shithub: scc

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[as] Add parser.c

Split the content of main.c between main control flow and parsing
functions.

--- a/as/Makefile

+++ b/as/Makefile

@@ -4,7 +4,7 @@

 include ../config.mk

 include $(LIBDIR)/libdep.mk

-OBJ = main.o emit.o ins.o

+OBJ = main.o emit.o ins.o parser.o

 HDR = ../inc/scc.h as.h

 all:

@@ -16,7 +16,6 @@

 $(LIBDIR)/libscc.a:

 	cd $(LIBDIR) && $(MAKE)

-

 dep:

 	./gendep.sh $(TARGETS)

--- a/as/as.h

+++ b/as/as.h

@@ -22,6 +22,12 @@

 typedef void Format(Op *, Arg *);

 typedef struct section Section;

+struct line {

+	char *label;

+	char *op;

+	char *args;

+};

+

 struct ins {

 	int begin, end;

 	char *str;

@@ -57,6 +63,13 @@

 extern Section *section(char *name);

 extern void incpc(int siz);

 extern char *pack(TUINT v, int n, int inc);

+extern void error(char *msg, ...);

+extern Arg *getargs(char *s);

+

+/* Avoid errors in files where stdio is not included */

+#ifdef stdin

+extern int next(FILE *fp, struct line *linep);

+#endif

 extern Section *cursec;

 extern int nr_ins;

--- a/as/main.c

+++ b/as/main.c

@@ -1,5 +1,4 @@

-#include <ctype.h>

 #include <stdarg.h>

 #include <stdio.h>

 #include <stdlib.h>

@@ -8,9 +7,6 @@

 #include "../inc/scc.h"

 #include "as.h"

-#define MAXLINE 100

-#define NARGS 20

-

 int nerrors;

 void

@@ -40,60 +36,7 @@

 	return 1;

 }

-Arg

-number(char *s, int base)

-{

-	Arg arg;

-	TUINT n;

-

-	/* TODO: Check overflow here */

-	arg.type = AIMM;

-	for (n = 0; *s; n += *s++ - '0')

-		n *= base;

-	arg.val = n;

-

-	return arg;

-}

-

-Arg *

-getargs(char *s)

-{

-	char *t;

-	int ch, len;

-	Arg *ap;

-	static Arg args[NARGS];

-

-	for (ap = args; s; ++ap) {

-		while (isspace(*s))

-			++s;

-		if (*s == '\0')

-			break;

-		if (ap == &args[NARGS-1])

-			die("too many arguments in one instruction");

-

-		for (t = s; *s && *s != ','; s++)

-			/* nothing */;

-		len = t - s;

-		if (len == 0)

-			goto wrong_operand;

-

-		if (*s)

-			*s++ = '\0';

-

-		ch = *t;

-		if (isdigit(ch)) {

-			*ap = number(t, (s[len-1] == 'H') ? 16 : 10);

-			continue;

-		}

-wrong_operand:

-		error("wrong operand '%s'", t);

-	}

-	ap->type = 0;

-

-	return args;

-}

-

-void

+void

 incpc(int siz)

 {

 	TUINT pc, curpc;

@@ -145,54 +88,20 @@

 }

 int

-extract(char *p, char **lbl, char **ins, char **args)

+dopass(char *fname)

 {

-	*lbl = p;

-	*ins = NULL;

-	*args = NULL;

+	struct line line;

+	FILE *fp;

-	if ((p = strchr(p, '\t')) == NULL)

-		return 0;

-	*p++ = '\0';

+	if ((fp = fopen(fname, "r")) == NULL)

+		die("as: error opening '%s'", fname);

-	*ins = p;

-	if ((p = strchr(p, '\t')) == NULL)

-		return 1;

-	*p++ = '\0';

-

-	*args = p;

-	if ((p = strchr(p, '\t')) == NULL)

-		return 2;

-	*p = '\0';

-	return 3;

-}

-

-int

-dopass(char *file)

-{

-	FILE *in;

-	char line[MAXLINE], *ins, *lbl, *args;

-

-	if ((in = fopen(file, "r")) == NULL)

-		die("error opening '%s'", file);

-

 	isections();

+	while (next(fp, &line))

+		as(line.op, line.args);

-	while (fgets(line, sizeof(line), in)) {

-		size_t n = strlen(line);

-		if (n == 0 || line[0] == ';')

-			continue;

-		if (line[n-1] != '\n') {

-			error("line too long");

-			continue;

-		}

-		line[n-1] = '\0';

-		if (extract(line, &lbl, &ins, &args) > 0)

-			as(ins, args);

-	}

-

-	if (fclose(in))

-		die("error reading from input file");

+	if (fclose(fp))

+		die("as: error reading from input file '%s'", fname);

 	return nerrors == 0;

 }

--- /dev/null

+++ b/as/parser.c

@@ -1,0 +1,109 @@

+#include <ctype.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>

+

+#include "../inc/scc.h"

+#include "as.h"

+

+#define NARGS 20

+#define MAXLINE 100

+

+

+Arg

+number(char *s, int base)

+{

+	Arg arg;

+	TUINT n;

+

+	/* TODO: Check overflow here */

+	arg.type = AIMM;

+	for (n = 0; *s; n += *s++ - '0')

+		n *= base;

+	arg.val = n;

+

+	return arg;

+}

+

+Arg *

+getargs(char *s)

+{

+	char *t;

+	int ch, len;

+	Arg *ap;

+	static Arg args[NARGS];

+

+	for (ap = args; s; ++ap) {

+		while (isspace(*s))

+			++s;

+		if (*s == '\0')

+			break;

+		if (ap == &args[NARGS-1])

+			die("too many arguments in one instruction");

+

+		for (t = s; *s && *s != ','; s++)

+			/* nothing */;

+		len = t - s;

+		if (len == 0)

+			goto wrong_operand;

+

+		if (*s)

+			*s++ = '\0';

+

+		ch = *t;

+		if (isdigit(ch)) {

+			*ap = number(t, (s[len-1] == 'H') ? 16 : 10);

+			continue;

+		}

+wrong_operand:

+		error("wrong operand '%s'", t);

+	}

+	ap->type = 0;

+

+	return args;

+}

+

+int

+extract(char *p, struct line *linep)

+{

+	linep->label = p;

+	linep->op = NULL;

+	linep->args = NULL;

+

+	if ((p = strchr(p, '\t')) == NULL)

+		return 0;

+	*p++ = '\0';

+

+	linep->op = p;

+	if ((p = strchr(p, '\t')) == NULL)

+		return 1;

+	*p++ = '\0';

+

+	linep->args = p;

+	if ((p = strchr(p, '\t')) == NULL)

+		return 2;

+	*p = '\0';

+	return 3;

+}

+

+int

+next(FILE *fp, struct line *linep)

+{

+	size_t n;

+	static char buff[MAXLINE];

+

+repeat:

+	if (!fgets(buff, sizeof(buff), fp))

+		return 0;

+

+	n = strlen(buff);

+	if (n == 0 || buff[0] == ';')

+		goto repeat;

+	if (buff[n-1] != '\n') {

+		error("buff too long");

+		goto repeat;

+	}

+	buff[n-1] = '\0';

+	if (extract(buff, linep) == 0)

+		goto repeat;

+}