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aiie/apple/applemmu.cpp

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#ifdef TEENSYDUINO
#include <Arduino.h>
#else
#include <stdio.h>
#include <unistd.h>
#endif
#include "applemmu.h"
#include "applemmu-rom.h"
#include "physicalspeaker.h"
#include "cpu.h"
#include "mockingboard.h"
#include "globals.h"
// apple //e memory map
/*
page 0x00: zero page (straight ram)
page 0x01: stack (straight ram)
page 0x02:
page 0x03:
text/lores page 1: 0x0400 - 0x7FF
text/lores page 2: 0x0800 - 0xBFF
pages 0x0C - 0x1F: straight ram
hires page 1: pages 0x20 - 0x3F
hires page 2: pages 0x40 - 0x5F
pages 0x60 - 0xBF: straight ram
page 0xc0: I/O switches
pages 0xc1 - 0xcf: slot ROMs
pages 0xd0 - 0xdf: Basic ROM
pages 0xe0 - 0xff: monitor ROM
*/
AppleMMU::AppleMMU(AppleDisplay *display)
{
anyKeyDown = false;
keyboardStrobe = 0x00;
isOpenApplePressed = false;
isClosedApplePressed = false;
for (int8_t i=0; i<=7; i++) {
slots[i] = NULL;
}
allocateMemory();
this->display = display;
this->display->setSwitches(&switches);
resetRAM(); // initialize RAM, load ROM
}
AppleMMU::~AppleMMU()
{
delete display;
// FIXME: clean up the memory we allocated
}
void AppleMMU::Reset()
{
resetRAM();
resetDisplay(); // sets the switches properly
}
uint8_t AppleMMU::read(uint16_t address)
{
if (address >= 0xC000 &&
address <= 0xC0FF) {
return readSwitches(address);
}
// FIXME: assumes slot 4 is a mockingboard
if (slots[4] && address >= 0xC400 && address <= 0xC4FF) {
return ((Mockingboard *)slots[4])->read(address);
}
uint8_t res = readPages[(address & 0xFF00) >> 8][address & 0xFF];
return res;
}
// Bypass MMU and read directly from a given page - also bypasses switches
uint8_t AppleMMU::readDirect(uint16_t address, uint8_t fromPage)
{
return ramPages[(address & 0xFF00) >> 8][fromPage][address & 0xFF];
}
void AppleMMU::write(uint16_t address, uint8_t v)
{
if (address >= 0xC000 &&
address <= 0xC0FF) {
return writeSwitches(address, v);
}
// FIXME: assumes slot4 is a mockingboard
if (slots[4] && address >= 0xC400 && address <= 0xC4FF) {
((Mockingboard *)slots[4])->write(address, v);
return;
}
// Don't allow writes to ROM
if (address >= 0xC100 && address <= 0xCFFF)
return;
if (address >= 0xD000 && address <= 0xFFFF && !writebsr) {
// memory-protected, so don't allow writes
return;
}
writePages[(address & 0xFF00) >> 8][address & 0xFF] = v;
if (address >= 0x400 &&
address <= 0x7FF) {
// If it's text mode, or mixed mode, or lores graphics mode, then update.
if ((switches & S_TEXT) || (switches & S_MIXED) || (!(switches & S_HIRES))) {
// Force a redraw
display->modeChange();
}
return;
}
if (address >= 0x2000 &&
address <= 0x5FFF) {
if (switches & S_HIRES) {
// Force a redraw
display->modeChange();
}
}
}
// FIXME: this is no longer "MMU", is it?
void AppleMMU::resetDisplay()
{
updateMemoryPages();
display->modeChange();
}
void AppleMMU::handleMemorySwitches(uint16_t address, uint16_t lastSwitch)
{
// many of these are spelled out here:
// http://apple2.org.za/gswv/a2zine/faqs/csa2pfaq.html
switch (address) {
// These are write-only and perform no action on read
case 0xC000: // CLR80STORE
switches &= ~S_80STORE;
updateMemoryPages();
break;
case 0xC001: // SET80STORE
switches |= S_80STORE;
updateMemoryPages();
break;
case 0xC002: // CLRAUXRD read from main 48k RAM
auxRamRead = false;
break;
case 0xC003: // SETAUXRD read from aux/alt 48k
auxRamRead = true;
break;
case 0xC004: // CLRAUXWR write to main 48k RAM
auxRamWrite = false;
break;
case 0xC005: // SETAUXWR write to aux/alt 48k
auxRamWrite = true;
break;
case 0xC006: // CLRCXROM use ROM on cards
intcxrom = false;
break;
case 0xC007: // SETCXROM use internal ROM
intcxrom = true;
break;
case 0xC008: // CLRAUXZP use main zero page, stack, LC
altzp = false;
break;
case 0xC009: // SETAUXZP use alt zero page, stack, LC
altzp = true;
break;
case 0xC00A: // CLRC3ROM use internal slot 3 ROM
slot3rom = false;
break;
case 0xC00B: // SETC3ROM use external slot 3 ROM
slot3rom = true;
break;
// these are probably read/write ?
case 0xC080: // READBSR2 and shadow copy
case 0xC084:
bank1 = false; // LC RAM bank2, Read and Write-prot RAM
readbsr = true; // read from bank2
writebsr = false; // write-protected
break;
case 0xC081: // ROMIN
case 0xC085:
bank1 = false; // LC RAM bank2, read ROM, write-enable RAM
readbsr = false; // if it's read twice in a row
writebsr = writebsr || ((lastSwitch & 0xF3) == (address & 0xF3));
break;
case 0xC082:
case 0xC086:
bank1 = false; // LC RAM bank2, Read ROM instead of RAM,
readbsr = false; // WR-protect RAM
writebsr = false;
break;
case 0xC083: // READWRBSR2
case 0xC087:
bank1 = false;
readbsr = true;
writebsr = writebsr || ((lastSwitch & 0xF3) == (address & 0xF3));
break;
case 0xC088: // READBSR1
case 0xC08C:
bank1 = true;
readbsr = true;
writebsr = false;
break;
case 0xC089: // WRITEBSR1
case 0xC08D:
bank1 = true;
readbsr = false;
writebsr = writebsr || ((lastSwitch & 0xF3) == (address & 0xF3));
break;
case 0xC08A: // OFFBSR1
case 0xC08E:
bank1 = true;
readbsr = false;
writebsr = false;
break;
case 0xC08B: // READWRBSR1
case 0xC08F:
bank1 = true;
readbsr = true;
writebsr = writebsr || ((lastSwitch & 0xF3) == (address & 0xF3));
break;
}
updateMemoryPages();
}
// many (most? all?) switches are documented here:
// http://apple2.org.za/gswv/a2zine/faqs/csa2pfaq.html
uint8_t AppleMMU::readSwitches(uint16_t address)
{
static uint16_t lastReadSwitch = 0x0000;
static uint16_t thisReadSwitch = 0x0000;
lastReadSwitch = thisReadSwitch;
thisReadSwitch = address;
// If this is a read for any of the slot switches, and we have
// hardware in that slot, then return its result.
if (address >= 0xC090 && address <= 0xC0FF) {
for (uint8_t i=1; i<=7; i++) {
if (address >= (0xC080 | (i << 4)) &&
address <= (0xC08F | (i << 4))) {
if (slots[i]) {
return slots[i]->readSwitches(address & ~(0xC080 | (i<<4)));
}
else
return FLOATING;
}
}
}
switch (address) {
case 0xC010:
// consume the keyboard strobe flag
keyboardStrobe &= 0x7F;
return (anyKeyDown ? 0x80 : 0x00);
#if 0
case 0xC000:
case 0xC001:
case 0xC002:
case 0xC003:
case 0xC004:
case 0xC005:
case 0xC006:
case 0xC007:
case 0xC008:
case 0xC009:
case 0xC00A:
case 0xC00B:
// nothing happens in read mode for these, so don't call this:
// handleMemorySwitches(address, lastReadSwitch);
case 0xC00C:
case 0xC00D:
case 0xC00E:
case 0xC00F:
// But according to UTA2E, these ALL return keyboard strobe data.
// We do that after the switch statement so we get the other affects
// from reads to these addresses within the switch statement.
break;
#endif
case 0xC080:
case 0xC081:
case 0xC082:
case 0xC083:
case 0xC084:
case 0xC085:
case 0xC086:
case 0xC087:
case 0xC088:
case 0xC089:
case 0xC08A:
case 0xC08B:
case 0xC08C:
case 0xC08D:
case 0xC08E:
case 0xC08F:
// but read does affect these, same as write
handleMemorySwitches(address, lastReadSwitch);
break;
case 0xC00C: // CLR80VID disable 80-col video mode
if (switches & S_80COL) {
switches &= ~S_80COL;
resetDisplay();
}
break;
case 0xC00D: // SET80VID enable 80-col video mode
if (!(switches & S_80COL)) {
switches |= S_80COL;
resetDisplay();
}
break;
case 0xC00E: // CLRALTCH use main char set - norm LC, flash UC
switches &= ~S_ALTCH;
break;
case 0xC00F: // SETALTCH use alt char set - norm inverse, LC; no flash
switches |= S_ALTCH;
break;
case 0xC011: // RDLCBNK2
return bank1 ? 0x00 : 0x80;
case 0xC012: // RDLCRAM
return readbsr ? 0x80 : 0x00;
case 0xC013: // RDRAMRD
return auxRamRead ? 0x80 : 0x00;
case 0xC014: // RDRAMWR
return auxRamWrite ? 0x80 : 0x00;
case 0xC015: // RDCXROM
return intcxrom ? 0x80 : 0x00;
case 0xC016: // RDAUXZP
return altzp ? 0x80 : 0x00;
case 0xC017: // RDC3ROM
return slot3rom ? 0x80 : 0x00;
case 0xC018: // RD80COL
return (switches & S_80STORE) ? 0x80 : 0x00;
// 0xC019: RDVBLBAR -- is the vertical blanking low?
case 0xC01A: // RDTEXT
return ( (switches & S_TEXT) ? 0x80 : 0x00 );
case 0xC01B: // RDMIXED
return ( (switches & S_MIXED) ? 0x80 : 0x00 );
case 0xC01C: // RDPAGE2
return ( (switches & S_PAGE2) ? 0x80 : 0x00 );
case 0xC01D: // RDHIRES
return ( (switches & S_HIRES) ? 0x80 : 0x00 );
case 0xC01E: // RDALTCH
return ( (switches & S_ALTCH) ? 0x80 : 0x00 );
case 0xC01F: // RD80VID
return ( (switches & S_80COL) ? 0x80 : 0x00 );
case 0xC030: // SPEAKER
g_speaker->toggle();
break;
case 0xC050: // CLRTEXT
if (switches & S_TEXT) {
switches &= ~S_TEXT;
resetDisplay();
}
return FLOATING;
case 0xC051: // SETTEXT
if (!(switches & S_TEXT)) {
switches |= S_TEXT;
resetDisplay();
}
return FLOATING;
case 0xC052: // CLRMIXED
if (switches & S_MIXED) {
switches &= ~S_MIXED;
resetDisplay();
}
return FLOATING;
case 0xC053: // SETMIXED
if (!(switches & S_MIXED)) {
switches |= S_MIXED;
resetDisplay();
}
return FLOATING;
case 0xC054: // PAGE1
if (switches & S_PAGE2) {
switches &= ~S_PAGE2;
if (!(switches & S_80COL)) {
resetDisplay();
} else {
updateMemoryPages();
}
}
return FLOATING;
case 0xC055: // PAGE2
if (!(switches & S_PAGE2)) {
switches |= S_PAGE2;
if (!(switches & S_80COL)) {
resetDisplay();
} else {
updateMemoryPages();
}
}
return FLOATING;
case 0xC056: // CLRHIRES
if (switches & S_HIRES) {
switches &= ~S_HIRES;
resetDisplay();
}
return FLOATING;
case 0xC057: // SETHIRES
if (!(switches & S_HIRES)) {
switches |= S_HIRES;
resetDisplay();
}
return FLOATING;
case 0xC05E: // DHIRES ON
if (!(switches & S_DHIRES)) {
switches |= S_DHIRES;
resetDisplay();
}
return FLOATING;
case 0xC05F: // DHIRES OFF
if (switches & S_DHIRES) {
switches &= ~S_DHIRES;
resetDisplay();
}
return FLOATING;
// paddles
case 0xC061: // OPNAPPLE
return isOpenApplePressed ? 0x80 : 0x00;
case 0xC062: // CLSAPPLE
return isClosedApplePressed ? 0x80 : 0x00;
case 0xC070: // PDLTRIG
// It doesn't matter if we update readPages or writePages, because 0xC0
// has only one page.
readPages[0xC0][0x64] = readPages[0xC0][0x65] = 0xFF;
g_paddles->startReading();
return FLOATING;
}
if (address >= 0xc000 && address <= 0xc00f) {
// This is the keyboardStrobe support referenced in the switch statement above.
return keyboardStrobe;
}
return readPages[address >> 8][address & 0xFF];
}
void AppleMMU::writeSwitches(uint16_t address, uint8_t v)
{
// fixme: combine these with the last read switch
static uint16_t lastWriteSwitch = 0x0000;
static uint16_t thisWriteSwitch = 0x0000;
lastWriteSwitch = thisWriteSwitch;
thisWriteSwitch = address;
// If this is a write for any of the slot switches, and we have
// hardware in that slot, then return its result.
if (address >= 0xC090 && address <= 0xC0FF) {
for (uint8_t i=1; i<=7; i++) {
if (address >= (0xC080 | (i << 4)) &&
address <= (0xC08F | (i << 4))) {
if (slots[i]) {
slots[i]->writeSwitches(address & ~(0xC080 | (i<<4)), v);
return;
}
}
}
}
switch (address) {
case 0xC010:
case 0xC011: // Per Understanding the Apple //e, p. 7-3:
case 0xC012: // a write to any $C01x address causes
case 0xC013: // a clear of the keyboard strobe.
case 0xC014:
case 0xC015:
case 0xC016:
case 0xC017:
case 0xC018:
case 0xC019:
case 0xC01A:
case 0xC01B:
case 0xC01C:
case 0xC01D:
case 0xC01E:
case 0xC01F:
keyboardStrobe &= 0x7F;
return;
case 0xC050: // graphics mode
if (switches & S_TEXT) {
switches &= ~S_TEXT;
resetDisplay();
}
return;
case 0xC051:
if (!(switches & S_TEXT)) {
switches |= S_TEXT;
resetDisplay();
}
return;
case 0xC052: // "no mixed"
if (switches & S_MIXED) {
switches &= ~S_MIXED;
resetDisplay();
}
return;
case 0xC053: // "mixed"
if (!(switches & S_MIXED)) {
switches |= S_MIXED;
resetDisplay();
}
return;
case 0xC054: // page2 off
if (switches & S_PAGE2) {
switches &= ~S_PAGE2;
if (!(switches & S_80COL)) {
resetDisplay();
} else {
updateMemoryPages();
}
}
return;
case 0xC055: // page2 on
if (!(switches & S_PAGE2)) {
switches |= S_PAGE2;
if (!(switches & S_80COL)) {
resetDisplay();
} else {
updateMemoryPages();
}
}
return;
case 0xC056: // hires off
if (switches & S_HIRES) {
switches &= ~S_HIRES;
resetDisplay();
}
return;
case 0xC057: // hires on
if (!(switches & S_HIRES)) {
switches |= S_HIRES;
resetDisplay();
}
return;
case 0xC05E: // DHIRES ON
if (!(switches & S_DHIRES)) {
switches |= S_DHIRES;
resetDisplay();
}
return;
case 0xC05F: // DHIRES OFF
if (switches & S_DHIRES) {
switches &= ~S_DHIRES;
resetDisplay();
}
return;
// paddles
case 0xC070:
g_paddles->startReading();
writePages[0xC0][0x64] = writePages[0xC0][0x65] = 0xFF;
break;
case 0xC000:
case 0xC001:
case 0xC002:
case 0xC003:
case 0xC004:
case 0xC005:
case 0xC006:
case 0xC007:
case 0xC008:
case 0xC009:
case 0xC00A:
case 0xC00B:
case 0xC080:
case 0xC081:
case 0xC082:
case 0xC083:
case 0xC084:
case 0xC085:
case 0xC086:
case 0xC087:
case 0xC088:
case 0xC089:
case 0xC08A:
case 0xC08B:
case 0xC08C:
case 0xC08D:
case 0xC08E:
case 0xC08F:
handleMemorySwitches(address, lastWriteSwitch);
break;
case 0xC00C: // CLR80VID disable 80-col video mode
if (switches & S_80COL) {
switches &= ~S_80COL;
resetDisplay();
}
break;
case 0xC00D: // SET80VID enable 80-col video mode
if (!(switches & S_80COL)) {
switches |= S_80COL;
resetDisplay();
}
break;
case 0xC00E: // CLRALTCH use main char set - norm LC, flash UC
switches &= ~S_ALTCH;
break;
case 0xC00F: // SETALTCH use alt char set - norm inverse, LC; no flash
switches |= S_ALTCH;
break;
}
}
void AppleMMU::keyboardInput(uint8_t v)
{
keyboardStrobe = v | 0x80;
anyKeyDown = true;
}
void AppleMMU::setKeyDown(bool isTrue)
{
anyKeyDown = isTrue;
}
void AppleMMU::triggerPaddleTimer(uint8_t paddle)
{
writePages[0xC0][0x64 + paddle] = 0x00;
}
void AppleMMU::resetRAM()
{
switches = S_TEXT;
bank1 = true;
auxRamRead = auxRamWrite = false;
readbsr = writebsr = false;
altzp = false;
intcxrom = false;
slot3rom = false;
for (uint8_t i=0; i<0xFF; i++) {
for (uint8_t j=0; j<5; j++) {
if (ramPages[i][j]) {
for (uint16_t k=0; k<0x100; k++) {
ramPages[i][j][k] = 0;
}
}
}
readPages[i] = writePages[i] = ramPages[i][0];
}
// Load ROM
#ifdef TEENSYDUINO
for (uint16_t i=0x80; i<=0xFF; i++) {
for (uint16_t k=0; k<0x100; k++) {
uint16_t idx = ((i-0x80) << 8) | k;
uint8_t v = pgm_read_byte(&romData[idx]);
for (uint8_t j=0; j<5; j++) {
if (ramPages[i][j]) {
ramPages[i][j][k] = v;
}
}
}
}
#else
for (uint16_t i=0x80; i<=0xFF; i++) {
for (uint16_t k=0; k<0x100; k++) {
uint16_t idx = ((i-0x80) << 8) | k;
uint8_t v = romData[idx];
for (uint8_t j=0; j<5; j++) {
if (ramPages[i][j]) {
ramPages[i][j][k] = v;
}
}
}
}
#endif
for (uint8_t slotnum = 0; slotnum <= 7; slotnum++) {
if (slots[slotnum]) {
slots[slotnum]->loadROM(ramPages[0xC0 + slotnum][0]);
}
}
}
void AppleMMU::setSlot(int8_t slotnum, Slot *peripheral)
{
slots[slotnum] = peripheral;
if (slots[slotnum]) {
slots[slotnum]->loadROM(ramPages[0xC0 + slotnum][0]);
}
}
void AppleMMU::allocateMemory()
{
for (uint16_t i=0; i<0xC0; i++) {
for (uint8_t j=0; j<2; j++) {
ramPages[i][j] = (uint8_t *)malloc(0x100);
}
for (uint8_t j=2; j<5; j++) {
ramPages[i][j] = NULL;
}
readPages[i] = ramPages[i][0];
writePages[i] = ramPages[i][0];
}
for (uint16_t i=0xC0; i<0x100; i++) {
for (uint8_t j=0; j<5; j++) {
ramPages[i][j] = (uint8_t *)malloc(0x100);
}
readPages[i] = ramPages[i][0];
writePages[i] = ramPages[i][0];
}
}
void AppleMMU::updateMemoryPages()
{
if (auxRamRead) {
for (uint8_t idx = 0x02; idx < 0xc0; idx++) {
readPages[idx] = ramPages[idx][1];
}
} else {
for (uint8_t idx = 0x02; idx < 0xc0; idx++) {
readPages[idx] = ramPages[idx][0];
}
}
if (auxRamWrite) {
for (uint8_t idx = 0x02; idx < 0xc0; idx++) {
writePages[idx] = ramPages[idx][1];
}
} else {
for (uint8_t idx = 0x02; idx < 0xc0; idx++) {
writePages[idx] = ramPages[idx][0];
}
}
if (switches & S_80STORE) {
if (switches & S_PAGE2) {
for (uint8_t idx = 0x04; idx < 0x08; idx++) {
readPages[idx] = ramPages[idx][1];
writePages[idx] = ramPages[idx][1];
}
// If HIRES is on, then we honor the PAGE2 setting; otherwise, we don't
for (uint8_t idx = 0x20; idx < 0x40; idx++) {
readPages[idx] = ramPages[idx][(switches & S_HIRES) ? 1 : 0];
writePages[idx] = ramPages[idx][(switches & S_HIRES) ? 1 : 0];
}
} else {
for (uint8_t idx = 0x04; idx < 0x08; idx++) {
readPages[idx] = ramPages[idx][0];
writePages[idx] = ramPages[idx][0];
}
if (switches & S_HIRES) {
// PAGE2 is off, so we set this back to 0 regardless
for (uint8_t idx = 0x20; idx < 0x40; idx++) {
readPages[idx] = ramPages[idx][0];
writePages[idx] = ramPages[idx][0];
}
}
}
}
if (intcxrom) {
for (uint8_t idx = 0xc1; idx < 0xd0; idx++) {
readPages[idx] = ramPages[idx][1];
}
} else {
for (uint8_t idx = 0xc1; idx < 0xd0; idx++) {
readPages[idx] = ramPages[idx][0];
}
}
if (altzp) {
for (uint8_t idx = 0x00; idx < 0x02; idx++) {
readPages[idx] = ramPages[idx][1];
writePages[idx] = ramPages[idx][1];
}
} else {
for (uint8_t idx = 0x00; idx < 0x02; idx++) {
readPages[idx] = ramPages[idx][0];
writePages[idx] = ramPages[idx][0];
}
}
if (readbsr) {
if (bank1) {
for (uint8_t idx = 0xd0; idx < 0xe0; idx++) {
readPages[idx] = ramPages[idx][altzp ? 2 : 1];
}
} else {
for (uint8_t idx = 0xd0; idx < 0xe0; idx++) {
readPages[idx] = ramPages[idx][altzp ? 4 : 3];
}
}
for (uint16_t idx = 0xe0; idx < 0x100; idx++) {
readPages[idx] = ramPages[idx][altzp ? 2 : 1];
}
} else {
for (uint16_t idx = 0xd0; idx < 0x100; idx++) {
readPages[idx] = ramPages[idx][0];
}
}
if (writebsr) {
if (bank1) {
for (uint8_t idx = 0xd0; idx < 0xe0; idx++) {
writePages[idx] = ramPages[idx][altzp ? 2 : 1];
}
} else {
for (uint8_t idx = 0xd0; idx < 0xe0; idx++) {
writePages[idx] = ramPages[idx][altzp ? 4 : 3];
}
}
for (uint16_t idx = 0xe0; idx < 0x100; idx++) {
writePages[idx] = ramPages[idx][altzp ? 2 : 1];
}
} else {
for (uint16_t idx = 0xd0; idx < 0x100; idx++) {
writePages[idx] = ramPages[idx][0];
}
}
}
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