AtomBusMon/firmware/AtomBusMon.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <avr/pgmspace.h>

#include "AtomBusMon.h"

/********************************************************
 * VERSION and NAME are used in the start-up message
 ********************************************************/

#define VERSION "0.72"

#if (CPU == Z80)
  #define NAME "ICE-T80"
#elif (CPU == 6502)
  #define NAME "ICE-T65"
#elif (CPU == 6809)
  #define NAME "ICE-6809"
#else
  #error "Unsupported CPU type"
#endif

/********************************************************
 * User Command Definitions
 ********************************************************/

#ifdef CPUEMBEDDED
  #if (CPU == Z80)
    #define NUM_CMDS 29
  #else
    #define NUM_CMDS 22
  #endif
#else
  #define NUM_CMDS 14
#endif

// The command process accepts abbreviated forms, for example
// if h is entered, then help will match.

// Must be kept in step with cmdFuncs (just below)
char *cmdStrings[NUM_CMDS] = {
  "help",
  "continue",
#ifdef CPUEMBEDDED
  "regs",
  "dis",
  "fill",
  "crc",
  "mem",
  "rdm",
  "wrm",
#if (CPU == Z80)
  "io",
  "rdi",
  "wri",
#endif
  "test",
#endif
  "reset",
  "step",
  "trace",
  "blist",
  "breakx",
  "watchx",
  "breakrm",
  "watchrm",
  "breakwm",
  "watchwm",
#if (CPU == Z80)
  "breakri",
  "watchri",
  "breakwi",
  "watchwi",
#endif
  "clear",
  "trigger"
};

// Must be kept in step with cmdStrings (just above)
void (*cmdFuncs[NUM_CMDS])(char *params) = {
  doCmdHelp,
  doCmdContinue,
#ifdef CPUEMBEDDED
  doCmdRegs,
  doCmdDis,
  doCmdFill,
  doCmdCrc,
  doCmdMem,
  doCmdReadMem,
  doCmdWriteMem,
#if (CPU == Z80)
  doCmdIO,
  doCmdReadIO,
  doCmdWriteIO,
#endif
  doCmdTest,
#endif
  doCmdReset,
  doCmdStep,
  doCmdTrace,
  doCmdList,
  doCmdBreakI,
  doCmdWatchI,
  doCmdBreakRdMem,
  doCmdWatchRdMem,
  doCmdBreakWrMem,
  doCmdWatchWrMem,
#if (CPU == Z80)
  doCmdBreakRdIO,
  doCmdWatchRdIO,
  doCmdBreakWrIO,
  doCmdWatchWrIO,
#endif
  doCmdClear,
  doCmdTrigger
};

/********************************************************
 * AVR Control Register Definitions
 ********************************************************/

// The control register allows commands to be sent to the AVR
#define CTRL_PORT         PORTB
#define CTRL_DDR          DDRB
#define CTRL_DIN          PINB

// A 0->1 transition on bit 5 actually sends a command
#define CMD_EDGE          0x20

// Commands are placed on bits 4..0
// Currently bits 6 and 7 are unused
#define CMD_MASK          0x3F

// Hardware Commands:
//
// 0000x Enable/Disable single strpping
// 0001x Enable/Disable breakpoints / watches
// 0010x Load breakpoint / watch register
// 0011x Reset CPU
// 01000 Singe Step CPU
// 01001 Read FIFO
// 01010 Reset FIFO
// 01011 Unused
// 0110x Load address/data register
// 0111x Unused
// 10000 Read Memory
// 10001 Read Memory and Auto Inc Address
// 10010 Write Memory
// 10011 Write Memory and Auto Inc Address
// 10000 Read Memory
// 10001 Read Memory and Auto Inc Address
// 10010 Write Memory
// 10011 Write Memory and Auto Inc Address
// 1x1xx Unused
// 11xxx Unused

#define CMD_SINGLE_ENABLE 0x00
#define CMD_BRKPT_ENABLE  0x02
#define CMD_LOAD_BRKPT    0x04
#define CMD_RESET         0x06
#define CMD_STEP          0x08
#define CMD_WATCH_READ    0x09
#define CMD_FIFO_RST      0x0A
#define CMD_LOAD_MEM      0x0C
#define CMD_RD_MEM        0x10
#define CMD_RD_MEM_INC    0x11
#define CMD_WR_MEM        0x12
#define CMD_WR_MEM_INC    0x13
#define CMD_RD_IO         0x14
#define CMD_RD_IO_INC     0x15
#define CMD_WR_IO         0x16
#define CMD_WR_IO_INC     0x17

/********************************************************
 * AVR Status Register Definitions
 ********************************************************/

// The status register shares the same port as the mux select register
// Bits 5..0 are the mux select bits (outputs)
// Bits 7..6 are the status bist (inputs)

#define STATUS_PORT       PORTD
#define STATUS_DDR        DDRD
#define STATUS_DIN        PIND

// This bit indicates the interrupt button on the hardware has been pressed
#define INTERRUPTED_MASK  0x40

// This bit indicates the hardware FIFO contains data
// which will be either a watch or a breakpoint event
#define BW_ACTIVE_MASK    0x80

/********************************************************
 * AVR MUX Select Register Definitions
 ********************************************************/

// The mux select register shares the same port as the status register
// This register controls what data is visible through the mux data register
// Bits 5..0 are the mux select bits (outputs)
// Bits 7..6 are the status bist (inputs)

#define MUXSEL_PORT       PORTD
#define MUXSEL_MASK       0x3F
#define MUXSEL_BIT        0

// Additional hardware registers defined below are accessed by writing the offset
// to the MUX Select register, waiting a couple of microseconds, then reading
// the MUX Data register

// Offsets 0-15 are defined below
// Offsets 16-31 are used to return the processor registers

// Instruction Address register: address of the last executed instruction
#define OFFSET_IAL        0
#define OFFSET_IAH        1

// Data register: Memory and IO read/write commands return data via this register
#define OFFSET_DATA       2

// Cycle count register: a 24 bit register that runs while the CPU is running
// this gives visibility of how long (in cycles) each instruction takes
#define OFFSET_CNTH       3
#define OFFSET_CNTL       4
#define OFFSET_CNTM       5

// Watch/Breakpoint Event FIFO
//
// Watch and breakpoint events are queued in a 512 (deep) x 72 (wide) FIFO
//
// Status register BW_ACTIVE indicates the FIFO is non empty.  There is currently
// no indication if events are lost due overflow.
//
// The CMD_WATCH_READ command reads the next word from this FIFO.
//
// The following 9 register provide read access to the word at the head of the
// FIFO, i.e. the FIFO is write-through:

// Instruction address of the watch/breakpoint
#define OFFSET_BW_IAL     6
#define OFFSET_BW_IAH     7

// IO or Memory Read/write address of the watch/breakpoint
#define OFFSET_BW_BAL     8
#define OFFSET_BW_BAH     9

// IO or Memory Read/write data of the watch/breakpoint
#define OFFSET_BW_BD      10

// Type of event, see the watch/breakpoint modes below
// Only bits 0-3 are currently used
#define OFFSET_BW_M       11

// Cycle count at the start of the instruction that caused the event
#define OFFSET_BW_CNTL    12
#define OFFSET_BW_CNTM    13
#define OFFSET_BW_CNTH    14

// Offset 15 is currently unused

/********************************************************
 * AVR MUX Data Register Definitions
 ********************************************************/

// The mux data register is used for reading back the 8-bit register
// addressed by the mux select register.

// This port is input only
#define MUX_PORT          PORTE
#define MUX_DDR           DDRE
#define MUX_DIN           PINE

/********************************************************
 * Watch/Breakpoint Definitions
 ********************************************************/

// The space available for address comparators depends on the size of the CPU core
#if (CPU == Z80)
#define MAXBKPTS 4
#else
#define MAXBKPTS 8
#endif

// The current number of watches/breakpoints
int numbkpts = 0;

// Watches/Breakpoints are loaded into a massive shift register by the
// continue command. The following variables in the AVR track what the
// user has requested. These are updated by the watch/break/clear/trigger
// commands.

// Each watch/breakpoint is defined with 46 bits in the shift register
// MS Bit ............................................ LS Bit
// <Trigger:4> <Mode:10> <Address Mask:16> <Address Value:16>

// A 16 bit breakpoint address
unsigned int breakpoints[MAXBKPTS];

// A 16 bit breakpoint address mask
unsigned int       masks[MAXBKPTS];

// The type (aka mode) of breakpoint (a 10 bit values), allowing
// multiple types to be defined. The bits correspond to the mode
// definitions below.
unsigned int       modes[MAXBKPTS];

// The number of different watch/breakpoint modes
#define NUM_MODES   10

// The following watch/breakpoint modes are defined
#define BRKPT_MEM_READ  0
#define WATCH_MEM_READ  1
#define BRKPT_MEM_WRITE 2
#define WATCH_MEM_WRITE 3
#define BRKPT_IO_READ   4
#define WATCH_IO_READ   5
#define BRKPT_IO_WRITE  6
#define WATCH_IO_WRITE  7
#define BRKPT_EXEC      8
#define WATCH_EXEC      9

// Breakpoint Mode Strings, should match the modes above
char *modeStrings[NUM_MODES] = {
  "Mem Rd Brkpt",
  "Mem Rd Watch",
  "Mem Wr Brkpt",
  "Mem Wr Watch",
  "IO Rd Brkpt",
  "IO Rd Watch",
  "IO Wr Brkpt",
  "IO Wr Watch",
  "Ex Brkpt",
  "Ex Watch"
};

// For convenience, several masks are defined that group similar types of breakpoint/watch

// Mask for all breakpoint types
#define B_MASK       ((1<<BRKPT_MEM_READ) | (1<<BRKPT_MEM_WRITE) | (1<<BRKPT_IO_READ) | (1<<BRKPT_IO_WRITE) | (1<<BRKPT_EXEC))

// Mask for all watch types
#define W_MASK       ((1<<WATCH_MEM_READ) | (1<<WATCH_MEM_WRITE) | (1<<WATCH_IO_READ) | (1<<WATCH_IO_WRITE) | (1<<WATCH_EXEC))

// Mask for all breakpoints/watches that read memory or IO
#define BW_RD_MASK   ((1<<BRKPT_MEM_READ) | (1<<WATCH_MEM_READ) | (1<<BRKPT_IO_READ) | (1<<WATCH_IO_READ))

// Mask for all breakpoints/watches that write memory or IO
#define BW_WR_MASK   ((1<<BRKPT_MEM_WRITE) | (1<<WATCH_MEM_WRITE) | (1<<BRKPT_IO_WRITE) | (1<<WATCH_IO_WRITE))

// Mask for all breakpoint or watches that read/write Memory or IO
#define BW_RDWR_MASK (BW_RD_MASK | BW_WR_MASK)

// Mask for all breakpoints that read/write Memory or IO
#define B_RDWR_MASK  (BW_RDWR_MASK & B_MASK)

/********************************************************
 * External Trigger definitions
 ********************************************************/

// A boolean function of the external trigger inputs that
// is used to gate the watch/breakpoint.
int             triggers[MAXBKPTS];

#define NUM_TRIGGERS 16

char * triggerStrings[NUM_TRIGGERS] = {
  "Never",
  "~T0 and ~T1",
  "T0 and ~T1",
  "~T1",
  "~T0 and T1",
  "~T0",
  "T0 xor T1",
  "~T0 or ~T1",
  "T0 and T1",
  "T0 xnor T1",
  "T0",
  "T0 or ~T1",
  "T1",
  "~T0 or T1",
  "T0 or T1",
  "Always",
};

#define TRIGGER_ALWAYS 15

/********************************************************
 * Other global variables
 ********************************************************/

// The current memory address (e.g. used when disassembling)
unsigned int memAddr = 0;

// When single stepping, trace (i.e. log) event N instructions
// Setting this to 0 will disable logging
long trace;


/********************************************************
 * User Command Processor
 ********************************************************/

void readCmd(char *cmd) {
  char c;
  int i = 0;
  log0(">> ");
  while (1) {
    c = Serial_RxByte0();
    if (c == 8) {
      // Handle backspace/delete
      if (i > 0) {
        i--;
        Serial_TxByte0(c);
        Serial_TxByte0(32);
        Serial_TxByte0(c);
      }
    } else if (c == 13) {
      // Handle return
      if (i == 0) {
        while (cmd[i]) {
          Serial_TxByte0(cmd[i++]);
        }
      } else {
        cmd[i] = 0;
      }
      Serial_TxByte0(10);
      Serial_TxByte0(13);
      return;
    } else if (c >= 32) {
      // Handle any other non-control character
      Serial_TxByte0(c);
      cmd[i] = c;
      i++;
    }
  }
}

/********************************************************
 * Low-level hardware commands
 ********************************************************/

// Send a single hardware command
void hwCmd(unsigned int cmd, unsigned int param) {
  cmd |= param;
  CTRL_PORT &= ~CMD_MASK;
  CTRL_PORT |= cmd;
  Delay_us(2);
  CTRL_PORT |= CMD_EDGE;
  Delay_us(2);
}

// Read an 8-bit register via the Mux
unsigned int hwRead8(unsigned int offset) {
  MUXSEL_PORT &= ~MUXSEL_MASK;
  MUXSEL_PORT |= offset << MUXSEL_BIT;
  Delay_us(1);
  return MUX_DIN;
}

// Read an 16-bit register via the Mux
unsigned int hwRead16(unsigned int offset) {
  unsigned int lsb;
  MUXSEL_PORT &= ~MUXSEL_MASK;
  MUXSEL_PORT |= offset << MUXSEL_BIT;
  Delay_us(1);
  lsb = MUX_DIN;
  MUXSEL_PORT |= 1 << MUXSEL_BIT;
  Delay_us(1);
  return (MUX_DIN << 8) | lsb;
}

// Shift a breakpoint definition into the breakpoint shift register

void shift(unsigned int value, int numbits) {
  while (numbits-- > 0) {
    hwCmd(CMD_LOAD_BRKPT, value & 1);
    value >>= 1;
  }
}

void shiftBreakpointRegister(unsigned int addr, unsigned int mask, unsigned int mode, int trigger) {
  shift(addr, 16);
  shift(mask, 16);
  shift(mode, 10);
  shift(trigger, 4);
}

#ifdef LCD
//  LCD support code (will be depricated soon)
void lcdAddr(unsigned int addr) {
  int i;
  int nibble;
  lcd_goto(6);
  // Avoid using sprintf, as it adds quite a lot of code
  for (i = 3; i >= 0; i--) {
    nibble = addr >> (i * 4);
    nibble &= 0x0F;
    nibble += '0';
    if (nibble > '9') {
      nibble += 'A' - '9' - 1;
    }
    lcd_putc(nibble);
  }
}
#endif

/********************************************************
 * Host Memory/IO Access helpers
 ********************************************************/

#ifdef CPUEMBEDDED
void loadData(unsigned int data) {
  int i;
  for (i = 0; i <= 7; i++) {
    hwCmd(CMD_LOAD_MEM, data & 1);
    data >>= 1;
  }
}

void loadAddr(unsigned int addr) {
  int i;
  for (i = 0; i <= 15; i++) {
    hwCmd(CMD_LOAD_MEM, addr & 1);
    addr >>= 1;
  }
}

unsigned int readMemByte() {
  hwCmd(CMD_RD_MEM, 0);
  Delay_us(10);
  return hwRead8(OFFSET_DATA);
}

unsigned int readMemByteInc() {
  hwCmd(CMD_RD_MEM_INC, 0);
  Delay_us(10);
  return hwRead8(OFFSET_DATA);
}

void writeMemByte() {
  hwCmd(CMD_WR_MEM, 0);
}

void writeMemByteInc() {
  hwCmd(CMD_WR_MEM_INC, 0);
}

unsigned int readIOByte() {
  hwCmd(CMD_RD_IO, 0);
  Delay_us(10);
  return hwRead8(OFFSET_DATA);
}

unsigned int readIOByteInc() {
  hwCmd(CMD_RD_IO_INC, 0);
  Delay_us(10);
  return hwRead8(OFFSET_DATA);
}

void writeIOByte() {
  hwCmd(CMD_WR_IO, 0);
}

void writeIOByteInc() {
  hwCmd(CMD_WR_IO_INC, 0);
}

unsigned int disMem(unsigned int addr) {
  loadAddr(addr);
  return disassemble(addr);
}

void genericDump(char *params, unsigned int (*readFunc)()) {
  int i, j;
  unsigned int row[16];
  sscanf(params, "%x", &memAddr);
  loadAddr(memAddr);
  for (i = 0; i < 0x100; i+= 16) {
    for (j = 0; j < 16; j++) {
      row[j] = (*readFunc)();
    }
    log0("%04X ", memAddr + i);
    for (j = 0; j < 16; j++) {
      log0("%02X ", row[j]);
    }
    log0(" ");
    for (j = 0; j < 16; j++) {
      unsigned int c = row[j];
      if (c < 32 || c > 126) {
        c = '.';
      }
      log0("%c", c);
    }
    log0("\n");
  }
  memAddr += 0x100;
}

void genericWrite(char *params, void (*writeFunc)()) {
  unsigned int addr;
  unsigned int data;
  long count = 1;
  sscanf(params, "%x %x %ld", &addr, &data, &count);
  log0("Wr: %04X = %02X\n", addr, data);
  loadData(data);
  loadAddr(addr);
  while (count-- > 0) {
    (*writeFunc)();
  }
}

void genericRead(char *params, unsigned int (*readFunc)()) {
  unsigned int addr;
  unsigned int data;
  unsigned int data2;
  long count = 1;
  sscanf(params, "%x %ld", &addr, &count);
  loadAddr(addr);
  data = (*readFunc)();
  log0("Rd: %04X = %02X\n", addr, data);
  while (count-- > 1) {
    data2 = (*readFunc)();
    if (data2 != data) {
      log0("Inconsistent Rd: %02X <> %02X\n", data2, data);
    }
    data = data2;
  }
}

#endif

/********************************************************
 * Logging Helpers
 ********************************************************/

void logCycleCount(int offsetLow, int offsetHigh) {
  unsigned long count = (((unsigned long) hwRead8(offsetHigh)) << 16) | hwRead16(offsetLow);
  unsigned long countSecs = count / 1000000;
  unsigned long countMicros = count % 1000000;
  log0("%02ld.%06ld: ", countSecs, countMicros);
}

void logMode(unsigned int mode) {
  int i;
  int first = 1;
  for (i = 0; i < NUM_MODES; i++) {
    if (mode & 1) {
      if (!first) {
        log0(", ");
      }
      log0("%s", modeStrings[i]);
      first = 0;
    }
    mode >>= 1;
  }
}

void logTrigger(int trigger) {
  if (trigger >= 0 && trigger < NUM_TRIGGERS) {
    log0("trigger: %s", triggerStrings[trigger]);
  } else {
    log0("trigger: ILLEGAL");
  }
}

int logDetails() {
  unsigned int i_addr = hwRead16(OFFSET_BW_IAL);
  unsigned int b_addr = hwRead16(OFFSET_BW_BAL);
  unsigned int b_data = hwRead8(OFFSET_BW_BD);
  unsigned int mode   = hwRead8(OFFSET_BW_M);
  unsigned int watch  = mode & 1;

  // Convert from 4-bit compressed to 10 bit expanded mode representation
  mode = 1 << mode;

  // Update the serial console
  if (mode & W_MASK) {
    logCycleCount(OFFSET_BW_CNTL, OFFSET_BW_CNTH);
  }
  logMode(mode);
  log0(" hit at %04X", i_addr);
  if (mode & BW_RDWR_MASK) {
    if (mode & BW_WR_MASK) {
      log0(" writing");
    } else {
      log0(" reading");
    }
    log0(" %04X = %02X\n", b_addr, b_data);
  } else {
    log0("\n");
  }
#ifdef CPUEMBEDDED
  if (mode & B_RDWR_MASK) {
    // It's only safe to do this for brkpts, as it makes memory accesses
    logCycleCount(OFFSET_BW_CNTL, OFFSET_BW_CNTH);
    disMem(i_addr);
  }
#endif
  return watch;
}

void logAddr() {
  memAddr = hwRead16(OFFSET_IAL);
  // Update the LCD display
#ifdef LCD
  lcdAddr(memAddr);
#endif
  // Update the serial console
  logCycleCount(OFFSET_CNTL, OFFSET_CNTH);
#ifdef CPUEMBEDDED
  //log0("%04X\n", i_addr);
  disMem(memAddr);
#else
  log0("%04X\n", memAddr);
#endif
  return;
}

void version() {
#ifdef CPUEMBEDDED
  log0("%s In-Circuit Emulator version %s\n", NAME, VERSION);
#else
  log0("%s Bus Monitor version %s\n", NAME, VERSION);
#endif
  log0("Compiled at %s on %s\n",__TIME__,__DATE__);
  log0("%d watches/breakpoints implemented\n",MAXBKPTS);
}

/********************************************************
 * Watch/Breakpoint helpers
 ********************************************************/

// Return the index of a breakpoint from the user specified address
int lookupBreakpoint(char *params) {
  int i;
  int n = -1;
  sscanf(params, "%x", &n);
  // First, look assume n is an address, and try to map to an index
  for (i = 0; i < numbkpts; i++) {
    if (breakpoints[i] == n) {
      n = i;
      break;
    }
  }
  if (n < numbkpts) {
    return n;
  }
  log0("Breakpoint/watch not set at %04X\n", n);
  return -1;
}

// Enable/Disable single stepping
void setSingle(int single) {
  hwCmd(CMD_SINGLE_ENABLE, single ? 1 : 0);
}

// Enable/Disable tracing
void setTrace(long i) {
  trace = i;
  if (trace) {
    log0("Tracing every %ld instructions while single stepping\n", trace);
  } else {
    log0("Tracing disabled\n");
  }
}

// Set the breakpoint state variables
void setBreakpoint(int i, unsigned int addr, unsigned int mask, unsigned int mode, int trigger) {
  logMode(mode);
  log0(" set at %04X\n", addr);
  breakpoints[i] = addr & mask;
  masks[i] = mask;
  modes[i] = mode;
  triggers[i] = trigger;
}

// A generic helper that does most of the work of the watch/breakpoint commands
void genericBreakpoint(char *params, unsigned int mode) {
  int i;
  unsigned int addr;
  unsigned int mask = 0xFFFF;
  int trigger = -1;
  sscanf(params, "%x %x %x", &addr, &mask, &trigger);
  for (i = 0; i < numbkpts; i++) {
    if (breakpoints[i] == addr) {
      if (modes[i] & mode) {
        logMode(mode);
        log0(" already set at %04X\n", addr);
      } else {
        // Preserve the existing trigger, unless it is overridden
        if (trigger == -1) {
          trigger = triggers[i];
        }
        setBreakpoint(i, addr, mask, modes[i] | mode, trigger);
      }
      return;
    }
  }
  if (numbkpts == MAXBKPTS) {
    log0("All %d breakpoints are already set\n", numbkpts);
    return;
  }
  numbkpts++;
  // New breakpoint, so if trigger not specified, set to ALWAYS
  if (trigger == -1) {
    trigger = TRIGGER_ALWAYS;
  }
  for (i = numbkpts - 2; i >= -1; i--) {
    if (i == -1 || breakpoints[i] < addr) {
      setBreakpoint(i + 1, addr, mask, mode, trigger);
      return;
    } else {
      breakpoints[i + 1] = breakpoints[i];
      masks[i + 1] = masks[i];
      modes[i + 1] = modes[i];
      triggers[i + 1] = triggers[i];
    }
  }
}


/********************************************************
 * Test Helpers
 ********************************************************/

#ifdef CPUEMBEDDED
char *testNames[6] = {
  "Fixed",
  "Checkerboard",
  "Inverse checkerboard",
  "Address pattern",
  "Inverse address pattern",
  "Random"
};

unsigned int getData(unsigned int addr, int data) {
  if (data == -1) {
    // checkerboard
    return (addr & 1) ? 0x55 : 0xAA;
  } else if (data == -2) {
    // inverse checkerboard
    return (addr & 1) ? 0xAA : 0x55;
  } else if (data == -3) {
    // address pattern
    return (0xC3 ^ addr ^ (addr >> 8)) & 0xff;
  } else if (data == -4) {
    // address pattern
    return (0x3C ^ addr ^ (addr >> 8)) & 0xff;
  } else if (data < 0) {
    // random data
    return rand() & 0xff;
  } else {
    // fixed data
    return data & 0xff;
  }
}

void test(unsigned int start, unsigned int end, int data) {
  long i;
  int name;
  int actual;
  int expected;
  unsigned int fail = 0;
  // Write
  srand(data);
  for (i = start; i <= end; i++) {
    loadData(getData(i, data));
    loadAddr(i);
    writeMemByteInc();
  }
  // Read
  srand(data);
  loadAddr(start);
  for (i = start; i <= end; i++) {
    actual = readMemByteInc();
    expected = getData(i, data);
    if (expected != actual) {
      log0("Fail at %04lX (Wrote: %02X, Read back %02X)\n", i, expected, actual);
      fail++;
    }
  }
  name = -data;
  if (name < 0) {
    name = 0;
  }
  if (name > 5) {
    name = 5;
  }
  log0("Memory test: %s", testNames[name]);
  if (data >= 0) {
    log0(" %02X", data);
  }
  if (fail) {
    log0(": failed: %d errors\n", fail);
  } else {
    log0(": passed\n");
  }
}
#endif // CPUEMBEDDED

/*******************************************
 * User Commands
 *******************************************/

void doCmdHelp(char *params) {
  int i;
  version();
  log0("Commands:\n");
  for (i = 0; i < NUM_CMDS; i++) {
    log0("    %s\n", cmdStrings[i]);
  }
}

void doCmdStep(char *params) {
  static long instructions = 1;
  long i;
  long j;
  sscanf(params, "%ld", &instructions);
  if (instructions <= 0) {
    log0("Number of instuctions must be positive\n");
    return;
  }

  log0("Stepping %ld instructions\n", instructions);

  j = trace;
  for (i = 1; i <= instructions; i++) {
    // Step the CPU
    hwCmd(CMD_STEP, 0);
    if (i == instructions || (trace && (--j == 0))) {
      Delay_us(10);
      logAddr();
      j = trace;
    }
  }
}

void doCmdReset(char *params) {
  log0("Resetting CPU\n");
#if (CPU == 6502)
  // For the 6502 cores, to get the single stepping to stop correctly
  // on the first instruction after reset, it helps to assert reset twice.
  // I haven't looked into why this is, as it doesn't seem very important.
  // It's mostly cosmetic, but nice on the Atom to consisently show FF3F.
  int i;
  for (i = 0; i < 2; i++) {
#endif
   hwCmd(CMD_RESET, 1);
   Delay_us(50);
   hwCmd(CMD_STEP, 0);
   Delay_us(50);
   hwCmd(CMD_RESET, 0);
   Delay_us(50);
#if (CPU == 6502)
  }
#endif
  logAddr();
}

#ifdef CPUEMBEDDED

// doCmdRegs is now in regs<cpu>.c

void doCmdDis(char *params) {
  int i;
  sscanf(params, "%x", &memAddr);
  loadAddr(memAddr);
  for (i = 0; i < 10; i++) {
    memAddr = disassemble(memAddr);
  }
}

void doCmdFill(char *params) {
  long i;
  unsigned int start;
  unsigned int end;
  unsigned int data;
  sscanf(params, "%x %x %x", &start, &end, &data);
  log0("Wr: %04X to %04X = %02X\n", start, end, data);
  loadData(data);
  loadAddr(start);
  for (i = start; i <= end; i++) {
    writeMemByteInc();
  }
}

void doCmdCrc(char *params) {
  long i;
  int j;
  unsigned int start;
  unsigned int end;
  unsigned int data;
  unsigned long crc = 0;
  sscanf(params, "%x %x", &start, &end);
  loadAddr(start);
  for (i = start; i <= end; i++) {
    data = readMemByteInc();
    for (j = 0; j < 8; j++) {
      crc = crc << 1;
      crc = crc | (data & 1);
      data >>= 1;
      if (crc & 0x10000)
        crc = (crc ^ CRC_POLY) & 0xFFFF;
    }
  }
  log0("crc: %04X\n", crc);
}

void doCmdMem(char *params) {
  genericDump(params, readMemByteInc);
}

void doCmdReadMem(char *params) {
  genericRead(params, readMemByte);
}

void doCmdWriteMem(char *params) {
  genericWrite(params, writeMemByte);
}

#if (CPU == Z80)

void doCmdIO(char *params) {
  genericDump(params, readIOByteInc);
}

void doCmdReadIO(char *params) {
  genericRead(params, readIOByte);
}

void doCmdWriteIO(char *params) {
  genericWrite(params, writeIOByte);
}

#endif

void doCmdTest(char *params) {
  unsigned int start;
  unsigned int end;
  int data =-100;
  int i;
  sscanf(params, "%x %x %d", &start, &end, &data);
  if (data == -100) {
    test(start, end, 0x55);
    test(start, end, 0xAA);
    test(start, end, 0xFF);
    for (i = 0; i >= -7; i--) {
      test(start, end, i);
    }
  } else {
    test(start, end, data);
  }
}

#endif // CPUEMBEDDED

void doCmdTrace(char *params) {
  long i;
  sscanf(params, "%ld", &i);
  setTrace(i);
}

void doCmdList(char *params) {
  int i;
  if (numbkpts) {
    for (i = 0; i < numbkpts; i++) {
      log0("%d: %04X mask %04X: ", i, breakpoints[i], masks[i]);
      logMode(modes[i]);
      log0(" (");
      logTrigger(triggers[i]);
      log0(")\n");
    }
  } else {
      log0("No breakpoints set\n");
  }
}

void doCmdBreakI(char *params) {
  genericBreakpoint(params, 1 << BRKPT_EXEC);
}

void doCmdWatchI(char *params) {
  genericBreakpoint(params, 1 << WATCH_EXEC);
}

void doCmdBreakRdMem(char *params) {
  genericBreakpoint(params, 1 << BRKPT_MEM_READ);
}

void doCmdWatchRdMem(char *params) {
  genericBreakpoint(params, 1 << WATCH_MEM_READ);
}

void doCmdBreakWrMem(char *params) {
  genericBreakpoint(params, 1 << BRKPT_MEM_WRITE);
}

void doCmdWatchWrMem(char *params) {
  genericBreakpoint(params, 1 << WATCH_MEM_WRITE);
}

#if (CPU == Z80)

void doCmdBreakRdIO(char *params) {
  genericBreakpoint(params, 1 << BRKPT_IO_READ);
}

void doCmdWatchRdIO(char *params) {
  genericBreakpoint(params, 1 << WATCH_IO_READ);
}

void doCmdBreakWrIO(char *params) {
  genericBreakpoint(params, 1 << BRKPT_IO_WRITE);
}

void doCmdWatchWrIO(char *params) {
  genericBreakpoint(params, 1 << WATCH_IO_WRITE);
}

#endif

void doCmdClear(char *params) {
  int i;
  int n = lookupBreakpoint(params);
  if (n < 0) {
    return;
  }
  log0("Removing ");
  logMode(modes[n]);
  log0(" at %04X\n", breakpoints[n]);
  for (i = n; i < numbkpts; i++) {
    breakpoints[i] = breakpoints[i + 1];
    masks[i] = masks[i + 1];
    modes[i] = modes[i + 1];
    triggers[i] = triggers[i + 1];
  }
  numbkpts--;
}

void doCmdTrigger(char *params) {
  int trigger = -1;
  int n = lookupBreakpoint(params);
  if (n < 0) {
    log0("Trigger Codes:\n");
    for (trigger = 0; trigger < NUM_TRIGGERS; trigger++) {
      log0("    %X = %s\n", trigger, triggerStrings[trigger]);
    }
    return;
  }
  sscanf(params, "%*x %x", &trigger);
  if (trigger >= 0 && trigger < NUM_TRIGGERS) {
    triggers[n] = trigger;
  } else {
    log0("Illegal trigger code (see help for trigger codes)\n");
  }
}

void doCmdContinue(char *params) {
  int i;
  int status;
#ifdef LCD
  unsigned int i_addr;
#endif
  int reset = 0;
  sscanf(params, "%d", &reset);

  // Disable breakpoints to allow loading
  hwCmd(CMD_BRKPT_ENABLE, 0);

  // Load breakpoints into comparators
  for (i = 0; i < numbkpts; i++) {
    shiftBreakpointRegister(breakpoints[i], masks[i], modes[i], triggers[i]);
  }
  for (i = numbkpts; i < MAXBKPTS; i++) {
    shiftBreakpointRegister(0, 0, 0, 0);
  }

  // Step the 6502, otherwise the breakpoint happends again immediately
  hwCmd(CMD_STEP, 0);

  // Enable breakpoints
  hwCmd(CMD_BRKPT_ENABLE, 1);

  // Disable single stepping
  setSingle(0);

  // Reset if required
  if (reset) {
    log0("Resetting CPU\n");
    hwCmd(CMD_RESET, 1);
    Delay_us(100);
    hwCmd(CMD_RESET, 0);
  }

  // Wait for breakpoint to become active
  log0("CPU free running...\n");
  int cont = 1;
  do {
    // Update the LCD display
#ifdef LCD
    i_addr = hwRead16(OFFSET_IAL);
    lcdAddr(i_addr);
#endif

    status = STATUS_DIN;
    if (status & BW_ACTIVE_MASK) {
      cont = logDetails();
      hwCmd(CMD_WATCH_READ, 0);
    }
    if (status & INTERRUPTED_MASK) {
      cont = 0;
    }
    if (Serial_ByteRecieved0()) {
       // Interrupt on a return, ignore other characters
       if (Serial_RxByte0() == 13) {
          cont = 0;
       }
    }
    Delay_us(10);
  } while (cont);
  log0("Interrupted\n");

  // Enable single stepping
  setSingle(1);

  // Disable breakpoints
  hwCmd(CMD_BRKPT_ENABLE, 0);

  // Show current instruction
  logAddr();
}

void initialize() {
  CTRL_DDR = 255;
  STATUS_DDR = MUXSEL_MASK;
  MUX_DDR = 0;
  CTRL_PORT = 0;
  Serial_Init(57600,57600);
#ifdef LCD
  lcd_init();
  lcd_puts("Addr: xxxx");
#endif
  version();
  hwCmd(CMD_RESET, 0);
  hwCmd(CMD_FIFO_RST, 0);
  setSingle(1);
  setTrace(1);
}

void dispatchCmd(char *cmd) {
  int i;
  char *cmdString;
  int minLen;
  int cmdStringLen;
  int cmdLen = 0;
  while (cmd[cmdLen] >= 'a' && cmd[cmdLen] <= 'z') {
    cmdLen++;
  }
  for (i = 0; i < NUM_CMDS; i++) {
    cmdString = cmdStrings[i];
    cmdStringLen = strlen(cmdString);
    minLen = cmdLen < cmdStringLen ? cmdLen : cmdStringLen;
    if (strncmp(cmdString, cmd, minLen) == 0) {
      (*cmdFuncs[i])(cmd + cmdLen);
      return;
    }
  }
  log0("Unknown command %s\n", cmd);
}

int main(void) {
  static char command[32];
  initialize();
  doCmdContinue(NULL);
  while (1) {
    readCmd(command);
    dispatchCmd(command);
  }
  return 0;
}