From 9244eacb5ab0b9a11480d1ad40d4720575676877 Mon Sep 17 00:00:00 2001
From: Bobby Bingham <koorogi@koorogi.info>
Date: Tue, 17 Jan 2017 20:14:45 -0600
Subject: nqasm: parse labels

---
 lexer.l  |  5 +++++
 nqasm.c  | 43 +++++++++++++++++++++++++++++++++++++++++++
 nqasm.h  |  1 +
 parser.y | 13 +++++++++++--
 vector.c | 37 +++++++++++++++++++++++++++++++++++++
 vector.h | 13 +++++++++++++
 6 files changed, 110 insertions(+), 2 deletions(-)
 create mode 100644 vector.c
 create mode 100644 vector.h

diff --git a/lexer.l b/lexer.l
index 85021c5..28aa7fe 100644
--- a/lexer.l
+++ b/lexer.l
@@ -2,10 +2,12 @@
 
 #include <errno.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "parser.h"
 
 #define SETVALUE(v) yylval.arg = (struct argument) { .value = (v) }
+#define SETSTR(s)   yylval.str = strdup(s)
 
 static int intlit(const char *s, int base, long *out)
 {
@@ -22,6 +24,7 @@ static int intlit(const char *s, int base, long *out)
 %s inst
 %s args
 
+LABEL      [_a-zA-Z][_a-zA-Z0-9]*
 COMMENT    #[^\n]*
 SP         [ \t]
 EOI        [ \t\n#]
@@ -32,6 +35,8 @@ HEX        [0-9a-f]
 %%
 
 <INITIAL>{SP}+           { BEGIN(inst);    return T_SPACE; }
+<INITIAL>{LABEL}         { SETSTR(yytext); return T_LABEL; }
+<INITIAL>:{SP}*          { BEGIN(inst);    return T_COLON; }
 
 <inst>add/{EOI}          { BEGIN(args);    return T_ADD;    }
 <inst>sub/{EOI}          { BEGIN(args);    return T_SUB;    }
diff --git a/nqasm.c b/nqasm.c
index ed49a48..138407e 100644
--- a/nqasm.c
+++ b/nqasm.c
@@ -6,6 +6,32 @@
 
 #include "lexer.h"
 #include "parser.h"
+#include "vector.h"
+
+struct label {
+	const char *name;
+	uint16_t addr;
+};
+
+static struct labels {
+	struct vector v;
+	struct label l[];
+} *labels;
+
+uint16_t addr;
+
+static int labels_init(void)
+{
+	return !(labels = vector_init(8, sizeof labels->l[0], sizeof *labels));
+}
+
+static struct label *labels_append(void)
+{
+	struct vector *v = &labels->v;
+	struct label  *l = vector_append(&v);
+	labels = (struct labels *)v;
+	return l;
+}
 
 void add_instruction(const struct instruction *inst)
 {
@@ -19,10 +45,27 @@ void add_instruction(const struct instruction *inst)
 	}
 
 	printf("%04x\n", bits);
+	addr += 2;
+}
+
+void add_label(const char *name)
+{
+	struct label *l = labels_append();
+	if (!l) {
+		fprintf(stderr, "unable to allocate label\n");
+		exit(1);
+	}
+
+	*l = (struct label) {
+		.name = name,
+		.addr = addr
+	};
 }
 
 int main(int argc, char **argv)
 {
+	labels_init();
+
 	yyparse();
 	return 0;
 }
diff --git a/nqasm.h b/nqasm.h
index d25911b..232c41b 100644
--- a/nqasm.h
+++ b/nqasm.h
@@ -17,6 +17,7 @@ struct instruction {
 };
 
 void add_instruction(const struct instruction *);
+void add_label(const char *);
 
 #endif
 
diff --git a/parser.y b/parser.y
index 76748de..1f4f5bd 100644
--- a/parser.y
+++ b/parser.y
@@ -29,6 +29,7 @@ void yyerror(const char *msg)
 	struct arguments   args;
 	struct argument    arg;
 	long               lval;
+	char              *str;
 }
 
 %token END 0 "end of file"
@@ -72,12 +73,15 @@ void yyerror(const char *msg)
 %token T_ADDPC
 %token T_NOP
 
+%token <str>  T_LABEL
 %token <lval> T_INT
 %token        T_BADINT
 
 %token <arg> T_REG
 %token <arg> T_REGPTR
+
 %token       T_COMMA    ","
+%token       T_COLON    ":"
 
 %type <inst> inst
 %type <arg>  imm
@@ -98,11 +102,16 @@ input:	line
 	|	input line
 	;
 
-line:	T_SPACE inst eol
-		{ add_instruction(&$2); }
+line:
+		bol inst eol { add_instruction(&$2); }
 	|	eol
 	;
 
+bol:
+		T_SPACE
+	|	T_LABEL ":"  { add_label($1); }
+	;
+
 inst:
 		T_ADD    a_reg3      { $$ = INSTRUCTION_ARGS(ADD,    $2); }
 	|	T_SUB    a_reg3      { $$ = INSTRUCTION_ARGS(SUB,    $2); }
diff --git a/vector.c b/vector.c
new file mode 100644
index 0000000..57f62d7
--- /dev/null
+++ b/vector.c
@@ -0,0 +1,37 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "vector.h"
+
+#define VECTOR_TOOBIG(alloc,elemsize,arrayoff)    ((SIZE_MAX - (arrayoff)) / (alloc) < (elemsize))
+#define VECTOR_ALLOCSIZE(alloc,elemsize,arrayoff) ((arrayoff) + (alloc) * (elemsize))
+
+void *vector_init(size_t alloc, size_t elemsize, size_t arrayoff)
+{
+	if (VECTOR_TOOBIG(alloc, elemsize, arrayoff)) return NULL;
+	struct vector *v = malloc(VECTOR_ALLOCSIZE(alloc, elemsize, arrayoff));
+	if (!v) return NULL;
+
+	*v = (struct vector) {
+		.alloc    = alloc,
+		.elemsize = elemsize,
+		.arrayoff = arrayoff,
+	};
+	return v;
+}
+
+void *vector_append(struct vector **vp)
+{
+	struct vector *v = *vp;
+	if (v->count >= v->alloc) {
+		size_t alloc = 2 * v->alloc;
+		if (VECTOR_TOOBIG(alloc, v->elemsize, v->arrayoff)) return NULL;
+		v = realloc(v, VECTOR_ALLOCSIZE(alloc, v->elemsize, v->arrayoff));
+		if (!v) return NULL;
+		v->alloc = alloc;
+		*vp = v;
+	}
+	return (char*)v + v->arrayoff + v->count++ * v->elemsize;
+}
+
diff --git a/vector.h b/vector.h
new file mode 100644
index 0000000..fb32da7
--- /dev/null
+++ b/vector.h
@@ -0,0 +1,13 @@
+#ifndef NQ_VECTOR_H
+#define NQ_VECTOR_H
+
+#include <stddef.h>
+
+struct vector {
+	size_t alloc, count, elemsize, arrayoff;
+};
+
+void *vector_init(size_t alloc, size_t elemsize, size_t arrayoff);
+void *vector_append(struct vector **vp);
+
+#endif
-- 
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