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[as] Add temporaries symbols

These symbols are used for constants in the code and
for folded values. They are freed at the end of every
pass.

--- a/as/as.h

+++ b/as/as.h

@@ -102,6 +102,8 @@

 extern void writeout(char *name);

 extern void emit(Section *sec, char *bytes, int nbytes);

 extern Section *section(char *name);

+extern Symbol *tmpsym(TUINT val);

+extern void killtmp(void);

 /* main.c */

 extern Symbol *lookup(char *name);

--- a/as/expr.c

+++ b/as/expr.c

@@ -14,7 +14,6 @@

 	IDEN = 1,

 	NUMBER,

 	REG,

-	CHAR,

 	STRING,

 	SHL,

 	SHR,

@@ -22,10 +21,16 @@

 	LE,

 };

+union yylval {

+	TUINT val;

+	Symbol *sym;

+};

+

 static Alloc *arena;

 static int yytoken;

 static char yytext[INTIDENTSIZ+1], *textp, *endp;

 static size_t yylen;

+static union yylval yylval;

 #define accept(t) (yytoken == (t) ? next() : 0)

@@ -121,7 +126,7 @@

 	}

 	np = node(NUMBER, l, r);

-	/* np->sym = tmpsym(val); */

+	np->sym = tmpsym(val);

 	return np;

 division_by_zero:

@@ -172,6 +177,9 @@

 	for (endp = textp; isalnum(c = *endp) || c == '_' || c == '.'; ++endp)

 		/* nothing */;

+	tok2str();

+	yylval.sym = lookup(yytext);

+

 	return IDEN;

 }

@@ -183,6 +191,9 @@

 	for (endp = textp; isxdigit(*endp); ++endp)

 		/* nothing */;

+	tok2str();

+	yylval.sym = tmpsym(atoi(yytext));  /* TODO: parse the string */

+

 	return NUMBER;

 }

@@ -194,7 +205,7 @@

 	for (endp = textp+1; *endp != '\''; ++endp)

 		/* nothing */;

-	return CHAR;

+	return NUMBER;

 }

 static int

@@ -261,9 +272,9 @@

 	switch (yytoken) {

 	case NUMBER:

 	case IDEN:

-	case CHAR:

 	case STRING:

 		np = node(yytoken, NULL, NULL);

+		np->sym = yylval.sym;

 		next();

 		break;

 	case '(':

--- a/as/main.c

+++ b/as/main.c

@@ -72,6 +72,13 @@

 	if (fclose(fp))

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

+	if (pass == 2)

+		writeout("a.out");

+	/*

+	 * kill tmp symbols because they are not needed anymore

+	 */

+	killtmp();

+

 	return nerrors == 0;

 }

@@ -89,9 +96,10 @@

 		usage();

 	filename = argv[1];

-	for (pass = 1; pass <= 2 && dopass(filename); pass++)

-		/* nothing */;

-	writeout("a.out");

+	for (pass = 1; pass <= 2; pass++) {

+		if (!dopass(filename))

+			return 1;

+	}

 	return 0;

 }

--- a/as/symbol.c

+++ b/as/symbol.c

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

 #include "as.h"

 #define HASHSIZ 64

+#define NALLOC  10

 static Section abss = {

 	.name  = "abs",

@@ -37,6 +38,8 @@

 int pass;

 static Symbol *hashtbl[HASHSIZ];

+static Alloc *tmpalloc;

+

 Symbol *linesym;

 Symbol *

@@ -199,6 +202,27 @@

 	if (sec->mem)

 		memcpy(&sec->mem[sec->pc - sec->base], bytes, n);

 	incpc(n);

+}

+

+Symbol *

+tmpsym(TUINT val)

+{

+	Symbol *sym;

+

+	if (!tmpalloc)

+		tmpalloc = alloc(sizeof(*sym), NALLOC);

+	sym = new(tmpalloc);

+	sym->value = val;

+	sym->flags = TABS;

+

+	return sym;

+}

+

+void

+killtmp(void)

+{

+	dealloc(tmpalloc);

+	tmpalloc = NULL;

 }

 void