43ca8741b0
git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@809 6ac86273-5f31-0410-b378-82cca8765d1b
80 lines
3.4 KiB
C
80 lines
3.4 KiB
C
/****************************************************************/
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/* */
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/* break.c */
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/* FreeDOS */
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/* */
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/* Control Break detection and handling */
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/* */
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/* Copyright (c) 1999 */
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/* Steffen Kaiser */
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/* All Rights Reserved */
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/* */
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/* This file is part of DOS-C. */
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/* */
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/* DOS-C is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU General Public License */
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/* as published by the Free Software Foundation; either version */
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/* 2, or (at your option) any later version. */
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/* */
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/* DOS-C is distributed in the hope that it will be useful, but */
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/* WITHOUT ANY WARRANTY; without even the implied warranty of */
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/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See */
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/* the GNU General Public License for more details. */
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/* */
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/* You should have received a copy of the GNU General Public */
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/* License along with DOS-C; see the file COPYING. If not, */
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/* write to the Free Software Foundation, 675 Mass Ave, */
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/* Cambridge, MA 02139, USA. */
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/****************************************************************/
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#include "portab.h"
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#include "globals.h"
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#include "proto.h"
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extern void ASMCFUNC spawn_int23(void);
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#ifdef VERSION_STRINGS
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static BYTE *RcsId =
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"$Id$";
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#endif
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#define CB_FLG *(UBYTE FAR*)MK_FP(0x40, 0x71)
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#define CB_MSK 0x80
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/* Check for ^Break.
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* Two sources are available:
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* 1) flag at 40:71 bit 7
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* 2) STDIN stream via con_break()
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*/
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int check_handle_break(void)
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{
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if (CB_FLG & CB_MSK) {
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CB_FLG &= ~CB_MSK; /* reset the ^Break flag */
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handle_break(&syscon);
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}
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/* con_break will call handle_break() for CTL_C */
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return con_break();
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}
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/*
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* Handles a ^Break state
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*
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* Actions:
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* 1) clear the ^Break flag
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* 2) clear the STDIN stream
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* 3) decrease the InDOS flag as the kernel drops back to user space
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* 4) invoke INT-23 and never come back
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*/
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void handle_break(struct dhdr FAR **pdev)
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{
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echo_char(CTL_C, get_sft_idx(STDOUT));
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con_flush(pdev);
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if (!ErrorMode) /* within int21_handler, InDOS is not incremented */
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if (InDOS)
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--InDOS; /* fail-safe */
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spawn_int23(); /* invoke user INT-23 and never come back */
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}
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