Diff: ttbasic.cpp

Revision:

0:f7402df15e75

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttbasic.cpp	Fri May 08 06:16:48 2015 +0000
@@ -0,0 +1,1243 @@
+/*
+    TOYOSHIKI TinyBASIC V1.0
+    Reference source
+    (C)2012 Tetsuya Suzuki, All rights reserved.
+*/
+
+// Compiler requires description
+//#include <stdlib.h>
+//#include "sci.h"
+#include "mbed.h"
+
+#if defined(TARGET_LPC1114)
+Serial pc(dp16, dp15);
+#else
+Serial pc(USBTX, USBRX);
+#endif
+
+// Depending on device functions
+// TO-DO Rewrite these functions to fit your machine
+// And see 'getrnd()'
+//void c_putch(char c){putch2(c);}
+//char c_getch(){return getch2();}
+//char c_kbhit(){return(kbhit2());}
+void c_putch(char c){pc.putc(c);}
+char c_getch(){return pc.getc();}
+char c_kbhit(){return(pc.readable());}
+void newline(void){
+    c_putch(13); //CR
+    c_putch(10); //LF
+}
+
+// TOYOSHIKI TinyBASIC symbols
+// TO-DO Rewrite defined values to fit your machine as needed
+#define SIZE_LINE 64 //Command line buffer length + NULL
+#define SIZE_IBUF 64 //i-code conversion buffer size
+#define SIZE_LIST 1024 //List buffer size
+#define SIZE_ARRY 32 //Array area size
+#define SIZE_GSTK 6 //GOSUB stack size(2/nest)
+#define SIZE_LSTK 15 //FOR stack size(5/nest)
+
+// RAM mapping
+char lbuf[SIZE_LINE]; //Command line buffer
+unsigned char ibuf[SIZE_IBUF]; //i-code conversion buffer
+short var[26]; //Variable area
+short arr[SIZE_ARRY]; //Array area
+unsigned char listbuf[SIZE_LIST]; //List area
+unsigned char* clp; //Pointer current line
+unsigned char* cip; //Pointer current Intermediate code
+unsigned char* gstk[SIZE_GSTK]; //GOSUB stack
+unsigned char gstki; //GOSUB stack index
+unsigned char* lstk[SIZE_LSTK]; //FOR stack
+unsigned char lstki; //FOR stack index
+
+// Prototypes (necessity minimum)
+short iexp(void);
+
+// Keyword table
+const char* kwtbl[] = {
+    "GOTO", "GOSUB", "RETURN",
+    "FOR", "TO", "STEP", "NEXT",
+    "IF", "REM", "STOP",
+    "INPUT", "PRINT", "LET",
+    ",", ";",
+    "-", "+", "*", "/", "(", ")",
+    ">=", "#", ">", "=", "<=", "<",
+     "@", "RND", "ABS", "SIZE",
+    "LIST", "RUN", "NEW"
+};
+
+// Keyword count
+#define SIZE_KWTBL (sizeof(kwtbl) / sizeof(const char*))
+
+// i-code(Intermediate code) assignment
+enum{
+    I_GOTO, I_GOSUB, I_RETURN,
+    I_FOR, I_TO, I_STEP, I_NEXT,
+    I_IF, I_REM, I_STOP,
+    I_INPUT, I_PRINT, I_LET,
+    I_COMMA, I_SEMI,
+    I_MINUS, I_PLUS, I_MUL, I_DIV, I_OPEN, I_CLOSE,
+    I_GTE, I_SHARP, I_GT, I_EQ, I_LTE, I_LT,
+    I_ARRAY, I_RND, I_ABS, I_SIZE,
+    I_LIST, I_RUN, I_NEW,
+    I_NUM, I_VAR, I_STR,
+    I_EOL
+};
+
+// List formatting condition
+#define IS_OP(p) (p >= I_MINUS && p <= I_LT) // Operator style
+#define IS_SEP(p) (p == I_COMMA || p == I_SEMI) // Separator style
+#define IS_TOKSP(p) (/*p >= I_GOTO && */p <= I_LET && p != I_RETURN) // Token style
+
+// Error messages
+unsigned char err;// Error message index
+const char* errmsg[] ={
+    "OK",
+    "Devision by zero",
+    "Overflow",
+    "Subscript out of range",
+    "Icode buffer full",
+    "List full",
+    "GOSUB too many nested",
+    "RETURN stack underflow",
+    "FOR too many nested",
+    "NEXT without FOR",
+    "NEXT without counter",
+    "NEXT mismatch FOR",
+    "FOR without variable",
+    "FOR without TO",
+    "LET without variable",
+    "IF without condition",
+    "Undefined line number",
+    "\'(\' or \')\' expected",
+    "\'=\' expected",
+    "Illegal command",
+    "Syntax error",
+    "Internal error",
+    "Abort by [ESC]"
+};
+
+// Error code assignment
+enum{
+    ERR_OK,
+    ERR_DIVBY0,
+    ERR_VOF,
+    ERR_SOL,
+    ERR_IBUFOF,
+    ERR_LBUFOF,
+    ERR_GSTKOF,
+    ERR_GSTKUF,
+    ERR_LSTKOF,
+    ERR_LSTKUF,
+    ERR_NEXTWOV,
+    ERR_NEXTUM,
+    ERR_FORWOV,
+    ERR_FORWOTO,
+    ERR_LETWOV,
+    ERR_IFWOC,
+    ERR_ULN,
+    ERR_PAREN,
+    ERR_VWOEQ,
+    ERR_COM,
+    ERR_SYNTAX,
+    ERR_SYS,
+    ERR_ESC
+};
+
+// Standard C libraly (about same) functions
+char c_toupper(char c) {return(c <= 'z' && c >= 'a' ? c - 32 : c);}
+char c_isprint(char c) {return(c >= 32  && c <= 126);}
+char c_isspace(char c) {return(c <= ' ' &&(c == ' ' || (c <= 13 && c >= 9)));}
+char c_isdigit(char c) {return(c <= '9' && c >= '0');}
+char c_isalpha(char c) {return ((c <= 'z' && c >= 'a') || (c <= 'Z' && c >= 'A'));}
+char* c_strchr(char *s, char c){
+    while(*s) {
+        if(*s == c) return (s);
+    ++s;
+    }
+    return NULL;
+}
+void c_puts(const char *s) {while(*s) c_putch(*s++);}
+void c_gets(){
+    char c;
+    unsigned char len;
+
+    len = 0;
+    while((c = c_getch()) != 13){
+        if( c == 9) c = ' '; // TAB exchange Space
+        if((c == 8) && (len > 0)){ // Backspace manipulation
+            len--;
+            c_putch(8); c_putch(' '); c_putch(8);
+        } else
+        if(c_isprint(c) && (len < (SIZE_LINE - 1))){
+            lbuf[len++] = c;
+            c_putch(c);
+        }
+    }
+    newline();
+    lbuf[len] = 0; // Put NULL
+
+    if(len > 0){
+        while(c_isspace(lbuf[--len])); // Skip space
+        lbuf[++len] = 0; // Put NULL
+    }
+}
+
+// GOSUB-RETURN stack
+void gpush(unsigned char* pd){
+    if(gstki < SIZE_GSTK){
+        gstk[gstki++] = pd;
+        return;
+    }
+    err = ERR_GSTKOF;
+}
+
+unsigned char* gpop(){
+    if(gstki > 0){
+        return gstk[--gstki];
+    }
+    err = ERR_GSTKUF;
+    return NULL;
+}
+
+// FOR-NEXT stack
+void lpush(unsigned char* pd){
+    if(lstki < SIZE_LSTK){
+        lstk[lstki++] = pd;
+        return;
+    }
+    err = ERR_LSTKOF;
+}
+
+unsigned char* lpop(){
+    if(lstki > 0){
+        return lstk[--lstki];
+    }
+    err = ERR_LSTKUF;
+    return NULL;
+}
+
+// Print OK or error message
+void error()
+{
+    newline();
+    c_puts(errmsg[err]);
+    newline();
+    err = 0;
+}
+
+// Print numeric specified columns
+void putnum(short value, short d){
+    unsigned char i;
+    unsigned char sign;
+
+    if(value < 0){
+        sign = 1;
+        value = -value;
+    } else {
+        sign = 0;
+    }
+
+    lbuf[6] = 0;
+    i = 6;
+    do {
+        lbuf[--i] = (value % 10) + '0';
+        value /= 10;
+    } while(value > 0);
+
+    if(sign)
+        lbuf[--i] = '-';
+
+    //String length = 6 - i
+    while(6 - i < d){ // If short
+        c_putch(' '); // Fill space
+        d--;
+    }
+    c_puts(&lbuf[i]);
+}
+
+// Input numeric and return value
+// Called by only INPUT statement
+short getnum(){
+    short value, tmp;
+    char c;
+    unsigned char len;
+    unsigned char sign;
+
+    len = 0;
+    while((c = c_getch()) != 13){
+        if((c == 8) && (len > 0)){ // Backspace manipulation
+            len--;
+            c_putch(8); c_putch(' '); c_putch(8);
+        } else
+        if( (len == 0 && (c == '+' || c == '-')) ||
+            (len < 6 && c_isdigit(c))){ // Numeric or sign only
+            lbuf[len++] = c;
+            c_putch(c);
+        }
+    }
+    newline();
+    lbuf[len] = 0;
+
+    switch(lbuf[0]){
+    case '-':
+        sign = 1;
+        len = 1;
+        break;
+    case '+':
+        sign = 0;
+        len = 1;
+        break;
+    default:
+        sign = 0;
+        len = 0;
+        break;
+    }
+
+    value = 0; // Initialize value
+    tmp = 0; // Temp value
+    while(lbuf[len]){
+        tmp = 10 * value + lbuf[len++] - '0';
+        if(value > tmp){ // It means overflow
+            err = ERR_VOF;
+        }
+        value = tmp;
+    }
+    if(sign)
+        return -value;
+    return value;
+}
+
+// Byte X,L,H -> Short HL
+// Used to get line number or I_NUM value
+short getvalue(unsigned char* ip){
+    if(*ip == 0)
+        return 32767; // Case X = 0
+    return((short)*(ip + 1) + ((short)*(ip + 2) << 8));
+}
+
+// Get argument in parenthesis
+short getparam(){
+    short value;
+
+    if(*cip != I_OPEN){
+        err = ERR_PAREN;
+        return 0;
+    }
+    cip++;
+    value = iexp();
+    if(err) return 0;
+
+    if(*cip != I_CLOSE){
+        err = ERR_PAREN;
+        return 0;
+    }
+    cip++;
+
+    return value;
+}
+
+// Search line by line number
+unsigned char* getlp(short lineno){
+    unsigned char *lp;
+
+    lp = listbuf;
+    while(*lp){
+        if(getvalue(lp) >= lineno)
+            break;
+        lp += *lp;
+    }
+    return lp;
+}
+
+// Convert token to i-code
+// Return byte length or 0
+unsigned char toktoi(){
+    unsigned char i; // Loop counter(i-code sometime)
+    unsigned char len; //byte counter
+    short value;
+    short tmp;
+    char* pkw; // Temporary keyword pointer
+    char* ptok; // Temporary token pointer
+    char c; // Surround the string character, " or '
+    char* s; // Pointer to charactor at line buffer
+
+    s = lbuf;
+    len = 0; // Clear byte length
+    while(*s){
+        while(c_isspace(*s)) s++; // Skip space
+
+        //Try keyword conversion
+        for(i = 0; i < SIZE_KWTBL; i++){
+            pkw = (char *)kwtbl[i]; // Point keyword
+            ptok = s; // Point top of command line
+            // Compare
+            while((*pkw != 0) && (*pkw == c_toupper(*ptok))){
+                pkw++;
+                ptok++;
+            }
+            if(*pkw == 0){// Case success
+                // i have i-code
+                if(len >= SIZE_IBUF - 1){// List area full
+                    err = ERR_IBUFOF;
+                    return 0;
+                }
+                ibuf[len++] = i;
+                s = ptok;
+                break;
+            }
+        }
+
+        // Case statement needs an argument except numeric, valiable, or strings
+        switch(i){
+        case I_REM:
+            while(c_isspace(*s)) s++; // Skip space
+            ptok = s;
+            for(i = 0; *ptok++; i++); // Get length
+            if(len >= SIZE_IBUF - 2 - i){
+                err = ERR_IBUFOF;
+                return 0;
+            }
+            ibuf[len++] = i; // Put length
+            while(i--){ // Copy strings
+                ibuf[len++] = *s++;
+            }
+            return len;
+        default:
+            break;
+        }
+
+        if(*pkw != 0){ // Case not keyword
+            ptok = s; // Point top of command line
+
+            // Try numeric conversion
+            if(c_isdigit(*ptok)){
+                value = 0;
+                tmp = 0;
+                do{
+                    tmp = 10 * value + *ptok++ - '0';
+                    if(value > tmp){
+                        err = ERR_VOF;
+                        return 0;
+                    }
+                    value = tmp;
+                } while(c_isdigit(*ptok));
+
+                if(len >= SIZE_IBUF - 3){
+                    err = ERR_IBUFOF;
+                    return 0;
+                }
+                s = ptok;
+                ibuf[len++] = I_NUM;
+                ibuf[len++] = value & 255;
+                ibuf[len++] = value >> 8;
+            } else
+
+            // Try valiable conversion
+            if(c_isalpha(*ptok)){
+                if(len >= SIZE_IBUF - 2){
+                    err = ERR_IBUFOF;
+                    return 0;
+                }
+                if(len >= 2 && ibuf[len -2] == I_VAR){ // Case series of variables
+                     err = ERR_SYNTAX; // Syntax error
+                     return 0;
+                }
+                ibuf[len++] = I_VAR; // Put i-code
+                ibuf[len++] = c_toupper(*ptok) - 'A'; // Put index of valiable area
+                s++;
+            } else
+
+            // Try string conversion
+            if(*s == '\"' || *s == '\''){// If start of string
+                c = *s;
+                s++; // Skip " or '
+                ptok = s;
+                for(i = 0; (*ptok != c) && c_isprint(*ptok); i++) // Get length
+                    ptok++;
+                if(len >= SIZE_IBUF - 1 - i){ // List area full
+                    err = ERR_IBUFOF;
+                    return 0;
+                }
+                ibuf[len++] = I_STR; // Put i-code
+                ibuf[len++] = i; // Put length
+                while(i--){ // Put string
+                    ibuf[len++] = *s++;
+                }
+                if(*s == c) s++; // Skip " or '
+
+            // Nothing mutch
+            } else {
+                err = ERR_SYNTAX;
+                return 0;
+            }
+        }
+    }
+    ibuf[len++] = I_EOL; // Put end of line
+    return len; // Return byte length
+}
+
+//Listing 1 line of i-code
+void putlist(unsigned char* ip){
+    unsigned char i;
+    short value;
+
+    while(*ip != I_EOL){
+        // Case keyword
+        if(*ip < SIZE_KWTBL){
+            c_puts(kwtbl[*ip]);
+            if(IS_TOKSP(*ip) || *ip == I_SEMI)c_putch(' ');
+            if(*ip == I_REM){
+                ip++;
+                i = *ip++;
+                while(i--){
+                    c_putch(*ip++);
+                }
+                return;
+            }
+            ip++;
+        } else
+
+        // Case numeric
+        if(*ip == I_NUM){
+            putnum(getvalue(ip), 0);
+            ip += 3;
+            if(!IS_OP(*ip) && !IS_SEP(*ip)) c_putch(' ');
+        } else
+
+        // Case valiable
+        if(*ip == I_VAR){
+            ip++;
+            c_putch(*ip++ + 'A');
+            if(!IS_OP(*ip) && !IS_SEP(*ip)) c_putch(' ');
+        } else
+
+        // Case string
+        if(*ip == I_STR){
+            ip++;
+            value = 0;
+            i = *ip;
+            while(i--){
+                if(*(ip + i + 1) == '\"')
+                    value = 1;
+            }
+            if(value) c_putch('\''); else c_putch('\"');
+            i = *ip++;
+            while(i--){
+                c_putch(*ip++);
+            }
+            if(value) c_putch('\''); else c_putch('\"');
+
+        // Nothing match, I think, such case is impossible
+        } else {
+            err = ERR_SYS;
+            return;
+        }
+    }
+}
+
+// Insert i-code to the list
+void inslist(){
+    unsigned char len;
+    unsigned char *lp1, *lp2;
+
+    cip = ibuf;
+    clp = getlp(getvalue(cip));
+
+    lp1 = clp;
+    if(getvalue(lp1) == getvalue(cip)){
+        // Temporary measures of the case that
+        // same line numbere exists and list area full,
+        // existing line is deleted and new line is not inserted in.
+
+        // if((getsize() - *lp1) < *cip){
+        //  err = ERR_LBUFOF;
+        //  return;
+        // }
+
+        lp2 = lp1 + *lp1;
+        while((len = *lp2) != 0){
+            while(len--){
+                *lp1++ = *lp2++;
+            }
+        }
+        *lp1 = 0;
+    }
+
+    // Case line number only
+    if(*cip == 4)
+            return;
+
+    // Check insertable
+    while(*lp1){
+        lp1 += *lp1;
+    }
+    if(*cip > (listbuf + SIZE_LIST - lp1 - 1)){
+        err = ERR_LBUFOF;
+        return;
+    }
+
+    // Make space
+    len = lp1 - clp + 1;
+    lp2 = lp1 + *cip;
+    while(len--){
+        *lp2-- = *lp1--;
+    }
+
+    // Insert
+    len = *cip;
+    while(len--){
+        *clp++ = *cip++;
+    }
+}
+
+// Return free memory
+short getsize(){
+    short value;
+    unsigned char* lp;
+
+    lp = listbuf;
+    while(*lp){
+        lp += *lp;
+    }
+
+    value = listbuf + SIZE_LIST - lp - 1;
+    return value;
+}
+
+// Return Absolute value
+short getabs(){
+    short value;
+
+    value = getparam();
+    if(err) return 0;
+
+    if(value < 0) value *= -1;
+    return value;
+}
+
+// Return random number
+// TO-DO Rewrite this function to fit your machine
+short getrnd(void){
+    short value;
+
+    value = getparam();
+    if(err) return 0;
+
+    return(rand() % value);
+}
+
+short getarray()
+{
+    short index;
+
+    index = getparam();
+    if(err) return 0;
+
+    if(index < SIZE_ARRY){
+        return arr[index];
+    } else {
+        err = ERR_SOL;
+        return 0;
+    }
+}
+
+short ivalue(){
+    short value;
+
+    switch(*cip){
+     case I_PLUS:
+         cip++;
+         value = ivalue();
+         break;
+     case I_MINUS:
+         cip++;
+         value = 0 - ivalue();
+         break;
+     case I_VAR:
+         cip++;
+         value = var[*cip++];
+         break;
+     case I_NUM:
+         value = getvalue(cip);
+         cip += 3;
+         break;
+     case I_ARRAY:
+         cip++;
+        value = getarray();
+        break;
+     case I_OPEN:
+         value = getparam();
+        break;
+     case I_RND:
+        cip++;
+        value = getrnd();
+        break;
+     case I_ABS:
+        cip++;
+        value = getabs();
+        break;
+     case I_SIZE:
+        cip++;
+        if(*cip == I_OPEN){
+            cip++;
+            if(*cip == I_CLOSE)
+                cip++;
+            else{
+                err = ERR_PAREN;
+            }
+        }
+        value = getsize();
+        break;
+
+     default:
+        value = 0;
+        err = ERR_SYNTAX;
+        break;
+    }
+    return value;
+}
+
+short icalc()
+{
+    short value1, value2;
+
+    value1 = ivalue();
+
+    while(1){
+        if(*cip == I_DIV){
+            cip++;
+            value2 = ivalue();
+            if(value2 == 0){
+                err = ERR_DIVBY0;
+                break;
+            }
+            value1 /= value2;
+        } else
+        if(*cip == I_MUL){
+            cip++;
+            value2 = ivalue();
+            value1 *= value2;
+        } else {
+            break;
+        }
+    }
+    return value1;
+}
+
+short iexp()
+{
+    short value1, value2;
+
+    value1 = icalc();
+
+    while(*cip == I_PLUS || *cip == I_MINUS){
+        value2 = icalc();
+        value1 += value2;
+    }
+    return value1;
+}
+
+void iprint(){
+    short value;
+    short len;
+    unsigned char i;
+
+    len = 0;
+    while(1){
+        switch(*cip){
+        case I_SEMI:
+        case I_EOL:
+            break;
+        case I_STR:
+            cip++;
+            i = *cip++;
+            while(i--){
+                c_putch(*cip++);
+            }
+            break;
+        case I_SHARP:
+            cip++;
+            len = iexp();
+            if(err) return;
+            break;
+        default:
+            value = iexp();
+            if(err) return;
+            putnum(value, len);
+            break;
+        }
+
+        if(*cip == I_COMMA){
+            cip++;
+        }else{
+            break;
+        }
+    };
+    newline();
+}
+
+void iinput(){
+    unsigned char i;
+    short value;
+    short index;
+
+    while(1){
+        switch(*cip){
+        case I_STR:
+            cip++;
+            i = *cip++;
+            while(i--){
+                c_putch(*cip++);
+            }
+            if(*cip == I_VAR){
+                cip++;
+                value = getnum();
+                var[*cip++] = value;
+            } else
+            if(*cip == I_ARRAY){
+                cip++;
+                index = getparam();
+                if(err) return;
+                if(index >= SIZE_ARRY){
+                    err = ERR_SOL;
+                    return;
+                }
+                value = getnum();
+                arr[index] = value;
+            }
+            break;
+        case I_VAR:
+            cip++;
+            c_putch(*cip + 'A');
+            c_putch(':');
+            value = getnum();
+            var[*cip++] = value;
+            break;
+        case I_ARRAY:
+            cip++;
+            index = getparam();
+            if(err)
+                return;
+            if(index >= SIZE_ARRY){
+                err = ERR_SOL;
+                return;
+            }
+            c_putch('@');c_putch('(');
+            putnum(index,0);
+            c_putch(')');c_putch(':');
+            value = getnum();
+            arr[index] = value;
+            break;
+        }
+
+        switch(*cip){
+        case I_COMMA:
+            cip++;
+            break;
+        case I_SEMI:
+        case I_EOL:
+            return;
+        default:
+            err = ERR_SYNTAX;
+            return;
+        }
+    }
+}
+
+//char iif(){
+signed char iif(){
+    short value1, value2;
+    unsigned char i;
+    
+    value1 = iexp();
+    if(err) return -1;
+
+    i = *cip++;
+
+    value2 = iexp();
+    if(err) return -1;
+
+    switch(i){
+    case I_EQ:
+        return value1 == value2;
+    case I_SHARP:
+        return value1 != value2;
+    case I_LT:
+        return value1 <  value2;
+    case I_LTE:
+        return value1 <= value2;
+    case I_GT:
+        return value1 >  value2;
+    case I_GTE:
+        return value1 >= value2;
+    default:
+         err = ERR_IFWOC;
+         return -1;
+    }
+}
+
+void ivar(){
+    short value;
+    short index;
+
+    index = *cip++;
+    if(*cip == I_EQ){
+        cip++;
+        value = iexp();
+        if(err) return;
+    } else {
+        err = ERR_VWOEQ;
+        return;
+    }
+
+    if(index < 26){
+        var[index] = value;
+    } else {
+        err = ERR_SOL;
+    }
+}
+
+void iarray(){
+    short value;
+    short index;
+
+    index = getparam();
+    if(err) return;
+    if(*cip == I_EQ){
+        cip++;
+        value = iexp();
+        if(err) return;
+    } else {
+        err = ERR_VWOEQ;
+        return;
+    }
+
+    if(index < SIZE_ARRY){
+        arr[index] = value;
+    } else {
+        err = ERR_SOL;
+    }
+}
+
+void ilet(){
+    switch(*cip){
+     case I_VAR:
+        cip++;
+        ivar();
+        break;
+    case I_ARRAY:
+        cip++;
+        iarray();
+        break;
+     default:
+        err = ERR_LETWOV;
+        break;
+    }
+}
+
+void ilist(){
+    short lineno;
+
+    if(*cip == I_NUM){
+        lineno = getvalue(cip);
+        cip += 3;
+    } else {
+        lineno = 0;
+    }
+
+    for(    clp = listbuf;
+            *clp && (getvalue(clp) < lineno);
+            clp += *clp);
+
+    while(*clp){
+        putnum(getvalue(clp), 0);
+        c_putch(' ');
+        putlist(clp + 3);
+        if(err){
+            break;
+        }
+        newline();
+        clp += *clp;
+    }
+}
+
+void inew(void){
+    unsigned char i;
+
+    for(i = 0; i < 26; i++)
+        var[i] = 0;
+    gstki = 0;
+    lstki = 0;
+    *listbuf = 0;
+    clp = listbuf;
+}
+
+unsigned char* iexe(){
+    short lineno;
+    unsigned char cd;
+    unsigned char* lp;
+    short vto, vstep;
+    short index;
+
+    while(1){
+        if(c_kbhit()){
+            if(c_getch() == 27){
+                while(*clp){
+                    clp += *clp;
+                }
+                err = ERR_ESC;
+                return clp;
+            }
+        }
+
+        switch(*cip){
+        case I_GOTO:
+            cip++;
+            lineno = iexp();
+            clp = getlp(lineno);
+            if(lineno != getvalue(clp)){
+                err = ERR_ULN;
+                return NULL;
+            }
+            cip = clp + 3;
+            continue;
+        case I_GOSUB:
+            cip++;
+            lineno = iexp();
+            if(err) return NULL;
+            lp = getlp(lineno);
+            if(lineno != getvalue(lp)){
+                err = ERR_ULN;
+                return NULL;
+            }
+            gpush(clp);
+            gpush(cip);
+            if(err) return NULL;
+            clp = lp;
+            cip = clp + 3;
+            continue;
+        case I_RETURN:
+            cip = gpop();
+            lp = gpop();
+            if(err) return NULL;
+            clp = lp;
+            break;
+        case I_FOR:
+            cip++;
+            if(*cip++ != I_VAR){
+                err = ERR_FORWOV;
+                return NULL;
+            }
+            index = *cip;
+            ivar();
+            if(err) return NULL;
+
+            if(*cip == I_TO){
+                cip++;
+                vto = iexp();
+            } else {
+                err = ERR_FORWOTO;
+                return NULL;
+            }
+            if(*cip == I_STEP){
+                cip++;
+                vstep = iexp();
+            } else {
+                vstep = 1;
+            }
+
+            lpush(clp);
+            lpush(cip);
+            lpush((unsigned char*)vto);
+            lpush((unsigned char*)vstep);
+            lpush((unsigned char*)index);
+            if(err) return NULL;
+            break;
+        case I_NEXT:
+            cip++;
+            if(*cip++ !=I_VAR){
+                err = ERR_NEXTWOV;
+                return NULL;
+            }
+
+            if(lstki < 5){
+                err = ERR_LSTKUF;
+                return NULL;
+            }
+            index = (short)lstk[lstki - 1];
+            if(index != *cip){
+                err = ERR_NEXTUM;
+                return NULL;
+            }
+            cip++;
+            vstep = (short)lstk[lstki - 2];
+            var[index] += vstep;
+
+            vto = (short)lstk[lstki - 3];
+            if( ((vstep < 0) && (var[index] < vto)) ||
+                ((vstep > 0) && (var[index] > vto))){
+                lstki -= 5;
+                break;
+            }
+            cip = lstk[lstki - 4];
+            clp = lstk[lstki - 5];
+            continue;
+
+        case I_IF:
+            cip++;
+            cd = iif();
+            if(err){
+                err = ERR_IFWOC;
+                return NULL;
+            }
+            if(cd)
+                continue;
+            // If false, same as REM
+        case I_REM:
+            // Seek pointer to I_EOL
+            // No problem even if it points not realy end of line
+            while(*cip != I_EOL) cip++;
+            break;
+        case I_STOP:
+            while(*clp){
+                clp += *clp;
+            }
+            return clp;
+        case I_INPUT:
+            cip++;
+            iinput();
+            break;
+        case I_PRINT:
+            cip++;
+            iprint();
+            break;
+        case I_LET:
+            cip++;
+            ilet();
+            break;
+        case I_VAR:
+            cip++;
+            ivar();
+            break;
+        case I_ARRAY:
+            cip++;
+            iarray();
+            break;
+        case I_LIST:
+        case I_NEW:
+        case I_RUN:
+            err = ERR_COM;
+            return NULL;
+        }
+
+        switch(*cip){
+        case I_SEMI:
+            cip++;
+            break;
+        case I_EOL:
+            return clp + *clp;
+        default:
+            err = ERR_SYNTAX;
+            return NULL;
+        }
+    }
+}
+
+void irun(){
+    unsigned char* lp;
+
+    gstki = 0;
+    lstki = 0;
+    clp = listbuf;
+    
+    while(*clp){
+        cip = clp + 3;
+        lp = iexe();
+        if(err)
+            return;
+        clp = lp;
+    }
+}
+
+void icom(){
+    cip = ibuf;
+    switch(*cip){
+    case I_LIST:
+        cip++;
+        if(*cip == I_EOL || *(cip + 3) == I_EOL)
+            ilist();
+        else
+            err = ERR_SYNTAX;
+        break;
+    case I_NEW:
+        cip++;
+        if(*cip == I_EOL)
+            inew();
+        else
+            err = ERR_SYNTAX;
+        break;
+    case I_RUN:
+        cip++;
+        irun();
+        break;
+    default:
+        iexe();
+        break;
+    }
+
+    if(err && err != ERR_ESC){
+        if(cip >= listbuf && cip < listbuf + SIZE_LIST && *clp)
+        {
+            newline(); c_puts("ERR LINE:");
+            putnum(getvalue(clp), 0);
+            c_putch(' ');
+            putlist(clp + 3);
+        }
+        else
+        {
+            newline(); c_puts("YOU TYPE: ");
+            putlist(ibuf);
+        }
+    }
+    
+}
+
+void basic(){
+    unsigned char len;
+
+//  sci2_init();
+    pc.baud(9600);
+    inew();
+    c_puts("TOYOSHIKI TINY BASIC"); newline();
+//    c_puts("PIC24F EDITION"); newline();
+    c_puts("mbed EDITION"); newline();
+    error(); // Print OK, and Clear error flag
+
+    // Input 1 line and execute
+    while(1){
+        c_putch('>');// Prompt
+        c_gets(); // Input 1 line
+        len = toktoi(); // Convert token to i-code
+        if(err){ // Error
+            newline(); c_puts("YOU TYPE:");
+            c_puts(lbuf);
+            error();
+            continue; // Do nothing
+        }
+
+        if(*ibuf == I_NUM){ // Case the top includes line number
+            *ibuf = len; // Change I_NUM to byte length
+            inslist(); // Insert list
+            if(err){
+                error(); // List buffer overflow
+            }
+        } else {
+            icom(); // Execute direct
+            error(); // Print OK, and Clear error flag
+        }
+    }
+}
+
+