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#include <stdio.h>
#include "atari.h"
#include "cpu.h"
#include "pia.h"
#include "platform.h"
#define FALSE 0
#define TRUE 1
static char *rcsid = "$Id: pia.c,v 1.12 1998/02/21 14:55:43 david Exp $";
UBYTE PACTL;
UBYTE PBCTL;
UBYTE PORTA;
UBYTE PORTB;
int xe_bank = -1;
int rom_inserted;
UBYTE atari_basic[8192];
UBYTE atarixl_os[16384];
static UBYTE under_atari_basic[8192];
static UBYTE under_atarixl_os[16384];
static UBYTE atarixe_memory[65536];
static UBYTE atarixe_16kbuffer[16384];
static UBYTE PORTA_mask = 0xff;
static UBYTE PORTB_mask = 0xff;
void PIA_Initialise(int *argc, char *argv[])
{
PORTA = 0xff;
PORTB = 0xff;
}
UBYTE PIA_GetByte(UWORD addr)
{
UBYTE byte;
if (machine == Atari)
addr &= 0xff03;
switch (addr) {
case _PACTL:
byte = PACTL;
break;
case _PBCTL:
byte = PBCTL;
#ifdef DEBUG1
printf("RD: PBCTL = %x, PC = %x\n", PBCTL, PC);
#endif
break;
case _PORTA:
byte = Atari_PORT(0);
byte &= PORTA_mask;
break;
case _PORTB:
switch (machine) {
case Atari:
byte = Atari_PORT(1);
byte &= PORTB_mask;
break;
case AtariXL:
case AtariXE:
byte = PORTB;
break;
default:
printf("Fatal Error in pia.c: PIA_GetByte(): Unknown machine\n");
Atari800_Exit(FALSE);
exit(1);
break;
}
break;
}
return byte;
}
int PIA_PutByte(UWORD addr, UBYTE byte)
{
if (machine == Atari)
addr &= 0xff03;
switch (addr) {
case _PACTL:
PACTL = byte;
break;
case _PBCTL:
PBCTL = byte;
#ifdef DEBUG1
printf("WR: PBCTL = %x, PC = %x\n", PBCTL, PC);
#endif
break;
case _PORTA:
if (!(PACTL & 0x04))
PORTA_mask = ~byte;
break;
case _PORTB:
if ((byte == 0) && (machine == AtariXL || machine == AtariXE))
break; /* special hack for old Atari800 games like is Tapper, for example */
switch (machine) {
case Atari:
if (!(PBCTL & 0x04))
PORTB_mask = ~byte;
break;
case AtariXE:
{
int cpu_flag = (byte & 0x10);
#ifdef DEBUG
int antic_flag = (byte & 0x20);
#endif
int bank = (byte & 0x0c) >> 2;
#ifdef DEBUG
printf("CPU = %d, ANTIC = %d, XE BANK = %d\n",
cpu_flag, antic_flag, bank);
#endif
/*
* Possible Bank Transitions
*
* Main -> Main
* Main -> Bank1,2,3,4
* Bank1,2,3,4 -> Main
* Bank1,2,3,4 -> Bank1,2,3,4
*/
if (cpu_flag) {
if (xe_bank != -1) {
memcpy(&atarixe_memory[xe_bank * 16384],
&memory[0x4000],
16384);
memcpy(&memory[0x4000], atarixe_16kbuffer, 16384);
xe_bank = -1;
}
}
else if (bank != xe_bank) {
if (xe_bank == -1) {
memcpy(atarixe_16kbuffer,
&memory[0x4000],
16384);
}
else {
memcpy(&atarixe_memory[xe_bank * 16384],
&memory[0x4000],
16384);
}
memcpy(&memory[0x4000],
&atarixe_memory[bank * 16384],
16384);
xe_bank = bank;
}
}
case AtariXL:
#ifdef DEBUG
printf("Storing %x to PORTB, PC = %x\n", byte, regPC);
#endif
/*
* Enable/Disable OS ROM 0xc000-0xcfff and 0xd800-0xffff
*/
if (!(PORTB & 0x01)) {
memcpy(under_atarixl_os, memory + 0xc000, 0x1000);
memcpy(under_atarixl_os + 0x1800, memory + 0xd800, 0x2800);
}
if (byte & 0x01) {
#ifdef DEBUG
printf("OS ROM Enabled\n");
#endif
memcpy(memory + 0xc000, atarixl_os, 0x1000);
memcpy(memory + 0xd800, atarixl_os + 0x1800, 0x2800);
SetROM(0xc000, 0xcfff);
SetROM(0xd800, 0xffff);
}
else {
#ifdef DEBUG
printf("OS ROM Disabled\n");
#endif
memcpy(memory + 0xc000, under_atarixl_os, 0x1000);
memcpy(memory + 0xd800, under_atarixl_os + 0x1800, 0x2800);
SetRAM(0xc000, 0xcfff);
SetRAM(0xd800, 0xffff);
}
/*
=====================================
An Atari XL/XE can only disable Basic
Other cartridge cannot be disable
=====================================
*/
if (!rom_inserted) {
/*
* If RAM is currently enabled between 0xa000 and
* 0xbfff then under_atari_basic is updated
*/
if (PORTB & 0x02) {
memcpy(under_atari_basic, memory + 0xa000, 0x2000);
}
/*
* Enable/Disable BASIC ROM
*/
if (byte & 0x02) {
#ifdef DEBUG
printf("BASIC disabled\n");
#endif
memcpy(memory + 0xa000, under_atari_basic, 0x2000);
SetRAM(0xa000, 0xbfff);
}
else {
#ifdef DEBUG
printf("BASIC enabled\n");
#endif
memcpy(memory + 0xa000, atari_basic, 0x2000);
SetROM(0xa000, 0xbfff);
}
}
/*
* Enable/Disable Self Test ROM
*/
if (PORTB & 0x80) {
memcpy(under_atarixl_os + 0x1000, memory + 0x5000, 0x800);
}
if (byte & 0x80) {
#ifdef DEBUG
printf("Self Test ROM Disabled\n");
#endif
memcpy(memory + 0x5000, under_atarixl_os + 0x1000, 0x800);
SetRAM(0x5000, 0x57ff);
}
else {
#ifdef DEBUG
printf("Self Test ROM Enabled\n");
#endif
memcpy(memory + 0x5000, atarixl_os + 0x1000, 0x800);
SetROM(0x5000, 0x57ff);
}
PORTB = byte;
break;
default:
printf("Fatal Error in pia.c: PIA_PutByte(): Unknown machine\n");
Atari800_Exit(FALSE);
exit(1);
break;
}
break;
}
return FALSE;
}
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