M projects/06/assembler1/assembler1.c → projects/06/assembler1/assembler1.c

@@ -26,48 +26,39 @@ }
 
 bool parse_a_type(const char *line, uint16_t *instruction)
 {
-	bool num_found = false;
 	char c, a_field_str[6];  // TODO: eventually factor out use of array
 	uint32_t a_field = 0;
 	size_t i, a = 0;
 
-	i = 0;
-	while ((c = line[i]) != '\n') {
-		if (c == ' ' || c == '\t' || c == '/') {
-			if (num_found) {
-				num_found = false;
-				if (a < 7) {
-					a_field_str[a] = '\0';
-					break;
-				} else {
-					die("fatal error: a-type value index "
-					    "%lu out of range\n", -1);
-				}
-			} else {
-				;  // skip whitespace
-			}
-		} else if (num_found) {
-			if ('0' <= c && c <= '9') {
-				if (a > 4) {
-					alert("error: @<number> too long\n");
-					return false;
-				}
-				a_field_str[a] = c; // get number
-			} else {
-				alert("syntax error: invalid char '%c' found "
-				      "after @\n", c);
+	if (line[0] != '@') {
+		alert("error: A-type instruction doesn't start with @\n");
+		return false;
+	}
+
+	if (line[1] == '\n') {
+		alert("error: A-type instruction empty after @\n");
+		return false;
+	}
+
+	for (i = 1; (c = line[i]) != '\n' && a < 6; ++i) {
+		if ('0' <= c && c <= '9') {
+			if (a > 4) {
+				alert("error: @<number> too long\n");
 				return false;
 			}
-			++a;
-		} else if (c == '@') {
-			a = 0;
-			num_found = true;
-		} else {
-			alert("syntax error: invalid char '%c' before @\n", c);
+			a_field_str[a] = c; // get number
+			a++;
+		} else if ((c == ' ' || c == '\t' || c == '/') && i > 1) {
+			break;
+		} else {       // any other character
+			alert("syntax error: invalid char '%c' found after @\n",
+			      c);
 			return false;
 		}
-		++i;
 	}
+
+	a_field_str[a] = '\0';   // exit
+
 	// TODO: extension: support negative numbers
 	a_field = myatoi(a_field_str);
 	if (a_field > 32767) {
@@ -81,9 +72,8 @@ }
 
 bool parse_c_type(const char *line, uint16_t *instruction)
 {
-	DEBUG("parse_c_type()\n");
-	*instruction = 0x8000; // STUB, C-type MSB == 1 anyway
-	return true; // STUB, C-type MSB == 1 anyway
+	*instruction = 0x8888; // STUB, TODO implement
+	return true;
 }
 
 // does not care about line line length; exits at first newline or after
@@ -96,12 +86,12 @@ size_t i = 0;
 
 	while ((c = line[i]) != '\n') {
 		if (c == ' ' || c == '\t')
-			;  // skip whitespace
+			;  // skip any whitespace at start of line
 		else if (c == '@') {
-			ret = parse_a_type(line, instruction);
+			ret = parse_a_type(&line[i], instruction);
 			break;
 		} else if (c >= '!' && c < '~') {
-			ret = parse_c_type(line, instruction);
+			ret = parse_c_type(&line[i], instruction);
 			break;
 		} else {
 			alert("syntax error: line '%s' incorrectly formatted\n",
@@ -161,9 +151,16 @@ "@98 // test comment\n",                // line 5
                             "// this is another comment\n",         // line 6
                             "/ this is a broken comment\n",         // line 7
                             "D=M;JNE\n",                            // line 8
-			    " @1337// immediate comment \n",        // line 9
-			    "\t@13371337 // number too long \n",    // line 10
-			    "    @0x1337 // invalid char in num\n"}; // line 11
+			    "   @1337// immediate comment \n",      // line 9
+			    "\t@44441337 // number too long \n",    // line 10
+			    " \t @1     // 1\n",                    // line 11
+			    "\t @2      // 2\n",                    // line 12
+			    "\t @3\n",                              // line 13
+			    "\t @4\n",                              // line 14
+			    " \t@5      // 3\n",                    // line 15
+			    "    @6     // 4\n",                    // line 16
+			    "\t @7\n",                              // line 17
+			    "    @0x1337 // invalid char in num\n"}; // line 18
 size_t num_test_lines = (sizeof(test_lines) / sizeof(test_lines[0]));
 
 int main()