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libretro-atari800/atari800/src/pbi_bb.c
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/*
* pbi_bb.c - CSS Black Box emulation
*
* Copyright (C) 2007-2008 Perry McFarlane
* Copyright (C) 1998-2008 Atari800 development team (see DOC/CREDITS)
*
* This file is part of the Atari800 emulator project which emulates
* the Atari 400, 800, 800XL, 130XE, and 5200 8-bit computers.
*
* Atari800 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.
*
* Atari800 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 Atari800; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "atari.h"
#include "pbi_bb.h"
#include "util.h"
#include "log.h"
#include "pbi.h"
#include "memory.h"
#include "pia.h"
#include "pokey.h"
#include "cpu.h"
#include "pbi_scsi.h"
#include "statesav.h"
#include "util.h"
#include <stdlib.h>
#ifdef PBI_DEBUG
#define D(a) a
#else
#define D(a) do{}while(0)
#endif
/* CSS Black Box emulation */
/* information source: http://www.mathyvannisselroy.nl/bbdoku.txt*/
#define BB_BUTTON_IRQ_MASK 1
int PBI_BB_enabled = FALSE;
static UBYTE *bb_rom;
static int bb_ram_bank_offset = 0;
static UBYTE *bb_ram;
#define BB_RAM_SIZE 0x10000
static UBYTE bb_rom_bank = 0;
static int bb_rom_size;
static int bb_rom_high_bit = 0x00;/*0x10*/
static char bb_rom_filename[FILENAME_MAX];
static UBYTE bb_PCR = 0; /* VIA Peripheral control register*/
static int bb_scsi_enabled = FALSE;
static char bb_scsi_disk_filename[FILENAME_MAX] = Util_FILENAME_NOT_SET;
static void init_bb(void)
{
FILE *bbfp;
bbfp = fopen(bb_rom_filename,"rb");
bb_rom_size = Util_flen(bbfp);
fclose(bbfp);
if (bb_rom_size != 0x10000 && bb_rom_size != 0x4000) {
Log_print("Invalid black box rom size\n");
return;
}
free(bb_rom);
bb_rom = (UBYTE *)Util_malloc(bb_rom_size);
if (!Atari800_LoadImage(bb_rom_filename, bb_rom, bb_rom_size)) {
free(bb_rom);
bb_rom = NULL;
return;
}
D(printf("loaded black box rom image\n"));
PBI_BB_enabled = TRUE;
if (PBI_SCSI_disk != NULL) fclose(PBI_SCSI_disk);
if (!Util_filenamenotset(bb_scsi_disk_filename)) {
PBI_SCSI_disk = fopen(bb_scsi_disk_filename, "rb+");
if (PBI_SCSI_disk == NULL) {
Log_print("Error opening BB SCSI disk image:%s", bb_scsi_disk_filename);
}
else {
D(printf("Opened BB SCSI disk image\n"));
bb_scsi_enabled = TRUE;
}
}
if (!bb_scsi_enabled) {
PBI_SCSI_BSY = TRUE; /* makes BB give up easier? */
}
free(bb_ram);
bb_ram = (UBYTE *)Util_malloc(BB_RAM_SIZE);
memset(bb_ram,0,BB_RAM_SIZE);
}
int PBI_BB_Initialise(int *argc, char *argv[])
{
int i, j;
for (i = j = 1; i < *argc; i++) {
if (strcmp(argv[i], "-bb") == 0) {
init_bb();
}
else {
if (strcmp(argv[i], "-help") == 0) {
Log_print("\t-bb Emulate the CSS Black Box");
}
argv[j++] = argv[i];
}
}
*argc = j;
return TRUE;
}
void PBI_BB_Exit(void)
{
if (PBI_SCSI_disk != NULL) {
fclose(PBI_SCSI_disk);
PBI_SCSI_disk = NULL;
}
free(bb_ram);
free(bb_rom);
bb_rom = bb_ram = NULL;
}
int PBI_BB_ReadConfig(char *string, char *ptr)
{
if (strcmp(string, "BLACK_BOX_ROM") == 0)
Util_strlcpy(bb_rom_filename, ptr, sizeof(bb_rom_filename));
else if (strcmp(string, "BB_SCSI_DISK") == 0)
Util_strlcpy(bb_scsi_disk_filename, ptr, sizeof(bb_scsi_disk_filename));
else return FALSE; /* no match */
return TRUE; /* matched something */
}
void PBI_BB_WriteConfig(FILE *fp)
{
fprintf(fp, "BLACK_BOX_ROM=%s\n", bb_rom_filename);
if (!Util_filenamenotset(bb_scsi_disk_filename)) {
fprintf(fp, "BB_SCSI_DISK=%s\n", bb_scsi_disk_filename);
}
}
UBYTE PBI_BB_D1GetByte(UWORD addr, int no_side_effects)
{
UBYTE result = 0x00;/*ff;*/
if (addr == 0xd1be) result = 0xff;
else if (addr == 0xd170) {
/* status */
result = ((!(PBI_SCSI_REQ))<<7)|((!PBI_SCSI_BSY)<<6)|((!PBI_SCSI_SEL)<<2)|((!PBI_SCSI_CD)<<1)|(!PBI_SCSI_IO);
}
else if (addr == 0xd171) {
if (bb_scsi_enabled) {
result = PBI_SCSI_GetByte();
if (!no_side_effects && ((bb_PCR & 0x0e)>>1) == 0x04) {
/* handshake output */
PBI_SCSI_PutACK(1);
PBI_SCSI_PutACK(0);
}
}
}
else if (addr == 0xd1bc) result = (bb_ram_bank_offset >> 8);/*RAMPAGE*/
else if (addr == 0xd1be) {
/* SWITCH */
result = 0x02;
}
else if (addr == 0xd1ff) result = PBI_IRQ ? (0x08 | 0x02) : 0 ;
D(if (addr!=0xd1ff) printf("BB Read:%4x PC:%4x byte=%2x\n", addr, CPU_remember_PC[(CPU_remember_PC_curpos-1)%CPU_REMEMBER_PC_STEPS], result));
return result;
}
void PBI_BB_D1PutByte(UWORD addr, UBYTE byte)
{
D(printf("BB Write addr:%4x byte:%2x, cpu:%4x\n", addr, byte, CPU_remember_PC[(CPU_remember_PC_curpos-1)%CPU_REMEMBER_PC_STEPS]));
if (addr == 0xd170) {
if (bb_scsi_enabled) PBI_SCSI_PutSEL(!(byte&0x04));
}
else if (addr == 0xd171) {
if (bb_scsi_enabled) {
PBI_SCSI_PutByte(byte);
if (((bb_PCR & 0x0e)>>1) == 0x04) {
/* handshake output */
PBI_SCSI_PutACK(1);
PBI_SCSI_PutACK(0);
}
}
}
else if (addr == 0xd17c) { /* PCR */
bb_PCR = byte;
if (((bb_PCR & 0x0e)>>1) == 0x06) {
/* low output */
if (bb_scsi_enabled) PBI_SCSI_PutACK(1);
}
else if (((bb_PCR & 0x0e)>>1) == 0x07) {
/* high output */
if (bb_scsi_enabled) PBI_SCSI_PutACK(0);
}
}
else if (addr == 0xd1bc) {
/* RAMPAGE */
/* Copy old page to buffer, Copy new page from buffer */
memcpy(bb_ram+bb_ram_bank_offset,MEMORY_mem + 0xd600,0x100);
bb_ram_bank_offset = (byte << 8);
memcpy(MEMORY_mem + 0xd600, bb_ram+bb_ram_bank_offset, 0x100);
}
else if (addr == 0xd1be) {
/* high rom bit */
if (bb_rom_high_bit != ((byte & 0x04) << 2) && bb_rom_size == 0x10000) {
/* high bit has changed */
bb_rom_high_bit = ((byte & 0x04) << 2);
if (bb_rom_bank > 0 && bb_rom_bank < 8) {
memcpy(MEMORY_mem + 0xd800, bb_rom + (bb_rom_bank + bb_rom_high_bit)*0x800, 0x800);
D(printf("black box bank:%2x activated\n", bb_rom_bank+bb_rom_high_bit));
}
}
}
else if ((addr & 0xffc0) == 0xd1c0) {
/* byte &= 0x0f; */
if (bb_rom_bank != byte) {
/* PDVS (d1ff) rom bank */
int offset = -1;
if (bb_rom_size == 0x4000) {
if (byte >= 8 && byte <= 0x0f) offset = (byte - 8)*0x800;
else if (byte > 0 && byte < 0x08) offset = byte*0x800;
}
else { /* bb_rom_size == 0x10000 */
if (byte > 0 && byte < 0x10) offset = (byte + bb_rom_high_bit)*0x800;
}
if (offset != -1) {
memcpy(MEMORY_mem + 0xd800, bb_rom + offset, 0x800);
D(printf("black box bank:%2x activated\n", byte + bb_rom_high_bit));
}
else {
memcpy(MEMORY_mem + 0xd800, MEMORY_os + 0x1800, 0x800);
if (byte != 0) D(printf("d1ff ERROR: byte=%2x\n", byte));
D(printf("Floating point rom activated\n"));
}
bb_rom_bank = byte;
}
}
}
/* Black Box RAM page at D600-D6ff*/
/* Possible to put code in this ram, so we can't avoid using MEMORY_mem[]
* because opcode fetch doesn't call this function*/
UBYTE PBI_BB_D6GetByte(UWORD addr, int no_side_effects)
{
return MEMORY_mem[addr];
}
/* $D6xx */
void PBI_BB_D6PutByte(UWORD addr, UBYTE byte)
{
MEMORY_mem[addr]=byte;
}
static int buttondown;
void PBI_BB_Menu(void)
{
if (!PBI_BB_enabled) return;
if (buttondown == FALSE) {
D(printf("blackbox button down interrupt generated\n"));
CPU_GenerateIRQ();
PBI_IRQ |= BB_BUTTON_IRQ_MASK;
buttondown = TRUE;
}
}
void PBI_BB_Frame(void)
{
static int count = 0;
if (buttondown) {
if (count < 1) count++;
else {
D(printf("blackbox button up\n"));
PBI_IRQ &= ~BB_BUTTON_IRQ_MASK;
/* update pokey IRQ status */
POKEY_PutByte(POKEY_OFFSET_IRQEN, POKEY_IRQEN);
buttondown = FALSE;
count = 0;
}
}
}
#ifndef BASIC
void PBI_BB_StateSave(void)
{
StateSav_SaveINT(&PBI_BB_enabled, 1);
if (PBI_BB_enabled) {
StateSav_SaveFNAME(bb_scsi_disk_filename);
StateSav_SaveFNAME(bb_rom_filename);
StateSav_SaveINT(&bb_ram_bank_offset, 1);
StateSav_SaveUBYTE(bb_ram, BB_RAM_SIZE);
StateSav_SaveUBYTE(&bb_rom_bank, 1);
StateSav_SaveINT(&bb_rom_high_bit, 1);
StateSav_SaveUBYTE(&bb_PCR, 1);
}
}
void PBI_BB_StateRead(void)
{
StateSav_ReadINT(&PBI_BB_enabled, 1);
if (PBI_BB_enabled) {
StateSav_ReadFNAME(bb_scsi_disk_filename);
StateSav_ReadFNAME(bb_rom_filename);
init_bb();
StateSav_ReadINT(&bb_ram_bank_offset, 1);
StateSav_ReadUBYTE(bb_ram, BB_RAM_SIZE);
StateSav_ReadUBYTE(&bb_rom_bank, 1);
StateSav_ReadINT(&bb_rom_high_bit, 1);
StateSav_ReadUBYTE(&bb_PCR, 1);
}
}
#endif /* #ifndef BASIC */
/*
vim:ts=4:sw=4:
*/
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