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https://git.code.sf.net/p/fuse-emulator/fuse
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122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
/* ula.c: ULA routines
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Copyright (c) 1999-2004 Philip Kendall, Darren Salt
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$Id$
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Author contact information:
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E-mail: pak21-fuse@srcf.ucam.org
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Postal address: 15 Crescent Road, Wokingham, Berks, RG40 2DB, England
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*/
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#include <config.h>
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#include <libspectrum.h>
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#include "compat.h"
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#include "display.h"
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#include "keyboard.h"
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#include "machine.h"
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#include "settings.h"
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#include "sound.h"
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#include "tape.h"
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static libspectrum_byte last_byte;
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libspectrum_byte ula_contention[ 80000 ];
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libspectrum_byte
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ula_read( libspectrum_word port, int *attached )
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{
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*attached = 1;
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return ( keyboard_read( port >> 8 ) ^ ( tape_microphone ? 0x40 : 0x00 ) );
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}
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/* What happens when we write to the ULA? */
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void
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ula_write( libspectrum_word port GCC_UNUSED, libspectrum_byte b )
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{
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last_byte = b;
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display_set_lores_border( b & 0x07 );
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sound_beeper( 0, b & 0x10 );
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if( machine_current->timex ) {
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keyboard_default_value = 0x5f;
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return;
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}
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if( settings_current.issue2 ) {
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keyboard_default_value = b & 0x18 ? 0xff : 0xbf;
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} else {
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keyboard_default_value = b & 0x10 ? 0xff : 0xbf;
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}
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}
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libspectrum_byte
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ula_last_byte( void )
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{
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return last_byte;
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}
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int
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ula_from_snapshot( libspectrum_snap *snap )
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{
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ula_write( 0x00fe, libspectrum_snap_out_ula( snap ) );
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tstates = libspectrum_snap_tstates( snap );
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return 0;
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}
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int
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ula_to_snapshot( libspectrum_snap *snap )
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{
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libspectrum_snap_set_out_ula( snap, last_byte );
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libspectrum_snap_set_tstates( snap, tstates );
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return 0;
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}
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void
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ula_contend_port( libspectrum_word port )
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{
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if( machine_current->ram.port_contended( port ) ) {
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if( ( port & 0xc000 ) == 0x4000 ) {
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tstates += ula_contention[ tstates ]; tstates++;
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tstates += ula_contention[ tstates ]; tstates += 3;
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} else {
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tstates++;
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tstates += ula_contention[ tstates ]; tstates += 3;
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}
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} else {
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if( ( port & 0xc000 ) == 0x4000 ) {
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tstates += ula_contention[ tstates ]; tstates++;
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tstates += ula_contention[ tstates ]; tstates++;
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tstates += ula_contention[ tstates ]; tstates++;
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tstates += ula_contention[ tstates ]; tstates++;
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} else {
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tstates += 4;
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}
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}
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}
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