((volatile char *) DUART_ADDR + (x * 4) + 3)) #define WRITEREG(x, y) (*((char *) DUART_ADDR + (x * 4) + 3) = y) /* * raw_outbyte -- send a byte to the DUART buffer. This only sends * to channel A. */ static void _DEFUN (raw_outbyte, (byte), char byte) { /* First, wait for the UART to finish clocking out the last character we sent, if any. Then, give it the next character to work on. By waiting first, then handing off a new character, we allow the UART to work while the processor (perhaps) does other things; if we waited after sending each character, there'd be no opportunity for parallelism. */ while ((READREG (DUART_SRA) & 0x04) == 0x00) ; WRITEREG (DUART_TBA, byte); /* write the byte */ } /* * outbyte -- send BYTE out the DUART's channel A, for display to * the user. * * Normally, this is identical to raw_outbyte, but if * GDB_MONITOR_OUTPUT is #defined, we prefix each byte we send * with a ^O character (ASCII 15). This is a signal to GDB's * `rom68k' target to pass the character directly on to the user; * it allows programs to do console output under GDB. * * We compile this file twice: once with GDB_MONITOR_OUTPUT * #defined, and once without. The former .o file we put in * libidpgdb.a, which is included in the link by idpgdb.ld; the * latter we put in libidp.a, which is selected by idp.ld. */ void _DEFUN (outbyte, (byte), char byte) { #ifdef GDB_MONITOR_OUTPUT raw_outbyte (0x0f); #endif raw_outbyte (byte); }
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