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6830 cleanup, 6502 class visibility cleanup
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@wfd3
wfd3 committed Jan 3, 2024
1 parent 27f7abd commit 36edfed
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Showing 5 changed files with 115 additions and 90 deletions.
122 changes: 64 additions & 58 deletions apple1/mos6820.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,8 @@
#include <queue>
#include <algorithm>

#include "memory.h"

#if defined(__linux__) || defined(__MACH__)
#include <unistd.h>
# ifdef __linux__
Expand All @@ -36,12 +38,8 @@
#elif defined(_WIN64)
# include <conio.h>
# include <windows.h>
#else
# error "No platform-specific implementation of getch()"
#endif

#include "memory.h"

template<class Address = uint16_t, class Cell = uint8_t>
class MOS6820 : public MemMappedDevice<Address, Cell> {
public:
Expand Down Expand Up @@ -141,34 +139,37 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
private:

// Offsets from MemMappedDevice::_baseAddress for these memory-mapped I/O ports. These are in order
// and cannot change.
// and cannot change as they, when added to _baseAddress, represent hardware addresses of where this
// chip is mapped in memory.
static constexpr Word KEYBOARD = 0;
static constexpr Word KEYBOARDCR = 1;
static constexpr Word DISPLAY = 2;
static constexpr Word DISPLAYCR = 3;

// Apple 1 keycodes
static constexpr char NEWLINE = 0x0a;
static constexpr char CARRAGE_RETURN = 0x0d;
static constexpr char BELL = 0x0a;
static constexpr char NEWLINE = 0x0a;
static constexpr char CARRIAGE_RETURN = 0x0d;
static constexpr char BACKSPACE = '_';
static constexpr char BELL = 0x0a;
static constexpr char CTRL_C = 0x03;
#ifdef _WIN64
static constexpr char CTRL_C = 0x03;
static constexpr char DEL = '\b';
static constexpr char CTRL_BACKSPACE = 0x7f; // Quit emulator
static constexpr char DEL = '\b';
static constexpr char CTRL_BACKSPACE = 0x7f; // Quit emulator
#else
static constexpr char DEL = 0x7f; // Backspace on unix/linux
static constexpr char CTRL_BACKSPACE = 0x08;
static constexpr char DEL = 0x7f; // Backspace on unix/linux
static constexpr char CTRL_BACKSPACE = 0x08;
#endif
static constexpr char CTRL_LBRACKET = 0x1b; // Clear screen
static constexpr char CTRL_BACKSLASH = 0x1c; // Reset/Jump to Wozmon
static constexpr char CTRL_RBRACKET = 0x1d; // Enter debugger
static constexpr char CTRL_LBRACKET = 0x1b; // Clear screen
static constexpr char CTRL_BACKSLASH = 0x1c; // Reset/Jump to Wozmon
static constexpr char CTRL_RBRACKET = 0x1d; // Enter debugger

// Platform agnostic remapping of control keycodes. These are encoded in getch() and returned
// as a signed char, and should be non-printable ASCII characters.
static constexpr char CLEARSCR_CHAR = 0x00;
static constexpr char RESET_CHAR = 0x01;
static constexpr char DEBUGGER_CHAR = 0x02; // 0x03 is Control-C
static constexpr char EXIT_CHAR = 0x04;
// as a Cell. They must be non-printable ASCII characters on the Apple 1 (ie, extended
// ASCII codes).
static constexpr Cell CLEAR_SCREEN = 0xff;
static constexpr Cell RESET = 0xfe;
static constexpr Cell DEBUGGER = 0xfd;
static constexpr Cell EXIT = 0xfc;

// Display
bool _haveDspData = false;
Expand All @@ -180,7 +181,7 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {

#if defined(__linux__) || defined(__MACH__)

bool getch(char &kbdCh) const {
bool getch(Cell &kbdCh) const {
int byteswaiting;
char ch;

Expand All @@ -192,16 +193,16 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {

switch (ch) {
case CTRL_BACKSPACE:
kbdCh = EXIT_CHAR;
kbdCh = EXIT;
break;
case CTRL_BACKSLASH:
kbdCh = RESET_CHAR;
kbdCh = RESET;
break;
case CTRL_RBRACKET:
kbdCh = DEBUGGER_CHAR;
kbdCh = DEBUGGER;
break;
case CTRL_LBRACKET:
kbdCh = CLEARSCR_CHAR;
kbdCh = CLEAR_SCREEN;
break;
default:
kbdCh = ch;
Expand Down Expand Up @@ -233,7 +234,7 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
system("cls");
}

bool getch(char& kbdCh) const {
bool getch(Cell& kbdCh) const {

if (_CtrlC_Pressed) {
_CtrlC_Pressed = false;
Expand All @@ -248,16 +249,16 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
if (GetAsyncKeyState(VK_CONTROL) < 0) { // Control was held when key was pressed
switch (c) {
case CTRL_BACKSPACE:
kbdCh = EXIT_CHAR;
kbdCh = EXIT;
return true;
case CTRL_BACKSLASH:
kbdCh = RESET_CHAR;
kbdCh = RESET;
return true;
case CTRL_LBRACKET:
kbdCh = CLEARSCR_CHAR;
kbdCh = CLEAR_SCREEN;
return true;
case CTRL_RBRACKET:
kbdCh = DEBUGGER_CHAR;
kbdCh = DEBUGGER;
return true;
}
}
Expand All @@ -267,16 +268,7 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
}

#else

// Clear the Apple 1 display
void clearScreen() const {}

// Check and get a key from the keyboard, returning true and setting kbdCh if a key was ready
// for us. Map Control keys to platform agnostic values (see above)
bool getch(char& kbdCh) {
return false;
}

# error "No platform specific clearScreen() or getch() functions defined"
#endif

Device::Lines displayHousekeeping() {
Expand All @@ -285,13 +277,13 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {

auto c = _dspData & 0x7f; // clear hi bit
switch (c) {
case CARRAGE_RETURN: // \r
case CARRIAGE_RETURN:
fmt::print("\n");
break;
case '_': // Backspace
case BACKSPACE:
fmt::print("\b");
break;
case BELL: // Bell
case BELL:
fmt::print("\a");
break;
default:
Expand All @@ -304,7 +296,8 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
}

Device::Lines keyboardHousekeeping() {
char ch;
Cell ch;
bool clobberQueue = false;
auto retval = Device::None;

auto charsPending = getch(ch);
Expand All @@ -314,32 +307,43 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
// Handle control characters or map modern ascii to Apple 1 keycodes
switch (ch) {

// Control characters; don't queue these.
case RESET_CHAR:
// Control values; don't queue these.
case RESET:
return Device::Reset;

case DEBUGGER_CHAR:
case DEBUGGER:
return Device::Debug;

case EXIT_CHAR:
case EXIT:
return Device::Exit;

case CLEARSCR_CHAR:
case CLEAR_SCREEN:
clearScreen();
return Device::None;

// Control-C is special, see the Applesoft basic comments below.
case CTRL_C:
clobberQueue = true;
break;

// Regular characters; do queue these
case NEWLINE:
ch = CARRAGE_RETURN;
ch = CARRIAGE_RETURN;
break;

case DEL:
ch = '_';
ch = BACKSPACE;
break;
}

// Apple 1 expects only upper case characters and that the high bit will be set
ch = std::toupper(ch);
ch |= 0x80;
ch |= 0x80;

if (clobberQueue)
while (!_charQueue.empty())
_charQueue.pop();

_charQueue.push(ch);

return retval;
Expand Down Expand Up @@ -386,9 +390,12 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
// Applesoft Basic Lite does a blind, unchecked read on the keyboard port
// looking for a ^C. If it sees one, it then does a read on the keyboard
// control register followed by a read of the keyboard port, expecting to
// get the same ^C. This logic forces a keyboard control register read
// before removing the character from the queue, thus preventing an
// infinite loop.
// get the same ^C. This logic forces a keyboard control register read
// before removing the character from the queue, thus preventing an
// infinite loop. This also means that if the user hits ^C but the data element
// at the head of _charQueue is something else, the ^C will never be seen and processed.
// We fix this by clobbering the _charQueue before queuing the ^C. We do this in
// keyboardHousekeeping() above.
if (_kbdCRRead) {
_charQueue.pop();
_kbdCRRead = false;
Expand All @@ -404,6 +411,5 @@ class MOS6820 : public MemMappedDevice<Address, Cell> {
};

#ifdef _WIN64
template <typename Address, typename Cell>
bool MOS6820<Address, Cell>::_CtrlC_Pressed = false;
template <typename Address, typename Cell> bool MOS6820<Address, Cell>::_CtrlC_Pressed = false;
#endif
12 changes: 8 additions & 4 deletions src/6502.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,16 +37,18 @@ void CPU::setInterruptVector(Word address) {
}

void CPU::exitReset() {
PC = readWord(RESET_VECTOR);
SP = INITIAL_SP;

#ifdef TEST_BUILD
// If we're here via TestReset() clobber the PC and SP with test values
if (_testReset) {
SP = testResetSP;
PC = testResetPC;
} else {
PC = readWord(RESET_VECTOR);
SP = INITIAL_SP;
}

_testReset = false;
#endif

_debuggingEnabled = false;
debug_alwaysShowPS = false;

Expand All @@ -62,13 +64,15 @@ void CPU::exitReset() {
// allows tests to set specific starting Program Counter and
// Stack Pointer values, and arranges for the next call to execute...()
// to exit the CPU from reset.
#ifdef TEST_BUILD
void CPU::TestReset(Word initialPC, Byte initialSP) {
_inReset = false;
_pendingReset = true;
_testReset = true;
testResetPC = initialPC;
testResetSP = initialSP;
}
#endif

// 'Asserts' the Reset line if not asserted, de-asserts the Reset line
// if asserted.
Expand Down
11 changes: 9 additions & 2 deletions src/6502.h
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Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,6 @@ class CPU {
// CPU Setup & reset
CPU(cMemory &);
void Reset();
void TestReset(Word initialPC = RESET_VECTOR, Byte initialSP = INITIAL_SP);
void setResetVector(Word);
void setPendingReset() {
if (!_debuggingEnabled)
Expand Down Expand Up @@ -97,7 +96,11 @@ class CPU {
// Debugger
bool executeDebug();

#ifdef TEST_BUILD
public:
#else
private:
#endif

//////////
// Used by tests
Expand Down Expand Up @@ -127,7 +130,9 @@ class CPU {
Byte PS = 0;
struct ProcessorStatusBits Flags;
};

#ifdef TEST_BUILD
void TestReset(Word initialPC = RESET_VECTOR, Byte initialSP = INITIAL_SP);
#endif
void executeOneInstructionWithCycleCount(Cycles_t &, Cycles_t &);
bool executeOneInstruction();
void traceOneInstruction(Cycles_t &, Cycles_t &);
Expand Down Expand Up @@ -182,9 +187,11 @@ class CPU {
std::atomic_bool _pendingIRQ = false;
std::atomic_bool _pendingNMI = false;
bool _hitException = false;
#ifdef TEST_BUILD
Word testResetPC = 0;
Byte testResetSP = INITIAL_SP;
bool _testReset = false;
#endif
Address_t _haltAddress = 0;
bool _haltAddressSet = false;

Expand Down
4 changes: 3 additions & 1 deletion src/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ cmake_minimum_required(VERSION 3.7)

project( lib6502 )

set (SOURCES
set (SOURCES
"6502.h"
"clock.h"
"memory.h"
Expand All @@ -30,3 +30,5 @@ include_directories(AFTER ${fmt_INCLUDE_DIRS})
add_library( 6502 ${SOURCES} )
target_compile_definitions(6502 PRIVATE FMT_HEADER_ONLY)

add_library( 6502-test ${SOURCES})
target_compile_definitions(6502-test PRIVATE FMT_HEADER_ONLY TEST_BUILD)
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