// TinyBASIC.cpp : Defines the entry point for the console application.
// Author: Mike Field <hamster@snap.net.nz>
//
// IF testing with Visual C
//#include "stdafx.h"
#define ARDUINO 1
// ASCII Characters
#define CR '\r'
#define NL '\n'
#define TAB '\t'
#define BELL '\b'
#define SPACE ' '
#define CTRLC 0x03
#define CTRLH 0x08
#define CTRLS 0x13
#define CTRLX 0x18
typedef short unsigned LINENUM;
#if ARDUINO
#define ECHO_CHARS 1
#else
#define ECHO_CHARS 0
#endif
static unsigned char program[412];
static unsigned char *txtpos,*list_line;
static unsigned char expression_error;
static unsigned char *tempsp;
/***********************************************************/
// Keyword table and constants - the last character has 0x80 added to it
static unsigned char keywords[] = {
'L','I','S','T'+0x80,
'L','O','A','D'+0x80,
'N','E','W'+0x80,
'R','U','N'+0x80,
'S','A','V','E'+0x80,
'N','E','X','T'+0x80,
'L','E','T'+0x80,
'I','F'+0x80,
'G','O','T','O'+0x80,
'G','O','S','U','B'+0x80,
'R','E','T','U','R','N'+0x80,
'R','E','M'+0x80,
'F','O','R'+0x80,
'I','N','P','U','T'+0x80,
'P','R','I','N','T'+0x80,
'P','O','K','E'+0x80,
'S','T','O','P'+0x80,
'B','Y','E'+0x80,
0
};
#define KW_LIST 0
#define KW_LOAD 1
#define KW_NEW 2
#define KW_RUN 3
#define KW_SAVE 4
#define KW_NEXT 5
#define KW_LET 6
#define KW_IF 7
#define KW_GOTO 8
#define KW_GOSUB 9
#define KW_RETURN 10
#define KW_REM 11
#define KW_FOR 12
#define KW_INPUT 13
#define KW_PRINT 14
#define KW_POKE 15
#define KW_STOP 16
#define KW_BYE 17
#define KW_DEFAULT 18
struct stack_for_frame {
char frame_type;
char for_var;
short int terminal;
short int step;
unsigned char *current_line;
unsigned char *txtpos;
};
struct stack_gosub_frame {
char frame_type;
unsigned char *current_line;
unsigned char *txtpos;
};
static unsigned char func_tab[] = {
'P','E','E','K'+0x80,
'A','B','S'+0x80,
0
};
#define FUNC_PEEK 0
#define FUNC_ABS 1
#define FUNC_UNKNOWN 2
static unsigned char to_tab[] = {
'T','O'+0x80,
0
};
static unsigned char step_tab[] = {
'S','T','E','P'+0x80,
0
};
static unsigned char relop_tab[] = {
'>','='+0x80,
'<','>'+0x80,
'>'+0x80,
'='+0x80,
'<','='+0x80,
'<'+0x80,
0
};
#define RELOP_GE 0
#define RELOP_NE 1
#define RELOP_GT 2
#define RELOP_EQ 3
#define RELOP_LE 4
#define RELOP_LT 5
#define RELOP_UNKNOWN 6
#define STACK_SIZE (sizeof(struct stack_for_frame)*5)
#define VAR_SIZE sizeof(short int) // Size of variables in bytes
static unsigned char *stack_limit;
static unsigned char *program_start;
static unsigned char *program_end;
static unsigned char *stack; // Software stack for things that should go on the CPU stack
static unsigned char *variables_begin;
static unsigned char *current_line;
static unsigned char *sp;
#define STACK_GOSUB_FLAG 'G'
#define STACK_FOR_FLAG 'F'
static unsigned char table_index;
static LINENUM linenum;
static const unsigned char okmsg[] = "OK";
static const unsigned char whatmsg[] = "What? ";
static const unsigned char howmsg[] = "How?";
static const unsigned char sorrymsg[] = "Sorry!";
static const unsigned char initmsg[] = "TinyBasic in C V0.02.";
static const unsigned char memorymsg[] = " bytes free.";
static const unsigned char breakmsg[] = "break!";
static const unsigned char unimplimentedmsg[] = "Unimplemented";
static const unsigned char backspacemsg[] = "\b \b";
static int inchar(void);
static void outchar(unsigned char c);
static void line_terminator(void);
static short int expression(void);
static unsigned char breakcheck(void);
/***************************************************************************/
static void ignore_blanks(void)
{
while(*txtpos == SPACE || *txtpos == TAB)
txtpos++;
}
/***************************************************************************/
static void scantable(unsigned char *table)
{
int i = 0;
table_index = 0;
while(1)
{
// Run out of table entries?
if(table[0] == 0)
return;
// Do we match this character?
if(txtpos[i] == table[0])
{
i++;
table++;
}
else
{
// do we match the last character of keywork (with 0x80 added)? If so, return
if(txtpos[i]+0x80 == table[0])
{
txtpos += i+1; // Advance the pointer to following the keyword
ignore_blanks();
return;
}
// Forward to the end of this keyword
while((table[0] & 0x80) == 0)
table++;
// Now move on to the first character of the next word, and reset the position index
table++;
table_index++;
ignore_blanks();
i = 0;
}
}
}
/***************************************************************************/
static void pushb(unsigned char b)
{
sp--;
*sp = b;
}
/***************************************************************************/
static unsigned char popb()
{
unsigned char b;
b = *sp;
sp++;
return b;
}
/***************************************************************************/
static void printnum(int num)
{
int digits = 0;
if(num < 0)
{
num = -num;
outchar('-');
}
do {
pushb(num%10+'0');
num = num/10;
digits++;
}
while (num > 0);
while(digits > 0)
{
outchar(popb());
digits--;
}
}
/***************************************************************************/
static unsigned short testnum(void)
{
unsigned short num = 0;
ignore_blanks();
while(*txtpos>= '0' && *txtpos <= '9' )
{
// Trap overflows
if(num >= 0xFFFF/10)
{
num = 0xFFFF;
break;
}
num = num *10 + *txtpos - '0';
txtpos++;
}
return num;
}
/***************************************************************************/
static void printmsgNoNL(const unsigned char *msg)
{
while(*msg)
{
outchar(*msg);
msg++;
}
}
/***************************************************************************/
static unsigned char print_quoted_string(void)
{
int i=0;
unsigned char delim = *txtpos;
if(delim != '"' && delim != '\'')
return 0;
txtpos++;
// Check we have a closing delimiter
while(txtpos[i] != delim)
{
if(txtpos[i] == NL)
return 0;
i++;
}
// Print the characters
while(*txtpos != delim)
{
outchar(*txtpos);
txtpos++;
}
txtpos++; // Skip over the last delimiter
return 1;
}
/***************************************************************************/
static void printmsg(const unsigned char *msg)
{
printmsgNoNL(msg);
line_terminator();
}
/***************************************************************************/
static void getln(char prompt)
{
outchar(prompt);
txtpos = program_end+sizeof(LINENUM);
while(1)
{
char c = inchar();
switch(c)
{
case NL:
break;
case CR:
line_terminator();
// Terminate all strings with a NL
txtpos[0] = NL;
return;
case CTRLH:
if(txtpos == program_end)
break;
txtpos--;
printmsg(backspacemsg);
break;
default:
// We need to leave at least one space to allow us to shuffle the line into order
if(txtpos == variables_begin-2)
outchar(BELL);
else
{
txtpos[0] = c;
txtpos++;
#if ECHO_CHARS
outchar(c);
#endif
}
}
}
}
/***************************************************************************/
static unsigned char *findline(void)
{
unsigned char *line = program_start;
while(1)
{
if(line == program_end)
return line;
if(((LINENUM *)line)[0] >= linenum)
return line;
// Add the line length onto the current address, to get to the next line;
line += line[sizeof(LINENUM)];
}
}
/***************************************************************************/
static void toUppercaseBuffer(void)
{
unsigned char *c = program_end+sizeof(LINENUM);
unsigned char quote = 0;
while(*c != NL)
{
// Are we in a quoted string?
if(*c == quote)
quote = 0;
else if(*c == '"' || *c == '\'')
quote = *c;
else if(quote == 0 && *c >= 'a' && *c <= 'z')
*c = *c + 'A' - 'a';
c++;
}
}
/***************************************************************************/
void printline()
{
LINENUM line_num;
line_num = *((LINENUM *)(list_line));
list_line += sizeof(LINENUM) + sizeof(char);
// Output the line */
printnum(line_num);
outchar(' ');
while(*list_line != NL)
{
outchar(*list_line);
list_line++;
}
list_line++;
line_terminator();
}
/***************************************************************************/
static short int expr4(void)
{
if(*txtpos == '0')
{
txtpos++;
return 0;
}
if(*txtpos >= '1' && *txtpos <= '9')
{
short int a = 0;
do {
a = a*10 + *txtpos - '0';
txtpos++;
} while(*txtpos >= '0' && *txtpos <= '9');
return a;
}
// Is it a function or variable reference?
if(txtpos[0] >= 'A' && txtpos[0] <= 'Z')
{
short int a;
// Is it a variable reference (single alpha)
if(txtpos[1] < 'A' || txtpos[1] > 'Z')
{
a = ((short int *)variables_begin)[*txtpos - 'A'];
txtpos++;
return a;
}
// Is it a function with a single parameter
scantable(func_tab);
if(table_index == FUNC_UNKNOWN)
goto expr4_error;
unsigned char f = table_index;
if(*txtpos != '(')
goto expr4_error;
txtpos++;
a = expression();
if(*txtpos != ')')
goto expr4_error;
txtpos++;
switch(f)
{
case FUNC_PEEK:
return program[a];
case FUNC_ABS:
if(a < 0)
return -a;
return a;
}
}
if(*txtpos == '(')
{
short int a;
txtpos++;
a = expression();
if(*txtpos != ')')
goto expr4_error;
txtpos++;
return a;
}
expr4_error:
expression_error = 1;
return 0;
}
/***************************************************************************/
static short int expr3(void)
{
short int a,b;
a = expr4();
while(1)
{
if(*txtpos == '*')
{
txtpos++;
b = expr4();
a *= b;
}
else if(*txtpos == '/')
{
txtpos++;
b = expr4();
if(b != 0)
a /= b;
else
expression_error = 1;
}
else
return a;
}
}
/***************************************************************************/
static short int expr2(void)
{
short int a,b;
if(*txtpos == '-' || *txtpos == '+')
a = 0;
else
a = expr3();
while(1)
{
if(*txtpos == '-')
{
txtpos++;
b = expr3();
a -= b;
}
else if(*txtpos == '+')
{
txtpos++;
b = expr3();
a += b;
}
else
return a;
}
}
/***************************************************************************/
static short int expression(void)
{
short int a,b;
a = expr2();
// Check if we have an error
if(expression_error) return a;
scantable(relop_tab);
if(table_index == RELOP_UNKNOWN)
return a;
switch(table_index)
{
case RELOP_GE:
b = expr2();
if(a >= b) return 1;
break;
case RELOP_NE:
b = expr2();
if(a != b) return 1;
break;
case RELOP_GT:
b = expr2();
if(a > b) return 1;
break;
case RELOP_EQ:
b = expr2();
if(a == b) return 1;
break;
case RELOP_LE:
b = expr2();
if(a <= b) return 1;
break;
case RELOP_LT:
b = expr2();
if(a < b) return 1;
break;
}
return 0;
}
/***************************************************************************/
void loop()
{
unsigned char *start;
unsigned char *newEnd;
unsigned char linelen;
program_start = program;
program_end = program_start;
sp = program+sizeof(program); // Needed for printnum
stack_limit = program+sizeof(program)-STACK_SIZE;
variables_begin = stack_limit - 27*VAR_SIZE;
printmsg(initmsg);
printnum(variables_begin-program_end);
printmsg(memorymsg);
warmstart:
// this signifies that it is running in 'direct' mode.
current_line = 0;
sp = program+sizeof(program);
printmsg(okmsg);
prompt:
getln('>');
toUppercaseBuffer();
txtpos = program_end+sizeof(unsigned short);
// Find the end of the freshly entered line
while(*txtpos != NL)
txtpos++;
// Move it to the end of program_memory
{
unsigned char *dest;
dest = variables_begin-1;
while(1)
{
*dest = *txtpos;
if(txtpos == program_end+sizeof(unsigned short))
break;
dest--;
txtpos--;
}
txtpos = dest;
}
// Now see if we have a line number
linenum = testnum();
ignore_blanks();
if(linenum == 0)
goto direct;
if(linenum == 0xFFFF)
goto qhow;
// Find the length of what is left, including the (yet-to-be-populated) line header
linelen = 0;
while(txtpos[linelen] != NL)
linelen++;
linelen++; // Include the NL in the line length
linelen += sizeof(unsigned short)+sizeof(char); // Add space for the line number and line length
// Now we have the number, add the line header.
txtpos -= 3;
*((unsigned short *)txtpos) = linenum;
txtpos[sizeof(LINENUM)] = linelen;
// Merge it into the rest of the program
start = findline();
// If a line with that number exists, then remove it
if(start != program_end && *((LINENUM *)start) == linenum)
{
unsigned char *dest, *from;
unsigned tomove;
from = start + start[sizeof(LINENUM)];
dest = start;
tomove = program_end - from;
while( tomove > 0)
{
*dest = *from;
from++;
dest++;
tomove--;
}
program_end = dest;
}
if(txtpos[sizeof(LINENUM)+sizeof(char)] == NL) // If the line has no txt, it was just a delete
goto prompt;
// Make room for the new line, either all in one hit or lots of little shuffles
while(linelen > 0)
{
unsigned int tomove;
unsigned char *from,*dest;
unsigned int space_to_make;
space_to_make = txtpos - program_end;
if(space_to_make > linelen)
space_to_make = linelen;
newEnd = program_end+space_to_make;
tomove = program_end - start;
// Source and destination - as these areas may overlap we need to move bottom up
from = program_end;
dest = newEnd;
while(tomove > 0)
{
from--;
dest--;
*dest = *from;
tomove--;
}
// Copy over the bytes into the new space
for(tomove = 0; tomove < space_to_make; tomove++)
{
*start = *txtpos;
txtpos++;
start++;
linelen--;
}
program_end = newEnd;
}
goto prompt;
unimplemented:
printmsg(unimplimentedmsg);
goto prompt;
qhow:
printmsg(howmsg);
goto prompt;
qwhat:
printmsgNoNL(whatmsg);
if(current_line != NULL)
{
unsigned char tmp = *txtpos;
if(*txtpos != NL)
*txtpos = '^';
list_line = current_line;
printline();
*txtpos = tmp;
}
line_terminator();
goto prompt;
qsorry:
printmsg(sorrymsg);
goto warmstart;
run_next_statement:
while(*txtpos == ':')
txtpos++;
ignore_blanks();
if(*txtpos == NL)
goto execnextline;
goto interperateAtTxtpos;
direct:
txtpos = program_end+sizeof(LINENUM);
if(*txtpos == NL)
goto prompt;
interperateAtTxtpos:
if(breakcheck())
{
printmsg(breakmsg);
goto warmstart;
}
scantable(keywords);
switch(table_index)
{
case KW_LIST:
goto list;
case KW_LOAD:
goto unimplemented; /////////////////
case KW_NEW:
if(txtpos[0] != NL)
goto qwhat;
program_end = program_start;
goto prompt;
case KW_RUN:
current_line = program_start;
goto execline;
case KW_SAVE:
goto unimplemented; //////////////////////
case KW_NEXT:
goto next;
case KW_LET:
goto assignment;
case KW_IF:
short int val;
expression_error = 0;
val = expression();
if(expression_error || *txtpos == NL)
goto qhow;
if(val != 0)
goto interperateAtTxtpos;
goto execnextline;
case KW_GOTO:
expression_error = 0;
linenum = expression();
if(expression_error || *txtpos != NL)
goto qhow;
current_line = findline();
goto execline;
case KW_GOSUB:
goto gosub;
case KW_RETURN:
goto gosub_return;
case KW_REM:
goto execnextline; // Ignore line completely
case KW_FOR:
goto forloop;
case KW_INPUT:
goto input;
case KW_PRINT:
goto print;
case KW_POKE:
goto poke;
case KW_STOP:
// This is the easy way to end - set the current line to the end of program attempt to run it
if(txtpos[0] != NL)
goto qwhat;
current_line = program_end;
goto execline;
case KW_BYE:
// Leave the basic interperater
return;
case KW_DEFAULT:
goto assignment;
default:
break;
}
execnextline:
if(current_line == NULL) // Processing direct commands?
goto prompt;
current_line += current_line[sizeof(LINENUM)];
execline:
if(current_line == program_end) // Out of lines to run
goto warmstart;
txtpos = current_line+sizeof(LINENUM)+sizeof(char);
goto interperateAtTxtpos;
input:
{
unsigned char var;
ignore_blanks();
if(*txtpos < 'A' || *txtpos > 'Z')
goto qwhat;
var = *txtpos;
txtpos++;
ignore_blanks();
if(*txtpos != NL && *txtpos != ':')
goto qwhat;
((short int *)variables_begin)[var-'A'] = 99;
goto run_next_statement;
}
forloop:
{
unsigned char var;
short int initial, step, terminal;
ignore_blanks();
if(*txtpos < 'A' || *txtpos > 'Z')
goto qwhat;
var = *txtpos;
txtpos++;
ignore_blanks();
if(*txtpos != '=')
goto qwhat;
txtpos++;
ignore_blanks();
expression_error = 0;
initial = expression();
if(expression_error)
goto qwhat;
scantable(to_tab);
if(table_index != 0)
goto qwhat;
terminal = expression();
if(expression_error)
goto qwhat;
scantable(step_tab);
if(table_index == 0)
{
step = expression();
if(expression_error)
goto qwhat;
}
else
step = 1;
ignore_blanks();
if(*txtpos != NL && *txtpos != ':')
goto qwhat;
if(!expression_error && *txtpos == NL)
{
struct stack_for_frame *f;
if(sp + sizeof(struct stack_for_frame) < stack_limit)
goto qsorry;
sp -= sizeof(struct stack_for_frame);
f = (struct stack_for_frame *)sp;
((short int *)variables_begin)[var-'A'] = initial;
f->frame_type = STACK_FOR_FLAG;
f->for_var = var;
f->terminal = terminal;
f->step = step;
f->txtpos = txtpos;
f->current_line = current_line;
goto run_next_statement;
}
}
goto qhow;
gosub:
expression_error = 0;
linenum = expression();
if(!expression_error && *txtpos == NL)
{
struct stack_gosub_frame *f;
if(sp + sizeof(struct stack_gosub_frame) < stack_limit)
goto qsorry;
sp -= sizeof(struct stack_gosub_frame);
f = (struct stack_gosub_frame *)sp;
f->frame_type = STACK_GOSUB_FLAG;
f->txtpos = txtpos;
f->current_line = current_line;
current_line = findline();
goto execline;
}
goto qhow;
next:
// Fnd the variable name
ignore_blanks();
if(*txtpos < 'A' || *txtpos > 'Z')
goto qhow;
txtpos++;
ignore_blanks();
if(*txtpos != ':' && *txtpos != NL)
goto qwhat;
gosub_return:
// Now walk up the stack frames and find the frame we want, if present
tempsp = sp;
while(tempsp < program+sizeof(program)-1)
{
switch(tempsp[0])
{
case STACK_GOSUB_FLAG:
if(table_index == KW_RETURN)
{
struct stack_gosub_frame *f = (struct stack_gosub_frame *)tempsp;
current_line = f->current_line;
txtpos = f->txtpos;
sp += sizeof(struct stack_gosub_frame);
goto run_next_statement;
}
// This is not the loop you are looking for... so Walk back up the stack
tempsp += sizeof(struct stack_gosub_frame);
break;
case STACK_FOR_FLAG:
// Flag, Var, Final, Step
if(table_index == KW_NEXT)
{
struct stack_for_frame *f = (struct stack_for_frame *)tempsp;
// Is the the variable we are looking for?
if(txtpos[-1] == f->for_var)
{
short int *varaddr = ((short int *)variables_begin) + txtpos[-1] - 'A';
*varaddr = *varaddr + f->step;
// Use a different test depending on the sign of the step increment
if((f->step > 0 && *varaddr <= f->terminal) || (f->step < 0 && *varaddr >= f->terminal))
{
// We have to loop so don't pop the stack
txtpos = f->txtpos;
current_line = f->current_line;
goto run_next_statement;
}
// We've run to the end of the loop. drop out of the loop, popping the stack
sp = tempsp + sizeof(struct stack_for_frame);
goto run_next_statement;
}
}
// This is not the loop you are looking for... so Walk back up the stack
tempsp += sizeof(struct stack_for_frame);
break;
default:
printf("Stack is stuffed!\n");
goto warmstart;
}
}
// Didn't find the variable we've been looking for
goto qhow;
assignment:
{
short int value;
short int *var;
if(*txtpos < 'A' || *txtpos > 'Z')
goto qhow;
var = (short int *)variables_begin + *txtpos - 'A';
txtpos++;
ignore_blanks();
if (*txtpos != '=')
goto qwhat;
txtpos++;
ignore_blanks();
expression_error = 0;
value = expression();
if(expression_error)
goto qwhat;
// Check that we are at the end of the statement
if(*txtpos != NL && *txtpos != ':')
goto qwhat;
*var = value;
}
goto run_next_statement;
poke:
{
short int value;
unsigned char *address;
// Work out where to put it
expression_error = 0;
value = expression();
if(expression_error)
goto qwhat;
address = (unsigned char *)value;
// check for a comma
ignore_blanks();
if (*txtpos != ',')
goto qwhat;
txtpos++;
ignore_blanks();
// Now get the value to assign
expression_error = 0;
value = expression();
if(expression_error)
goto qwhat;
printf("Poke %p value %i\n",address, (unsigned char)value);
// Check that we are at the end of the statement
if(*txtpos != NL && *txtpos != ':')
goto qwhat;
}
goto run_next_statement;
list:
linenum = testnum(); // Retuns 0 if no line found.
// Should be EOL
if(txtpos[0] != NL)
goto qwhat;
// Find the line
list_line = findline();
while(list_line != program_end)
printline();
goto warmstart;
print:
// If we have an empty list then just put out a NL
if(*txtpos == ':' )
{
line_terminator();
txtpos++;
goto run_next_statement;
}
if(*txtpos == NL)
{
goto execnextline;
}
while(1)
{
ignore_blanks();
if(print_quoted_string())
{
;
}
else if(*txtpos == '"' || *txtpos == '\'')
goto qwhat;
else
{
short int e;
expression_error = 0;
e = expression();
if(expression_error)
goto qwhat;
printnum(e);
}
// At this point we have three options, a comma or a new line
if(*txtpos == ',')
txtpos++; // Skip the comma and move onto the next
else if(txtpos[0] == ';' && (txtpos[1] == NL || txtpos[1] == ':'))
{
txtpos++; // This has to be the end of the print - no newline
break;
}
else if(*txtpos == NL || *txtpos == ':')
{
line_terminator(); // The end of the print statement
break;
}
else
goto qwhat;
}
goto run_next_statement;
}
/***************************************************************************/
static void line_terminator(void)
{
outchar(NL);
outchar(CR);
}
/***********************************************************/
void setup()
{
#if ARDUINO
Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
#endif
}
/***********************************************************/
static unsigned char breakcheck(void)
{
#if ARDUINO
if(Serial.available())
return Serial.read() == CTRLC;
return 0;
#else
if(kbhit())
return getch() == CTRLC;
else
return 0;
#endif
}
/***********************************************************/
static int inchar()
{
#if ARDUINO
while(1)
{
if(Serial.available())
return Serial.read();
}
#else
return getchar();
#endif
}
/***********************************************************/
static void outchar(unsigned char c)
{
#if ARDUINO
Serial.write(c);
#else
putchar(c);
#endif
}
) Megint hibaüzenet,egyet elhárítok ,jön a következő. Nekem az alap TinyBasic sem fut le a megán valamiért,ott állandóan az eeprom-ra hivatkozik. (most a TVout shield-et próbálom hogy hátha ezen jönne kép,de le se fut a program)
(Klón mega 2560-at használok,viszont drivere fentvan,használtam már ezt a programozót internet shield-hez. 
