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#include <stdio.h>
#include "atari.h"
#include "cpu.h"
#include "pia.h"
#include "platform.h"
#include "sio.h"
#include "log.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 = 0;
int selftest_enabled = 0;
int Ram256 = 0;
extern int mach_xlxe;
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[278528]; /* 16384 (for RAM under BankRAM buffer) + 65536 (for 130XE) * 4 (for Atari320) */
static UBYTE PORTA_mask = 0xff;
static UBYTE PORTB_mask = 0xff;
void PIA_Initialise(int *argc, char *argv[])
{
PORTA = 0x00;
PORTB = 0xff;
}
UBYTE PIA_GetByte(UWORD addr)
{
UBYTE byte = 0xff;
addr &= 0xff03; /* HW registers are mirrored */
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:
if (!(PACTL & 0x04))
byte = ~PORTA_mask;
else
byte = Atari_PORT(0) & (PORTA_mask|PORTA);
break;
case _PORTB:
switch (machine) {
case Atari:
byte = Atari_PORT(1);
byte &= PORTB_mask|PORTB;
break;
case AtariXL:
case AtariXE:
case Atari320XE:
byte = (PORTB & (~PORTB_mask)) | PORTB_mask;
break;
default:
Aprint("Fatal Error in pia.c: PIA_GetByte(): Unknown machine\n");
Atari800_Exit(FALSE);
#ifndef WIN32
exit(1);
#endif
break;
}
break;
}
return byte;
}
int PIA_PutByte(UWORD addr, UBYTE byte)
{
addr &= 0xff03; /* HW registers are mirrored */
switch (addr) {
case _PACTL:
PACTL = byte;
break;
case _PBCTL:
/* This code is part of the serial I/O emulation */
if ((PBCTL ^ byte) & 0x08) { /* The command line status has changed */
SwitchCommandFrame((byte & 0x08) ? (0) : (1));
}
PBCTL = byte;
#ifdef DEBUG1
printf("WR: PBCTL = %x, PC = %x\n", PBCTL, PC);
#endif
break;
case _PORTA:
if (!(PACTL & 0x04))
PORTA_mask = ~byte;
else
PORTA = byte; /* change from thor */
break;
case _PORTB:
if (!(PBCTL & 0x04)) { /* change from thor */
PORTB_mask = ~byte;
byte = PORTB;
break;
}
if (((byte | PORTB_mask) == 0) && mach_xlxe)
break; /* special hack for old Atari800 games like is Tapper, for example */
switch (machine) {
case Atari:
/*
if (!(PBCTL & 0x04))
PORTB_mask = ~byte;
*/
PORTB = byte;
break;
case AtariXE:
case Atari320XE:
{
int bank;
/* bank = 0 ...normal RAM */
/* bank = 1..4 (..16) ...extended RAM */
if (byte & 0x10) {
/* CPU to normal RAM */
bank = 0;
}
else {
/* CPU to extended RAM */
if (machine == Atari320XE) {
if (Ram256 == 1)
bank = (((byte & 0x0c) | ((byte & 0x60) >> 1)) >> 2) + 1; /* RAMBO */
else
bank = (((byte & 0x0c) | ((byte & 0xc0) >> 2)) >> 2) + 1; /* COMPY SHOP */
}
else
bank = ((byte & 0x0c) >> 2) + 1;
}
if (bank != xe_bank) {
if (selftest_enabled) {
/* SelfTestROM Disable */
memcpy(memory + 0x5000, under_atarixl_os + 0x1000, 0x800);
SetRAM(0x5000, 0x57ff);
selftest_enabled = FALSE;
}
memcpy(atarixe_memory + (((long) xe_bank) << 14), memory + 0x4000, 16384);
memcpy(memory + 0x4000, atarixe_memory + (((long) bank) << 14), 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 ^ byte) & 0x01) { /* Only when is changed this bit !RS! */
if (byte & 0x01) {
/* OS ROM Enable */
memcpy(under_atarixl_os, memory + 0xc000, 0x1000);
memcpy(under_atarixl_os + 0x1800, memory + 0xd800, 0x2800);
memcpy(memory + 0xc000, atarixl_os, 0x1000);
memcpy(memory + 0xd800, atarixl_os + 0x1800, 0x2800);
SetROM(0xc000, 0xcfff);
SetROM(0xd800, 0xffff);
}
else {
/* OS ROM Disable */
memcpy(memory + 0xc000, under_atarixl_os, 0x1000);
memcpy(memory + 0xd800, under_atarixl_os + 0x1800, 0x2800);
SetRAM(0xc000, 0xcfff);
SetRAM(0xd800, 0xffff);
}
}
/*
=====================================
Enable/Disable BASIC ROM
An Atari XL/XE can only disable Basic
Other cartridge cannot be disable
=====================================
*/
if (!rom_inserted) {
if ((PORTB ^ byte) & 0x02) { /* Only when change this bit !RS! */
if (byte & 0x02) {
/* BASIC Disable */
memcpy(memory + 0xa000, under_atari_basic, 0x2000);
SetRAM(0xa000, 0xbfff);
}
else {
/* BASIC Enable */
memcpy(under_atari_basic, memory + 0xa000, 0x2000);
memcpy(memory + 0xa000, atari_basic, 0x2000);
SetROM(0xa000, 0xbfff);
}
}
}
/*
* Enable/Disable Self Test ROM
*/
if (byte & 0x80) {
/* SelfTestROM Disable */
if (selftest_enabled) {
memcpy(memory + 0x5000, under_atarixl_os + 0x1000, 0x800);
SetRAM(0x5000, 0x57ff);
selftest_enabled = FALSE;
}
}
else {
/* SELFTEST ROM enable */
if (!selftest_enabled && ((byte & 0x10) || (Ram256 < 2))) {
/* Only when CPU access to normal RAM or isn't 256Kb RAM or RAMBO mode is set */
memcpy(under_atarixl_os + 0x1000, memory + 0x5000, 0x800);
memcpy(memory + 0x5000, atarixl_os + 0x1000, 0x800);
SetROM(0x5000, 0x57ff);
selftest_enabled = TRUE;
}
}
PORTB = byte;
break;
default:
Aprint("Fatal Error in pia.c: PIA_PutByte(): Unknown machine\n");
Atari800_Exit(FALSE);
#ifndef WIN32
exit(1);
#endif
break;
}
break;
}
return FALSE;
}
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