Intel-Systems/common/isbc80-20.c

/*  iSBC80-20.c: Intel iSBC 80/20 Processor simulator

    Copyright (c) 2010, William A. Beech

        Permission is hereby granted, free of charge, to any person obtaining a
        copy of this software and associated documentation files (the "Software"),
        to deal in the Software without restriction, including without limitation
        the rights to use, copy, modify, merge, publish, distribute, sublicense,
        and/or sell copies of the Software, and to permit persons to whom the
        Software is furnished to do so, subject to the following conditions:

        The above copyright notice and this permission notice shall be included in
        all copies or substantial portions of the Software.

        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
        WILLIAM A. BEECH BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
        IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
        CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

        Except as contained in this notice, the name of William A. Beech shall not be
        used in advertising or otherwise to promote the sale, use or other dealings
        in this Software without prior written authorization from William A. Beech.

    NOTES:

        This software was written by Bill Beech, Dec 2010, to allow emulation of Multibus
        Computer Systems.
*/

#include "system_defs.h"

/* set the base I/O address for the 8259 */
#define I8259_BASE      0xD8

/* set the base I/O address for the first 8255 */
#define I8255_BASE_0    0xE4

/* set the base I/O address for the second 8255 */
#define I8255_BASE_1    0xE8

/* set the base I/O address for the 8251 */
#define I8251_BASE      0xEC

/* set the base and size for the EPROM on the iSBC 80/20 */
#define ROM_SIZE        0x1000

/* set the base and size for the RAM on the iSBC 80/20 */
#define RAM_BASE        0x3C00
#define RAM_SIZE        0x0400 

/* set INTR for CPU */
#define INTR            INT_1

/* function prototypes */

int32 get_mbyte(int32 addr);
int32 get_mword(int32 addr);
void put_mbyte(int32 addr, int32 val);
void put_mword(int32 addr, int32 val);
t_stat i80_10_reset (DEVICE *dptr);

/* external function prototypes */

extern t_stat i8080_reset (DEVICE *dptr);   /* reset the 8080 emulator */
extern int32 multibus_get_mbyte(int32 addr);
extern void  multibus_put_mbyte(int32 addr, int32 val);
extern int32 EPROM_get_mbyte(int32 addr);
extern int32 RAM_get_mbyte(int32 addr);
extern void RAM_put_mbyte(int32 addr, int32 val);
extern UNIT i8255_unit;
extern UNIT EPROM_unit;
extern UNIT RAM_unit;
extern t_stat i8251_reset (DEVICE *dptr, int32 base);
extern t_stat i8255_reset (DEVICE *dptr, int32 base);
extern t_stat i8259_reset (DEVICE *dptr, int32 base);
extern t_stat pata_reset (DEVICE *dptr, int32 base);
extern t_stat EPROM_reset (DEVICE *dptr, int32 size);
extern t_stat RAM_reset (DEVICE *dptr, int32 base, int32 size);

/*  CPU reset routine 
    put here to cause a reset of the entire iSBC system */

t_stat SBC_reset (DEVICE *dptr)
{    
    sim_printf("Initializing iSBC-80/20\n");
    i8080_reset(NULL);
    i8259_reset(NULL, I8259_BASE);
    i8255_reset(NULL, I8255_BASE_0);
    i8255_reset(NULL, I8255_BASE_1);
    i8251_reset(NULL, I8251_BASE);
    EPROM_reset(NULL, ROM_SIZE);
    RAM_reset(NULL, RAM_BASE, RAM_SIZE);
    return SCPE_OK;
}

/*  get a byte from memory - handle RAM, ROM and Multibus memory */

int32 get_mbyte(int32 addr)
{
    int32 val, org, len;

    /* if local EPROM handle it */
    if ((i8255_unit.u5 & 0x01) &&       /* EPROM enabled? */
        (addr >= EPROM_unit.u3) && (addr < (EPROM_unit.u3 + EPROM_unit.capac))) {
        return EPROM_get_mbyte(addr);
    } /* if local RAM handle it */
    if ((i8255_unit.u5 & 0x02) &&       /* local RAM enabled? */
        (addr >= RAM_unit.u3) && (addr < (RAM_unit.u3 + RAM_unit.capac))) {
        return RAM_get_mbyte(addr);
    } /* otherwise, try the multibus */
    return multibus_get_mbyte(addr);
}

/*  get a word from memory */

int32 get_mword(int32 addr)
{
    int32 val;

    val = get_mbyte(addr);
    val |= (get_mbyte(addr+1) << 8);
    return val;
}

/*  put a byte to memory - handle RAM, ROM and Multibus memory */

void put_mbyte(int32 addr, int32 val)
{
    /* if local EPROM handle it */
    if ((i8255_unit.u5 & 0x01) &&       /* EPROM enabled? */ 
        (addr >= EPROM_unit.u3) && (addr <= (EPROM_unit.u3 + EPROM_unit.capac))) {
        sim_printf("Write to R/O memory address %04X - ignored\n", addr);
        return;
    } /* if local RAM handle it */
    if ((i8255_unit.u5 & 0x02) &&       /* local RAM enabled? */ 
        (addr >= RAM_unit.u3) && (addr <= (RAM_unit.u3 + RAM_unit.capac))) {
        RAM_put_mbyte(addr, val);
        return;
    } /* otherwise, try the multibus */
    multibus_put_mbyte(addr, val);
}

/*  put a word to memory */

void put_mword(int32 addr, int32 val)
{
    put_mbyte(addr, val);
    put_mbyte(addr+1, val >> 8);
}

/* end of iSBC80-20.c */