mirror of
https://github.com/AppleWin/AppleWin.git
synced 2024-08-30 22:29:36 +00:00
273 lines
7.3 KiB
C++
273 lines
7.3 KiB
C++
/*
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* mc6821.c - MC6821 emulation for the 1571 disk drives with DD3.
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*
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* Written by
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* Andreas Boose <viceteam@t-online.de>
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*
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* This file is part of VICE, the Versatile Commodore Emulator.
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* See README for copyright notice.
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*
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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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*
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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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*
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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
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* 02111-1307 USA.
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*
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*/
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/*#define MC_DEBUG*/
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#include "StdAfx.h"
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#include "6821.h"
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#define PIA_W_CALLBACK(st, val) \
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if ( st.func ) st.func( st.objTo, val )
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/*-----------------------------------------------------------------------*/
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/* MC6821 register functions. */
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void C6821::mc6821_write_pra(BYTE byte, unsigned int dnr)
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{
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//if (mc6821[dnr].drive->parallel_cable == DRIVE_PC_DD3)
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// parallel_cable_drive_write(byte, PARALLEL_WRITE, dnr);
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mc6821[dnr].pra = byte;
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if (mc6821[dnr].ddra) // AppleWin:TC
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PIA_W_CALLBACK( m_stOutA, mc6821[dnr].pra & mc6821[dnr].ddra );
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}
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void C6821::mc6821_write_ddra(BYTE byte, unsigned int dnr)
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{
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//parallel_cable_drive_write((BYTE)((~byte) | mc6821[dnr].pra), PARALLEL_WRITE, dnr);
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if (mc6821[dnr].ddra == byte) // AppleWin:TC
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return;
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mc6821[dnr].ddra = byte;
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if (mc6821[dnr].ddra) // AppleWin:TC
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PIA_W_CALLBACK( m_stOutA, mc6821[dnr].pra & mc6821[dnr].ddra );
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}
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BYTE C6821::mc6821_read_pra(unsigned int dnr)
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{
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BYTE byte = m_byIA; // AppleWin:TC
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//BYTE byte = 0xff;
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//int hs = 0;
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//if ((mc6821[dnr].cra & 0x28) == 0x28)
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// hs = 1;
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//if (mc6821[dnr].drive->parallel_cable == DRIVE_PC_DD3)
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// byte = parallel_cable_drive_read(hs);
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mc6821[dnr].cra = (BYTE)(mc6821[dnr].cra & 0x7f);
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mc6821[dnr].cra = (BYTE)(mc6821[dnr].cra & 0xbf); // AppleWin:TC (Clear IRQ2)
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return (mc6821[dnr].pra & mc6821[dnr].ddra)
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| (byte & ~(mc6821[dnr].ddra));
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}
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void C6821::mc6821_write_prb(BYTE byte, unsigned int dnr)
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{
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mc6821[dnr].prb = byte;
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if (mc6821[dnr].ddrb) // AppleWin:TC
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PIA_W_CALLBACK( m_stOutB, mc6821[dnr].prb & mc6821[dnr].ddrb );
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}
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void C6821::mc6821_write_ddrb(BYTE byte, unsigned int dnr)
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{
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if (mc6821[dnr].ddrb == byte) // AppleWin:TC
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return;
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mc6821[dnr].ddrb = byte;
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if (mc6821[dnr].ddrb) // AppleWin:TC
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PIA_W_CALLBACK( m_stOutB, mc6821[dnr].prb & mc6821[dnr].ddrb );
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}
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BYTE C6821::mc6821_read_prb(unsigned int dnr)
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{
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mc6821[dnr].crb = (BYTE)(mc6821[dnr].crb & 0x7f); // AppleWin:TC (Clear IRQ1)
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mc6821[dnr].crb = (BYTE)(mc6821[dnr].crb & 0xbf); // AppleWin:TC (Clear IRQ2)
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BYTE byte = m_byIB; // AppleWin:TC
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return (mc6821[dnr].prb & mc6821[dnr].ddrb)
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| (byte & ~(mc6821[dnr].ddrb));
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}
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void C6821::mc6821_write_cra(BYTE byte, unsigned int dnr)
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{
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// static BYTE old_cra = 0;
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//
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// if ((old_cra & 0x38) != (byte & 0x38)) {
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//#ifdef MC_DEBUG
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// log_debug("MODE %02x", byte & 0x38);
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//#endif
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// old_cra = byte;
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// }
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mc6821[dnr].cra = byte;
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}
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void C6821::mc6821_write_crb(BYTE byte, unsigned int dnr)
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{
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mc6821[dnr].crb = byte;
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}
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/*-----------------------------------------------------------------------*/
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/* MC6821 signals. */
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void C6821::mc6821_set_signal(/*drive_context_t *drive_context,*/ int line)
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{
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unsigned int dnr = 0;
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// dnr = drive_context->mynumber;
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switch (line) {
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case MC6821_SIG_CA1:
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mc6821[dnr].cra = (BYTE)(mc6821[dnr].cra | 0x80);
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break;
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case MC6821_SIG_CA2:
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mc6821[dnr].cra = (BYTE)(mc6821[dnr].cra | 0x40);
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break;
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case MC6821_SIG_CB1:
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mc6821[dnr].crb = (BYTE)(mc6821[dnr].crb | 0x80);
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break;
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case MC6821_SIG_CB2:
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mc6821[dnr].crb = (BYTE)(mc6821[dnr].crb | 0x40);
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break;
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}
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}
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/*-----------------------------------------------------------------------*/
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/* MC6821 register read/write access. */
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void C6821::mc6821_store_internal(WORD addr, BYTE byte, unsigned int dnr)
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{
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#ifdef MC_DEBUG
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log_debug("MC WRITE ADDR: %i DATA:%02x CLK:%i",
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addr, byte, drive_clk[dnr]);
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#endif
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switch (addr) {
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case 0: // PIA_DDRA
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if (mc6821[dnr].cra & 0x04)
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mc6821_write_pra(byte, dnr);
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else
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mc6821_write_ddra(byte, dnr);
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break;
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case 1: // PIA_CTLA
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mc6821_write_cra(byte, dnr);
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break;
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case 2: // PIA_DDRB
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if (mc6821[dnr].crb & 0x04)
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mc6821_write_prb(byte, dnr);
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else
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mc6821_write_ddrb(byte, dnr);
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break;
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case 3: // PIA_CTLB
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mc6821_write_crb(byte, dnr);
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break;
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}
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}
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BYTE C6821::mc6821_read_internal(WORD addr, unsigned int dnr)
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{
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BYTE tmp = 0;
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switch (addr) {
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case 0: // PIA_DDRA
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if (mc6821[dnr].cra & 0x04)
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tmp = mc6821_read_pra(dnr);
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else
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tmp = mc6821[dnr].ddra;
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break;
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case 1: // PIA_CTLA
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tmp = mc6821[dnr].cra;
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break;
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case 2: // PIA_DDRB
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if (mc6821[dnr].crb & 0x04)
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tmp = mc6821_read_prb(dnr);
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else
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tmp = mc6821[dnr].ddrb;
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break;
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case 3: // PIA_CTLB
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tmp = mc6821[dnr].crb;
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break;
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}
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#ifdef MC_DEBUG
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log_debug("MC READ ADDR: %i DATA:%02x CLK:%i",
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addr, tmp, drive_clk[dnr]);
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#endif
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return tmp;
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}
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void C6821::mc6821_reset_internal(unsigned int dnr)
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{
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mc6821[dnr].pra = 0;
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mc6821[dnr].ddra = 0;
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mc6821[dnr].cra = 0;
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mc6821[dnr].prb = 0;
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mc6821[dnr].ddrb = 0;
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mc6821[dnr].crb = 0;
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}
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/*-----------------------------------------------------------------------*/
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//static void REGPARM3 mc6821_store(drive_context_t *drv, WORD addr, BYTE byte)
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//{
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// mc6821_store_internal((WORD)(addr & 3), byte, drv->mynumber);
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//}
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//
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//static BYTE REGPARM2 mc6821_read(drive_context_t *drv, WORD addr)
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//{
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// return mc6821_read_internal((WORD)(addr & 3), drv->mynumber);
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//}
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/*-----------------------------------------------------------------------*/
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/* MC6821 external interface. */
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/* Functions using drive context. */
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void C6821::mc6821_init(/*drive_context_t *drv*/)
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{
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//mc6821[drv->mynumber].drive = drv->drive;
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}
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void C6821::mc6821_reset(/*drive_context_t *drv*/)
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{
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mc6821_reset_internal();
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}
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//void mc6821_mem_init(struct drive_context_s *drv, unsigned int type)
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//{
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// drivecpud_context_t *cpud;
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//
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// cpud = drv->cpud;
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//
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// /* Setup parallel cable */
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// if (type == DRIVE_TYPE_1541 || type == DRIVE_TYPE_1541II
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// || type == DRIVE_TYPE_1570 || type == DRIVE_TYPE_1571
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// || type == DRIVE_TYPE_1571CR) {
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// if (drv->drive->parallel_cable == DRIVE_PC_DD3) {
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// drivemem_set_func(cpud, 0x50, 0x60, mc6821_read, mc6821_store);
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// }
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// }
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//}
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