187 lines
3.8 KiB
C
187 lines
3.8 KiB
C
/************************************************************************
|
|
|
|
PCem: IBM 5150 Cassette support
|
|
|
|
Copyright (C) 2019 John Elliott <seasip.webmaster@gmail.com>
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
|
|
*************************************************************************/
|
|
|
|
#include <stdlib.h>
|
|
#include "ibm.h"
|
|
#include "cpu.h"
|
|
#include "x86.h"
|
|
#include "device.h"
|
|
#include "pzx.h"
|
|
|
|
char cassettefn[256];
|
|
|
|
typedef struct cassette_t
|
|
{
|
|
uint8_t motor; /* Motor status */
|
|
pzxfile_t pzx;
|
|
int cycles_last; /* Cycle count at last cassette poll */
|
|
|
|
} cassette_t;
|
|
|
|
extern device_t cassette_device;
|
|
|
|
|
|
static cassette_t *st_cas;
|
|
|
|
|
|
|
|
#define CAS_LOG(x) pclog x
|
|
// #define CAS_LOG(x)
|
|
|
|
|
|
/* The PCem CPU uses IBM cycles (4.77MHz). PZX uses Spectrum cycles (3.5MHz)
|
|
* so scale accordingly. */
|
|
static int32_t pzx_cycles(int32_t pc)
|
|
{
|
|
double d = pc;
|
|
|
|
return (int32_t)(((d * 3.5) / 4.772728) + 0.5);
|
|
}
|
|
|
|
void cassette_eject(void)
|
|
{
|
|
if (st_cas->pzx.input)
|
|
{
|
|
pzx_close(&st_cas->pzx);
|
|
}
|
|
cassettefn[0] = 0;
|
|
}
|
|
|
|
void cassette_load(const char *filename)
|
|
{
|
|
FILE *fp;
|
|
unsigned char magic[8];
|
|
|
|
if (!filename) return;
|
|
|
|
fp = fopen(filename, "rb");
|
|
if (!fp)
|
|
{
|
|
/* Warn user? */
|
|
CAS_LOG(("Failed to open cassette input %s\n", filename));
|
|
return;
|
|
}
|
|
memset(magic, 0, sizeof(magic));
|
|
fread(magic, 1, sizeof(magic), fp);
|
|
|
|
/* Check for PZX signature. In due course support could be added for
|
|
* other formats like TZX */
|
|
if (!memcmp(magic, "PZXT", 4))
|
|
{
|
|
const char *result;
|
|
|
|
result = pzx_open(&st_cas->pzx, fp);
|
|
|
|
if (result)
|
|
{
|
|
CAS_LOG(("Failed to open %s as PZX: %s\n",
|
|
filename, result));
|
|
fclose(fp);
|
|
return;
|
|
}
|
|
strcpy(cassettefn, filename);
|
|
}
|
|
}
|
|
|
|
|
|
uint8_t cassette_input(void)
|
|
{
|
|
int ticks;
|
|
|
|
/* While motor is off, result is loopback */
|
|
if (!st_cas->motor)
|
|
{
|
|
return ppispeakon;
|
|
}
|
|
/* If there is no tapefile open don't try to extract data */
|
|
if (st_cas->pzx.input == NULL) return 0;
|
|
/* Otherwise see how many ticks there have been since the last input */
|
|
if (st_cas->cycles_last == -1)
|
|
{
|
|
st_cas->cycles_last = cycles;
|
|
}
|
|
if (cycles <= st_cas->cycles_last)
|
|
{
|
|
ticks = (st_cas->cycles_last - cycles);
|
|
}
|
|
else
|
|
{
|
|
ticks = (st_cas->cycles_last + (cpu_get_speed() / 100) - cycles);
|
|
}
|
|
st_cas->cycles_last = cycles;
|
|
|
|
return pzx_advance(&st_cas->pzx, pzx_cycles(ticks));
|
|
}
|
|
|
|
|
|
|
|
void cassette_set_motor(uint8_t on)
|
|
{
|
|
if (on && !st_cas->motor)
|
|
{
|
|
CAS_LOG(("Start cassette motor\n"));
|
|
st_cas->cycles_last = -1;
|
|
}
|
|
if (st_cas->motor && !on)
|
|
{
|
|
CAS_LOG(("Stop cassette motor\n"));
|
|
st_cas->cycles_last = -1;
|
|
}
|
|
st_cas->motor = on;
|
|
}
|
|
|
|
|
|
static void *cassette_init(void)
|
|
{
|
|
cassette_t *cas = malloc(sizeof(cassette_t));
|
|
|
|
memset(cas, 0, sizeof(cassette_t));
|
|
pzx_init(&cas->pzx);
|
|
|
|
st_cas = cas;
|
|
return cas;
|
|
}
|
|
|
|
|
|
static void cassette_close(void *p)
|
|
{
|
|
cassette_t *cas = (cassette_t *)p;
|
|
|
|
pzx_close(&cas->pzx);
|
|
|
|
free(cas);
|
|
}
|
|
|
|
|
|
device_t cassette_device =
|
|
{
|
|
"Cassette",
|
|
0,
|
|
cassette_init,
|
|
cassette_close,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL
|
|
};
|
|
|