All FWIK is deleted. YOSH is now pure C. Not-working KBASIC included.

1 files changed, 511 insertions, 0 deletions

diff --git a/src/user/app/kbasic/control.c b/src/user/app/kbasic/control.c
new file mode 100644
index 0000000..1ab22ff
--- /dev/null
+++ b/src/user/app/kbasic/control.c
@@ -0,0 +1,511 @@
+#include <stdio.h>
+#include <string.h>
+// #include <sys/wait.h>
+// #include <unistd.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <setjmp.h>
+
+#include "basic.h"
+
+struct label {
+	char name[LAB_LEN];
+	char *p;  /* points to place to go in source file*/
+};
+struct for_stack {
+	int *var; /* counter variable */
+	int target;  /* target value */
+	char *loc;
+};
+
+struct label label_table[NUM_LAB];
+
+char *gstack[SUB_NEST];	/* stack for gosub */
+struct for_stack fstack[FOR_NEST];	/* stack for FOR/NEXT loop */
+
+int ftos;  /* index to top of FOR stack */
+int gtos;  /* index to top of GOSUB stack */
+
+char *program, *prog_ip;  /* holds expression to be analyzed */
+
+char *interp_name;
+
+jmp_buf e_buf; /* hold environment for longjmp() */
+
+char *find_label();
+void scan_labels();
+struct for_stack fpop();
+char *gpop();
+int get_next_label(char *);
+void fpush(struct for_stack); 
+void gosub(), greturn(), gpush(char*), label_init();
+void exec_if(), exec_for(), next(), exec_goto();
+void exec_exec(), exec_load();
+void exec_list();
+
+/* initialize variables */
+void init() {
+	program = NULL;
+	prog_ip = NULL;
+	label_init();
+}
+
+/* Load program and scans labels */
+void load_program (char *p_buf) {
+	if (program != NULL) {
+		free(program);
+	}
+
+	program = p_buf;
+	scan_labels(); /* find the labels in the program */
+}
+
+/* Insert line at the right place of program */
+void insert_line(char *l, int n) {
+	char *a, *b, *p;
+	int i_n, t, k;
+
+
+	if (program == NULL) {
+		load_program(strdup(l));
+	} else {
+		int prog_l = strlen(program);
+
+		// lookup insert position
+		// find smallest label above line number
+		a = (n == 0 ? program : program + prog_l);
+		i_n = -1; b = program + prog_l;
+
+		for (t = 0; t < NUM_LAB; t++) {
+			if (label_table[t].name[0]) {
+				k = atoi(label_table[t].name);
+				if (k == n) {
+					a = label_table[t].p;
+					while (*a != '\n' && a > program) a--;	// back to beginning of line
+					if (*a == '\n') a++;
+				}
+				if (k > n && (k < i_n || i_n == -1)) {
+					i_n = k;
+					b = label_table[t].p;
+					while (*b != '\n' && b > program) b--;	// back to beginning of line
+					if (*b == '\n') b++;
+					if (b < a) a = b;
+				}
+			}
+		}
+
+		p = malloc(prog_l + strlen(l) + 3);
+
+		strncpy(p, program, (a - program));		// copy [0, a[
+		p[a - program] = 0;
+		// if l is an empty line, do not copy.
+		for (i_n = 0; l[i_n]; i_n++) {
+			if (!isdigit(l[i_n]) && l[i_n] != '\n' && l[i_n] != '\r') {
+				strcpy(p + (a - program), l);	// copy l
+				break;
+			}
+		}
+		strcat(p + (a - program), b);			// copy [b, end[
+
+		load_program(p);	// reparse labels
+	}
+}
+
+/* start program execution at given entry point (not necessarily in loaded program)
+	return values :
+	- 0 : return on end of input
+	- 1 : return on error
+	- 2 : return on "END" statement
+	- 3 : return on "LOAD" statement
+*/
+int start(char *entry) {
+	ftos = 0; /* initialize the FOR stack index */
+	gtos = 0; /* initialize the GOSUB stack index */
+
+	prog_ip = entry;
+	if(setjmp(e_buf)) return 1; /* initialize the long jump buffer */
+
+	do {
+		token_type = get_token();
+		/* check for assignment statement */
+		if(token_type==VARIABLE) {
+			putback(); /* return the var to the input stream */
+			assignment(); /* must be assignment statement */
+		}
+		else /* is command */
+			switch(tok) {
+				case LIST:
+					exec_list();
+					break;
+				case PRINT:
+					exec_print();
+					break;
+				case GOTO:
+					exec_goto();
+					break;
+				case IF:
+					exec_if();
+					break;
+				case FOR:
+					exec_for();
+					break;
+				case NEXT:
+					next();
+					break;
+				case INPUT:
+					input();
+					break;
+				case GOSUB:
+					gosub();
+					break;
+				case RETURN:
+					greturn();
+					break;
+				case EXEC:
+					exec_exec();
+					break;
+				case LOAD:
+					exec_load();
+					return 3;
+				case RUN:		// (re)start program at begining
+					ftos = gtos = 0;
+					prog_ip = program;
+					break;
+				case END:		// end program execution
+					return 2;
+			}
+	} while (prog_ip != NULL && tok != FINISHED);
+
+	return 0;
+}
+
+/* display an error message */
+void serror(int error)
+{
+	static char *e[]= {   
+		"syntax error", 
+		"unbalanced parentheses", 
+		"no expression present",
+		"equals sign expected",
+		"not a variable",
+		"Label table full",
+		"duplicate label",
+		"undefined label",
+		"THEN expected",
+		"TO expected",
+		"too many nested FOR loops",
+		"NEXT without FOR",
+		"too many nested GOSUBs",
+		"RETURN without GOSUB"
+	}; 
+	printf ("[near '%s' %d %d] E: %s\n", token, tok, token_type, e[error]);
+
+	longjmp(e_buf, 1); /* return to save point */
+	exit(0);
+
+}
+
+/* Find all labels. */
+void scan_labels()
+{
+	int addr;
+
+	label_init();  /* zero all labels */
+
+	if (program == 0) return;		/* if no program is loaded, nothing to do. */
+
+	prog_ip = program;	/* prog_ip will go through the program */
+
+	/* if the first token in the file is a label */
+	get_token();
+	if(token_type==NUMBER) {
+		strcpy(label_table[0].name,token);
+		label_table[0].p=prog_ip;
+	}
+
+	find_eol();
+	do {     
+		get_token();
+		if(token_type==NUMBER) {
+			addr = get_next_label(token);
+			if(addr==-1 || addr==-2) {
+				(addr==-1) ?serror(5):serror(6);
+			}
+			strncpy(label_table[addr].name, token, LAB_LEN);
+			label_table[addr].name[LAB_LEN-1] = 0;	// null terminate
+			label_table[addr].p = prog_ip;  /* current point in program */
+		}
+		/* if not on a blank line, find next line */
+		if(tok!=EOL) find_eol();
+	} while(tok!=FINISHED);
+}
+
+/* Return index of next free position in label array. 
+   A -1 is returned if the array is full.
+   A -2 is returned when duplicate label is found.
+ */
+int get_next_label(char *s)
+{
+	register int t;
+
+	for(t=0;t<NUM_LAB;++t) {
+		if(label_table[t].name[0]==0) return t;
+		if(!strcmp(label_table[t].name,s)) return -2; /* dup */
+	}
+
+	return -1;
+}
+
+/* Find location of given label.  A null is returned if
+   label is not found; otherwise a pointer to the position
+   of the label is returned.
+ */
+char *find_label(char *s)
+{
+	register int t;
+
+	for(t=0; t<NUM_LAB; ++t) 
+		if(!strcmp(label_table[t].name,s)) return label_table[t].p;
+	return '\0'; /* error condition */
+}
+
+/* Execute a GOTO statement. */
+void exec_goto()
+{
+
+	char *loc;
+
+	get_token(); /* get label to go to */
+	/* find the location of the label */
+	loc = find_label(token);
+	if(loc=='\0')
+		serror(7); /* label not defined */
+
+	else prog_ip=loc;  /* start program running at that loc */
+}
+
+/* Initialize the array that holds the labels. 
+   By convention, a null label name indicates that
+   array position is unused.
+ */
+void label_init()
+{
+	register int t;
+
+	for(t=0; t<NUM_LAB; ++t) label_table[t].name[0]='\0';
+}
+
+/* Execute an IF statement. */
+void exec_if()
+{
+	int x , y, cond;
+	char op;
+
+	get_exp(&x); /* get left expression */
+
+	get_token(); /* get the operator */
+	if(!strchr("=<>", *token)) {
+		serror(0); /* not a legal operator */
+		return;
+	}
+	op=*token;
+
+	get_exp(&y); /* get right expression */
+
+	/* determine the outcome */
+	cond = 0;
+	switch(op) {
+		case '<':
+			if(x<y) cond=1;
+			break;
+		case '>':
+			if(x>y) cond=1;
+			break;
+		case '=':
+			if(x==y) cond=1;
+			break;
+	}
+	if(cond) { /* is true so process target of IF */
+		get_token();
+		if(tok!=THEN) {
+			serror(8);
+			return;
+		}/* else program execution starts on next line */
+	}
+	else find_eol(); /* find start of next line */
+}
+
+/* Execute a FOR loop. */
+void exec_for()
+{
+	struct for_stack i;
+	int value;
+
+	get_token(); /* read the control variable */
+	if(!isalpha(*token)) {
+		serror(4);
+		return;
+	}
+
+	i.var=find_var(token); /* save its index */
+
+	get_token(); /* read the equals sign */
+	if(*token!='=') {
+		serror(3);
+		return;
+	}
+
+	get_exp(&value); /* get initial value */
+
+	*(i.var) = value;
+
+	get_token();
+	if(tok!=TO) serror(9); /* read and discard the TO */
+
+	get_exp(&i.target); /* get target value */
+
+	/* if loop can execute at least once, push info on stack */
+	if(value>=*(i.var)) { 
+		i.loc = prog_ip;
+		fpush(i);
+	}
+	else  /* otherwise, skip loop code altogether */
+		while(tok!=NEXT) get_token();
+}
+
+/* Execute a NEXT statement. */
+void next()
+{
+	struct for_stack i;
+
+	i = fpop(); /* read the loop info */
+
+	(*(i.var))++;
+	if(*(i.var)>i.target) return;  /* all done */
+	fpush(i);  /* otherwise, restore the info */
+	prog_ip = i.loc;  /* loop */
+}
+
+/* Push function for the FOR stack. */
+void fpush(struct for_stack i)
+{
+	if(ftos>FOR_NEST)
+		serror(10);
+
+	fstack[ftos]=i;
+	ftos++;
+}
+
+struct for_stack fpop()
+{
+	ftos--;
+	if(ftos<0) serror(11);
+	return(fstack[ftos]);
+}
+
+/* Execute a GOSUB command. */
+void gosub()
+{
+	char *loc;
+
+	get_token();
+	/* find the label to call */
+	loc = find_label(token);
+	if(loc=='\0')
+		serror(7); /* label not defined */
+	else {
+		gpush(prog_ip); /* save place to return to */
+		prog_ip = loc;  /* start program running at that loc */
+	}
+}
+
+/* Return from GOSUB. */
+void greturn()
+{
+	prog_ip = gpop();
+}
+
+/* GOSUB stack push function. */
+void gpush(char *s)
+{
+	gtos++;
+
+	if(gtos==SUB_NEST) {
+		serror(12);
+		return;
+	}
+
+	gstack[gtos]=s;
+
+}
+
+/* GOSUB stack pop function. */
+char *gpop()
+{
+	if(gtos==0) {
+		serror(13);
+		return 0;
+	}
+
+	return(gstack[gtos--]);
+}
+
+
+/* EXEC function
+	Forks and runs another instance of the interpreter
+ */
+void exec_exec() {
+
+	/* TODO
+	int pid;
+
+	get_token();
+	if (token_type==QUOTE) {
+		pid = fork();
+		if (pid < 0) {
+			printf("Error: could not fork.\n");
+		} else {
+			if (pid == 0) {
+				execlp(interp_name, interp_name, token, 0);
+				printf("Error: could not exec.\n");
+				exit(0);
+			} else {
+				wait(0);
+			}
+		}
+		get_token();
+	} else {
+		serror(0);
+	}
+	*/
+	printf("EXEC not available.\n");
+}
+
+/* LOAD function
+	loads a program into interpreter and ends anything currently executing */
+void exec_load() {
+	char *p_buf;
+
+	get_token();
+	if (token_type==QUOTE) {
+		if (!(p_buf = load_file(token))) {
+			printf("Error: could not load file %s\n", token);
+		} else {
+			load_program(p_buf);
+		}
+	} else {
+		serror(0);
+	}
+}
+
+/* LIST function
+	dumps program source text */
+void exec_list() {
+	get_token();
+
+	if (program == NULL) {
+		printf("No program loaded.\n");
+	} else {
+		printf("%s", program);
+	}
+}