kopia lustrzana https://github.com/Jean-MarcHarvengt/MCUME
270 wiersze
6.1 KiB
C
270 wiersze
6.1 KiB
C
/*
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** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
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**
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**
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** This program is free software; you can redistribute it and/or
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** modify it under the terms of version 2 of the GNU Library General
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** Public License as published by the Free Software Foundation.
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**
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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 GNU
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** Library General Public License for more details. To obtain a
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** copy of the GNU Library General Public License, write to the Free
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** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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**
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** Any permitted reproduction of these routines, in whole or in part,
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** must bear this legend.
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**
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**
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** map4.c
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**
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** mapper 4 interface
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** $Id: map004.c,v 1.2 2001/04/27 14:37:11 neil Exp $
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*/
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#include "noftypes.h"
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#include "nes_mmc.h"
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#include "nes.h"
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#include "libsnss.h"
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static struct
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{
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int counter, latch;
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bool enabled, reset;
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} irq;
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static uint8 reg;
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static uint8 command;
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static uint16 vrombase;
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/* mapper 4: MMC3 */
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static void map4_write(uint32 address, uint8 value)
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{
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switch (address & 0xE001)
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{
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case 0x8000:
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command = value;
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vrombase = (command & 0x80) ? 0x1000 : 0x0000;
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if (reg != (value & 0x40))
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{
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if (value & 0x40)
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mmc_bankrom(8, 0x8000, (mmc_getinfo()->rom_banks * 2) - 2);
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else
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mmc_bankrom(8, 0xC000, (mmc_getinfo()->rom_banks * 2) - 2);
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}
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reg = value & 0x40;
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break;
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case 0x8001:
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switch (command & 0x07)
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{
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case 0:
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value &= 0xFE;
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mmc_bankvrom(1, vrombase ^ 0x0000, value);
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mmc_bankvrom(1, vrombase ^ 0x0400, value + 1);
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break;
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case 1:
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value &= 0xFE;
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mmc_bankvrom(1, vrombase ^ 0x0800, value);
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mmc_bankvrom(1, vrombase ^ 0x0C00, value + 1);
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break;
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case 2:
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mmc_bankvrom(1, vrombase ^ 0x1000, value);
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break;
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case 3:
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mmc_bankvrom(1, vrombase ^ 0x1400, value);
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break;
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case 4:
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mmc_bankvrom(1, vrombase ^ 0x1800, value);
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break;
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case 5:
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mmc_bankvrom(1, vrombase ^ 0x1C00, value);
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break;
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case 6:
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mmc_bankrom(8, (command & 0x40) ? 0xC000 : 0x8000, value);
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break;
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case 7:
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mmc_bankrom(8, 0xA000, value);
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break;
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}
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break;
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case 0xA000:
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/* four screen mirroring crap */
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if (0 == (mmc_getinfo()->flags & ROM_FLAG_FOURSCREEN))
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{
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if (value & 1)
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ppu_mirror(0, 0, 1, 1); /* horizontal */
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else
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ppu_mirror(0, 1, 0, 1); /* vertical */
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}
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break;
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case 0xA001:
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/* Save RAM enable / disable */
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/* Messes up Startropics I/II if implemented -- bah */
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break;
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case 0xC000:
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irq.latch = value;
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// if (irq.reset)
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// irq.counter = irq.latch;
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break;
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case 0xC001:
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irq.reset = true;
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irq.counter = irq.latch;
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break;
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case 0xE000:
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irq.enabled = false;
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// if (irq.reset)
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// irq.counter = irq.latch;
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break;
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case 0xE001:
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irq.enabled = true;
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// if (irq.reset)
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// irq.counter = irq.latch;
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break;
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default:
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break;
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}
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if (true == irq.reset)
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irq.counter = irq.latch;
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}
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static void map4_hblank(int vblank)
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{
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if (vblank)
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return;
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if (ppu_enabled())
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{
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if (irq.counter >= 0)
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{
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irq.reset = false;
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irq.counter--;
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if (irq.counter < 0)
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{
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if (irq.enabled)
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{
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irq.reset = true;
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nes_irq();
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}
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}
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}
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}
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}
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static void map4_getstate(SnssMapperBlock *state)
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{
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state->extraData.mapper4.irqCounter = irq.counter;
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state->extraData.mapper4.irqLatchCounter = irq.latch;
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state->extraData.mapper4.irqCounterEnabled = irq.enabled;
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state->extraData.mapper4.last8000Write = command;
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}
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static void map4_setstate(SnssMapperBlock *state)
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{
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irq.counter = state->extraData.mapper4.irqCounter;
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irq.latch = state->extraData.mapper4.irqLatchCounter;
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irq.enabled = state->extraData.mapper4.irqCounterEnabled;
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command = state->extraData.mapper4.last8000Write;
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}
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static void map4_init(void)
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{
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irq.counter = irq.latch = 0;
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irq.enabled = irq.reset = false;
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reg = command = 0;
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vrombase = 0x0000;
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}
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static const map_memwrite map4_memwrite[] =
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{
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{ 0x8000, 0xFFFF, map4_write },
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{ -1, -1, NULL }
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};
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const mapintf_t map4_intf =
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{
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4, /* mapper number */
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"MMC3", /* mapper name */
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map4_init, /* init routine */
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NULL, /* vblank callback */
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map4_hblank, /* hblank callback */
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map4_getstate, /* get state (snss) */
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map4_setstate, /* set state (snss) */
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NULL, /* memory read structure */
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map4_memwrite, /* memory write structure */
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NULL /* external sound device */
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};
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/*
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** $Log: map004.c,v $
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** Revision 1.2 2001/04/27 14:37:11 neil
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** wheeee
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**
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** Revision 1.1 2001/04/27 12:54:40 neil
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** blah
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**
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** Revision 1.1.1.1 2001/04/27 07:03:54 neil
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** initial
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**
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** Revision 1.2 2000/11/26 15:40:49 matt
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** hey, it actually works now
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**
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** Revision 1.1 2000/10/24 12:19:32 matt
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** changed directory structure
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**
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** Revision 1.12 2000/10/23 15:53:27 matt
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** suppressed warnings
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**
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** Revision 1.11 2000/10/22 19:17:46 matt
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** mapper cleanups galore
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**
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** Revision 1.10 2000/10/22 15:03:13 matt
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** simplified mirroring
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**
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** Revision 1.9 2000/10/21 19:33:38 matt
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** many more cleanups
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**
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** Revision 1.8 2000/10/10 13:58:17 matt
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** stroustrup squeezing his way in the door
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**
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** Revision 1.7 2000/10/08 18:05:44 matt
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** kept old version around, just in case....
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**
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** Revision 1.6 2000/07/15 23:52:19 matt
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** rounded out a bunch more mapper interfaces
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**
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** Revision 1.5 2000/07/10 13:51:25 matt
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** using generic nes_irq() routine now
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**
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** Revision 1.4 2000/07/10 05:29:03 matt
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** cleaned up some mirroring issues
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**
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** Revision 1.3 2000/07/06 02:48:43 matt
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** clearly labelled structure members
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**
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** Revision 1.2 2000/07/05 05:04:39 matt
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** minor modifications
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**
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** Revision 1.1 2000/07/04 23:11:45 matt
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** initial revision
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**
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*/
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