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main.c
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main.c
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// Monitor program for 68008 Microprocessor Kit V1.0
// (C) 2016 Wichit Sirichote
// CPU: Motorola 68008P10 10MHz oscillator
// 128 kB RAM, 128kB ROM
// 0x00000-0x1FFFF is RAM space
// 0x40000-0x5FFFF is ROM space
// SSP and boot vector are stored at location 0-7 in ROM.
// trap #0 is for monitor return from user code.
// Serial port is 2400 bit/s 8n1.
// Hex files for downloading accept S1 and S2, 16-bit address and 24-bit address
// Development Tool: IDE68k v3.0
// project files include
// cswitches.a68
// mycstart.asm
// mycode.asm
// lcd.c
// main.c
///////////////////////////////////////////////////////////
// Modified 2/25/2017 Keith R. Hacke [email protected]
// Added code for software UART to speeds up to 9600 Baud
// * Changed delay_bit and delay_15bit to use variable
// so we can tweak them to get to 9600 Baud
// * Tested with Tera Term Pro version 2.3
// Baud:9600 Data:8 bit Parity:None Stop:1 bit Flow Control:none
// * For testing, seems to work best when in RAM if ide86
// C compiler set to "Small Code" in memory model settings
// * Make sure your ide68k project has files in this order:
// cswitches.a68
// mycstart.asm
// main.c
// mycode.asm
// lcd.c
// For whatever reason, the order seems to matter if you
// want to get the Mon program running in RAM (for testing)
// Not sure if it matters in EPROM.
//////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////
// Extended 2021-04-08 V 4.4 Fred Bayer [email protected]
//
// * Code cleanup and several bug fixes
// * Provide fixed entries to monitor routines
// * header/include files to call those routines from C or ASM
// * Create a crude font for LED display
// * Define custom chars on LCD
// * Add disassembler
// * Exception handlers
// * TRAP #1 for switchable breakpoints
// * Make user register editable
// * Dump registers and disassembly to serial
// * Memory layout optimized
//
// V 4.5 news:
//
// * Step over subroutine calls and traps
// * 8 and 16 bit offset calculation
// * REG COPY to toggle TRAP #1 breakpoints
// * Message when starting from odd PC
// * more comments
// * disassembler syntax fixes
// * Display target of address register
// * Edit parts of data register
//
// V 4.6 news:
//
// * Step out of a subroutine
// * New display format for status register
// * Variable LCD size
// * LCD present flag
// * Variable shift amount with INS and DEL
//
// V 4.7 news: 2022-02-05
//
// * dynamic breakpoints
// * cleanup monitor states and function names
// * fix disasm TRAP bug
// * go in stepping mode
//
// V 4.8 news: 2022-09-17
//
// * cleanup project structure
// * chase pointers in memory
//
//////////////////////////////////////////////////////////
typedef unsigned char uchar;
typedef unsigned short ushort;
typedef unsigned int uint;
typedef unsigned long ulong;
// Assembler function prototypes
void go(void);
void step_into(void);
void step_over(void);
void step_cont(void);
void step_out(void);
void step_then_go(void);
void disarm_breakpoints(void);
void enable_level2(void);
// C function prototypes
void InitLcd(void);
char *Puts(char *str);
void clr_screen(void);
void goto_xy(int x,int y);
void send_long_hex(ulong n);
void read_memory(void);
void key_data(void);
void pstring(char *s);
void disassemble(ushort** addr, char* dest);
void disassemble_lcd(void);
ushort *dump_disassembly(ushort* addr);
void print_led(int offset, const char* text);
void display_register(ulong *reg);
void dot_register(void);
void format_sr(void);
void newline(void);
int breakpoint_at(ulong address);
// Symbolic constants
#define VERSION "V4.8"
#define INIT_SSP 0x20000
#define INIT_USP 0x1fc00
#define INIT_PC 0x00400
#define INIT_SR 0x2700
#define MAX_BP 8
// Monitor states
#define STATE_AFTER_RESET 0
#define STATE_INPUT_ADDR 1
#define STATE_INPUT_DATA 2
#define STATE_SHIFT 3
#define STATE_COMP_OFFSET 5
#define STATE_COPY_START 10
#define STATE_COPY_END 11
#define STATE_COPY_DEST 12
#define STATE_INPUT_REGISTER 13
#define STATE_SHOW_REGISTER 14
#define STATE_TOGGLE_TRAP1 15
// 68008 kit I/O locations
char *const gpio1 = (char *) 0xF0000; // 8-bit debugging LED
char *const port0 = (char *) 0x80000; // key input
char *const port1 = (char *) 0x80002; // digit driver
char *const port2 = (char *) 0xA0000; // segment driver
// Bit patterns for LED segments
char const convert[]= {
0xBD, 0x30, 0x9B, 0xBA, 0x36, 0xAE, 0xAF, 0x38, 0xBF, 0xBE, // 0123456789
0x3F, 0xA7, 0x8D, 0xB3, 0x8F, 0x0F, 0xAD, 0x37, 0x20, 0xB1, // AbCdEFGhiJ
0x97, 0x85, 0x29, 0x23, 0xA3, 0x1F, 0x3E, 0x03, 0xAE, 0x87, // KLMnoPqrSt
0xB5, 0xA1, 0x94, 0x8A, 0xB6, 0x9B, // UvWXyZ
0x8D, 0x26, 0xB8, 0x1C, 0x80 // [\]^_
};
// Segments bit numbers
// .-3-.
// 2 4
// .-1-.
// 0 5
// .-7-.*6
#define LED_SEG_POINT 0x40
#define LED_SEG_MINUS 0x02
#define LED_SEG_BREAK 0x1e
// Magic value to distinguish Kit from emulator and
// to avoid re-init globals after reset.
#define MAGIC 0x1138
/////////////////////////////////////////////////////////////////////////////////
// Global variables
// !!! Don't add variables here or change their order, always add them at the
// !!! end marked below. This ensures that the addresses listed in the monitor
// !!! include files don't change. You have about 260 additonal bytes available
// !!! in memory below 0x00400
/////////////////////////////////////////////////////////////////////////////////
ushort magic; // to init certain variables only on power up
char led_buffer[8]; // display buffer
char line[81]; // output line buffer
char exception_nr;
char state;
char entry_started;
char beep_flag;
char hit_a6;
char key;
ulong tick;
ushort disasm_lines; // how many lines to disassemble
ushort hexdump_lines; // how many (16 byte) lines of memory to display
char disasm_on_lcd; // flag to enable displaying disassembly on LCD
char enable_trap1; // 1 -> TRAP #1 stops program, 0 -> TRAP #1 is ignored
// delay counters
int glob_d;
uint glob_j;
uint glob_b1; // Counter for delay_bit
uint glob_b2; // Counter for delay_15bit
uchar glob_n;
char glob_i;
char bcc_error; // flag for checking bcc error
char bcc;
char save_bcc;
ulong start, end;
ulong display_PC, save_PC;
ushort *curr_inst, *next_inst;
// User registers
ulong user_data[8]; // D0-D7
ulong user_addr[7]; // A0-A6
ulong user_usp; // USP
ulong user_ssp; // SSP
ushort user_sr; // SR
ulong user_pc; // PC
ulong *edit_register; // register being edited
// new in 4.5
ulong call_frame; // SP limit for stepping over
char frame_origin; // 0 if SP limit is from SSP, other from USP
char show_sr; // status register display: 0 classic, 1 numeric, 2 symbolic
uchar edit_size; // size of data register being edited, 1, 2 or 4
// new in 4.6
char step_mode; // 0 for step over, 1 for step out
uchar lcd_width; // width of lcd in chars, typical 8, 16 or 20
uchar lcd_lines; // number of lines in LCD, typical 1, 2 or 4
char lcd_present; // 0 if missing, non-zero if present
ushort shift_size; // number of bytes to shift with INS and DEL
// new in 4.7
short num_bp; // number of active breakpoints
char bp_armed; // breakpoints armed
ulong break_points[MAX_BP]; // addresses of breakpoints
ushort orig_instr[MAX_BP]; // original instructions
/////////////////////////////////////////////////////////////////////////////////
// !! Current end of global variables, you can add more here.
/////////////////////////////////////////////////////////////////////////////////
//////////////////////////// Software UART 9600 bit/s /////////////////////////////////////////
void delay_bit(void)
{
for (glob_j=0; glob_j<glob_b1; glob_j++)
continue;
glob_d = 0; // Tune for 9600 Baud
glob_d = 0;
glob_d = 0;
// Note d=d+1 too slow in EPROM (may be ERPOM slower than RAM??)
glob_d = 0;
}
void delay_15bit(void)
{
for (glob_j=0; glob_j<glob_b2; glob_j++)
continue;
glob_d=0;
}
void send_byte(char n)
{
*port1 = 0x7f; // send start bit
delay_bit();
for (glob_i=0; glob_i<8; glob_i++) {
if (n&1)
*port1 = 0xff;
else
*port1 = 0x7f;
delay_bit();
n >>= 1;
}
*port1 = 0xff; // send stop bit
delay_bit();
}
char get_byte(void)
{
glob_n = 0;
while (*port0&0x80)
continue; // wait for start bit
delay_15bit(); // must be 1.5 bit
for (glob_i=0; glob_i<7; glob_i++) {
if ((*port0&0x80)!=0)
glob_n |= 0x80;
glob_n >>= 1;
delay_bit();
}
delay_bit(); // center bit of D7
return glob_n; // rest is for monitor processing half of D7+full period of stop bit
}
// c must be 0-9 and A-F for hex digit
uchar nibble2hex(char c)
{
if (c<0x40)
return c-0x30;
else
return c-0x37;
}
uchar gethex(void)
{
char a,b;
a = get_byte();
b = get_byte();
a = nibble2hex(a)<<4;
b = nibble2hex(b);
a |= b;
bcc += a; // compute check sum
return a;
}
ulong get24bitaddress(void)
{
ulong load_address;
load_address = 0;
load_address |= gethex();
load_address <<= 8;
load_address |= gethex();
load_address <<= 8;
load_address |= gethex();
return load_address;
}
ulong get16bitaddress(void)
{
ulong load_address;
load_address = 0;
load_address |= gethex();
load_address <<= 8;
load_address |= gethex();
return load_address;
}
void read_record1(void)
{
char i, byte_count;
long address24bit;
char *sload;
bcc = 0;
byte_count = gethex()-3; // byte count only for data byte
address24bit = get16bitaddress();
sload = address24bit;
for (i=0; i<byte_count; i++)
*(sload+i) = gethex();
bcc = ~bcc; // one's complement
*gpio1 = bcc; // loading indicator
save_bcc = bcc;
if (save_bcc != gethex())
bcc_error = 1;
}
void read_record2(void)
{
char i, byte_count;
long address24bit;
char* sload;
bcc = 0;
byte_count = gethex()-4; // byte count only for data byte
address24bit = get24bitaddress();
sload = address24bit;
for (i=0; i<byte_count; i++)
*(sload+i) = gethex();
bcc = ~bcc; // one's complement
*gpio1 = bcc; // loading indicator
save_bcc = bcc;
if (save_bcc != gethex())
bcc_error=1;
}
void get_s_record(void)
{
char end = 0;
bcc_error = 0;
while (end==0)
{
while (get_byte() != 'S')
continue;
switch(get_byte()) // get record type
{
case '0': end=0; break;
case '1': read_record1(); break;
case '2': read_record2(); break;
case '8': end=1; break;
case '9': end=1; break;
}
}
if (bcc_error)
pstring("\r\ncheck sum errors!\r\n");
else
pstring("\r\nload successfull!\r\n");
curr_inst = display_PC;
key_data();
}
void send_hex(char n)
{
char k;
k = n>>4;
k = k&0xf;
if (k>9)
send_byte(k+0x37);
else
send_byte(k+0x30);
k = n&0xf;
if (k>9)
send_byte(k+0x37);
else
send_byte(k+0x30);
}
void send_word_hex(ushort n)
{
send_hex((n>>8)&0xff);
send_hex(n&0xff);
}
void send_long_hex(ulong n)
{
send_hex((n>>24)&0xff);
send_hex((n>>16)&0xff);
send_hex((n>>8)&0xff);
send_hex(n&0xff);
}
// print string to terminal
void pstring(char *s)
{
while (*s)
send_byte(*s++);
}
////////////////////////////////// end of Software UART ////////////////////////////
//--------------------------produce beep when key presed ----------------------
void delay_beep(void)
{
char j;
for (j=0; j<0x14; j++)
continue;
}
void beep(void)
{
*port2=0; // turn off display
for (glob_d=0; glob_d<80; glob_d++) {
*port1 = ~0x40;
delay_beep();
*port1 = 0xff;
delay_beep();
}
}
//---------------------------- end of beep -------------------------------------
void delay_on(void)
{
for (glob_d=0; glob_d<1; glob_d++)
continue;
}
void delay_off(void)
{
for (glob_d=0; glob_d<10; glob_d++)
continue;
}
char scan(void)
{
char k = 0xf0;
uchar n;
char i,o;
char u = 0;
char q = 0; // key code
key = -1; // if no key pressed key=-1
for (i=0; i<8; i++) {
*port1 = k; // write digit and turn off speaker & TXD
*port2 = led_buffer[i]; // write segment
delay_on();
*port2 = 0; // turn off display
delay_off();
o = *port0; // read key switch
for (n=0; n<6; n++) {// check for 6 rows
if ((o&1)==0)
key=q; // save key if pressed
else
q++;
o >>= 1;
}
k++;
}
return key; // return scan code
}
void delay(int n)
{
int u;
for (u=0; u<n; u++)
continue;
}
void address_display(void)
{
char k;
ulong addr = display_PC;
for (k=3; k<8; ++k) {
led_buffer[k] = convert[addr&0xf];
addr >>= 4;
}
}
void data_display(void)
{
char* dptr = display_PC;
uchar n = *dptr;
led_buffer[0] = convert[n&0xf];
n >>= 4;
led_buffer[1] = convert[n&0xf];
}
void read_memory(void)
{
address_display();
data_display();
led_buffer[2] = breakpoint_at(display_PC) ? LED_SEG_BREAK : 0;
disassemble_lcd();
}
void dot_led(short lower, short upper)
{
// switch on dots in LED from lower (incl.) to upper (excl.), counted from right
short k;
for (k=0; k<lower; ++k)
led_buffer[k] &= ~LED_SEG_POINT;
for (k=lower; k<upper; ++k)
led_buffer[k] |= LED_SEG_POINT;
for (k=upper; k<8; ++k)
led_buffer[k] &= ~LED_SEG_POINT;
}
void dot_address(void)
{
dot_led(3,8);
}
void dot_data(void)
{
dot_led(0,2);
}
void dot_register(void)
{
dot_led(0,2*edit_size);
}
void key_address(void)
{
read_memory();
dot_address();
entry_started = 0;
curr_inst = display_PC;
disassemble_lcd();
state = STATE_INPUT_ADDR;
}
void key_data(void)
{
read_memory();
dot_data();
entry_started = 0;
state = STATE_INPUT_DATA;
}
void start_edit_reg(void)
{
if (edit_register != 0) {
edit_size = 4;
display_register(edit_register);
dot_register();
entry_started = 0;
state = STATE_INPUT_REGISTER;
}
}
void change_edit_size(void) {
if (edit_register != 0 &&
!entry_started &&
edit_register < user_addr) {
switch (edit_size) {
case 4: edit_size = 2; break;
case 2: edit_size = 1; break;
case 1: edit_size = 4; break;
}
dot_register();
}
}
void key_plus(void)
{
if (state==STATE_COPY_START) {
start = display_PC;
print_led(7,"E");
state = STATE_COPY_END;
entry_started = 0;
}
else if (state==STATE_COPY_END) {
end = display_PC;
print_led(7,"d");
state = STATE_COPY_DEST;
entry_started = 0;
}
else if (state==STATE_SHIFT) {
newline();
}
else if (state==STATE_INPUT_ADDR ||
state==STATE_INPUT_DATA ||
state==STATE_COMP_OFFSET) {
display_PC++;
if (display_PC >= next_inst)
curr_inst = display_PC;
read_memory();
key_data();
}
}
void key_minus(void)
{
if (state==STATE_INPUT_ADDR ||
state==STATE_INPUT_DATA ||
state==STATE_COMP_OFFSET) {
display_PC--;
if (display_PC < curr_inst)
curr_inst = display_PC;
read_memory();
key_data();
}
}
void address_hex(void)
{
if (!entry_started)
display_PC = 0;
entry_started = 1;
display_PC <<= 4;
display_PC |= key;
curr_inst = display_PC;
read_memory();
dot_address();
}
void data_hex(void)
{
char* dptr = display_PC;
uchar n = *dptr;
if (!entry_started)
n=0;
entry_started = 1;
n <<= 4;
n |= key;
*dptr = n;
if (n != *dptr) // Data stored doesn't read back the same, ignore it.
;
read_memory();
dot_data();
}
void reg_hex(void)
{
uchar *edit_register8;
ushort *edit_register16;
if (edit_register != 0) {
switch (edit_size) {
case 1:
edit_register8 = edit_register;
edit_register8 += 3;
if (!entry_started)
*edit_register8 = 0;
*edit_register8 <<= 4;
*edit_register8 |= key;
break;
case 2:
edit_register16 = edit_register;
edit_register16 += 1;
if (!entry_started)
*edit_register16 = 0;
*edit_register16 <<= 4;
*edit_register16 |= key;
break;
case 4:
if (!entry_started)
*edit_register = 0;
*edit_register <<= 4;
*edit_register |= key;
break;
}
entry_started = 1;
display_register(edit_register);
dot_register();
}
}
void key_PC(void)
{
display_PC = save_PC;
curr_inst = display_PC;
key_data();
}
void long2buffer(ulong n)
{
char k;
for (k=0; k<8; ++k) {
led_buffer[k] = convert[n&0xf];
n >>= 4;
}
}
void display_sr(void)
{
ushort temp = user_sr;
led_buffer[3] = convert[temp&0xf];
temp >>= 4;
led_buffer[4] = convert[temp&0xf];
temp >>= 4;
led_buffer[5] = convert[temp&0xf];
temp >>= 4;
led_buffer[6] = convert[temp&0xf];
led_buffer[7] = 0;
print_led(5," Sr");
}
// XNZVC
void display_ccr(void)
{
ushort temp = user_sr;
led_buffer[3] = (temp&1) ? convert[1] : convert[0]; // carry flag
led_buffer[4] = (temp&2) ? convert[1] : convert[0]; // overflow flag
led_buffer[5] = (temp&4) ? convert[1] : convert[0]; // zero flag
led_buffer[6] = (temp&8) ? convert[1] : convert[0]; // negative flag
led_buffer[7] = (temp&0x10) ? convert[1] : convert[0]; // extend flag
print_led(5," Cr");
}
void display_fmt_sr(void)
{
format_sr();
print_led(0,line);
}
void display_register(ulong *reg)
{
long2buffer(*reg);
edit_register = reg;
}
// SHIFT (REG) key used with hex key 0-f in state STATE_SHIFT or STATE_SHOW_REGISTER
void select_register(void)
{
state = STATE_SHOW_REGISTER;
if (key<8)
display_register(&user_data[key]);
else if (key<14)
display_register(&user_addr[key-8]);
else if (key==14) {
hit_a6 ^= 1;
if (hit_a6) {
switch (show_sr) {
case 0: display_ccr(); break;
case 1: display_sr(); break;
case 2: display_fmt_sr(); break;
}
edit_register = 0; // not editable
}
else
display_register(&user_addr[6]);
}
else { // key==15
if (user_sr & 0x2000)
display_register(&user_ssp);
else
display_register(&user_usp);
}
}
void key_reg(void)
{
print_led(0," SH1Ft ");
state = STATE_SHIFT;
edit_register = 0;
}
// insert byte and shift bytes down
void insert_byte(void)
{
uint j;
char *dptr = display_PC;
for (j=shift_size; j>0; j--)
dptr[j] = dptr[j-1];
dptr[1] = 0; // insert next byte
display_PC++;
if (display_PC >= next_inst)
curr_inst = display_PC;
read_memory();
state = STATE_INPUT_DATA;
dot_data();
}
// delete current byte and shift bytes up
void delete_byte(void)
{
uint j;
char *dptr = display_PC;
for (j=0; j<shift_size; j++)
dptr[j] = dptr[j+1];
read_memory();
state = STATE_INPUT_DATA;
dot_data();
}
void copy_block(void)
{
state = STATE_COPY_START;
address_display();
dot_address();
print_led(5," -S");
entry_started = 0;
}
void word_enter(void)
{
if (!entry_started)
display_PC = 0;
entry_started = 1;
display_PC <<= 4;
display_PC |= key;
address_display();
dot_address();
}
void print_error(void)
{
print_led(0," Err ");
state = STATE_AFTER_RESET;
}
void print_exception(void)
{
print_led(0,"Err ");
switch (exception_nr) {
case 0x2: print_led(4,"bUS "); break;
case 0x3: print_led(4,"Addr"); break;
case 0x4: print_led(4,"1LLE"); break;
case 0x5: print_led(4,"div0"); break;
case 0x6: print_led(4,"Chk "); break;
case 0x7: print_led(4,"trPv"); break;
case 0x8: print_led(4,"Priv"); break;
// 0x9 Trace actually handled
case 0xa: print_led(4,"LinA"); break;
case 0xb: print_led(4,"LinF"); break;
case 0xc: print_led(4,"1ntr"); break;
case 0xd: print_led(4,"trAP"); break;
}
state = STATE_AFTER_RESET;
}
void print_odd_pc(void)
{
print_led(0," odd PC ");
}
// Print text on LED starting at offset. Allowed chars are digits,
// letters (upper and lower), space and minus. If bit 7 of the character
// is set, the decimal point segment of the LED is switched on, too.
void print_led(int offset, const char* text)
{
int i;
for (i=7-offset; *text; --i,++text) {
char c = *text & 0x7f;
if (c == '-')
led_buffer[i] = LED_SEG_MINUS;
else if (c < '0' || c > '9' && c < 'A')
led_buffer[i] = 0; // unimplemented character
else
led_buffer[i] = convert[nibble2hex(c>=0x60 ? c-0x20 : c)];
if (*text & 0x80)
led_buffer[i] |= LED_SEG_POINT;
}
}
void copy_data(void)
{
ulong destination = display_PC;
long temp32 = end-start;
char *dptr2 = start;
char *dptr = destination;
uint j;