M projects/06/Makefile → projects/06/Makefile

@@ -2,7 +2,6 @@ 
 CFLAGS = -std=c99 -Wall -Wextra
 
 all: bin/assembler1
-#all: bin/assembler1 bin/bin2text
 
 # TODO: clean up, make more Makefile-idiomatic
 

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

@@ -4,21 +4,37 @@ #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "../bindump.h"
-
-//#define DEBUG(...)              printf(__VA_ARGS__)
-#define DEBUG(...)
-#define die(err_msg)            perror(err_msg); exit(-1)
+//#define DBGLOG(...)             printf(__VA_ARGS__)
+#define DBGLOG(...)
 #define error(...)              fprintf(stderr, __VA_ARGS__); \
                                 fprintf(stderr, "%lu | %s\n", \
                                         g_asm_line_number, g_asm_line);
 
 #define MAX_LINE_LEN            256
 
-char *g_asm_line;             // copy of currently-read line for easy reference
-size_t g_asm_line_number;     // current line number
+char *g_asm_line;                 // currently-read line for convenience
+size_t g_asm_line_number;         // current line number
+size_t g_instruction_number = 0;  // instruction offset
 
 
+void print_binary_word16(uint16_t w)
+{
+        unsigned char i, msb;
+        char binary_string[17];
+        binary_string[16] = '\0';
+
+        for (i = 0; i < 16; ++i) {
+                msb = (char)(w >> 15);
+
+                if (msb != 0)
+                        binary_string[i] = '1';
+                else
+                        binary_string[i] = '0';
+                w <<= 1;
+        }
+        printf("%s", binary_string);
+}
+
 static uint32_t myatoi(const char *a_field_str)
 {
 	size_t i;
@@ -33,9 +49,11 @@ }
 
 static bool parse_a_type(const char *line, uint16_t *instruction)
 {
-	char c, a_field_str[6];  // TODO: eventually factor out use of array
+	char c, a_field_str[6];
 	uint32_t a_field = 0;
 	size_t i, a = 0;
+
+	DBGLOG("line: %s\n", comp_line);
 
 	if (line[0] != '@') {
 		error("syntax error: A-type instruction doesn't start with @\n");
@@ -64,25 +82,25 @@ return false;
 		}
 	}
 
-	a_field_str[a] = '\0';   // exit
+	a_field_str[a] = '\0';
 
-	// TODO: extension: support negative numbers
-	a_field = myatoi(a_field_str);
+	a_field = myatoi(a_field_str);  // TODO: maybe negative number support?
 	if (a_field > 32767) {
 		error("error: %u > 32767, too large\n", a_field);
 		return false;
 	}
 
 	*instruction = 0x0000 | (uint16_t) a_field;
-	return true; // STUB, A-type MSB == 0 anyway
+	return true;
 }
 
 /* returns dest bits 0b00000ddd
+ * Note: order doesn't matter for multi-register dest (but officially it should)
  */
 static bool parse_c_type_dest(const char *dest_line, uint8_t *dest)
 {
 	size_t len;
-	DEBUG("dest_line: %s\n", dest_line);
+	DBGLOG("dest_line: %s\n", dest_line);
 
 	for (len = 0; dest_line[len] != '='; ++len) {  // read until '='
 		if (dest_line[len] == 'A') {
@@ -124,12 +142,11 @@ return true;
 }
 
 /* returns comp bits 0b0acccccc
- * TODO: refactor (especially the error cases, which are too repetitive)
  */
 static bool parse_c_type_comp(const char *comp_line, uint8_t *comp)
 {
 	size_t len;
-	DEBUG("comp_line: %s\n", comp_line);
+	DBGLOG("comp_line: %s\n", comp_line);
 
 	for (len = 0; comp_line[len] == '0' || comp_line[len] == '1' ||
 	              comp_line[len] == '-' || comp_line[len] == 'D' ||
@@ -240,9 +257,9 @@ */
 static bool parse_c_type_jump(const char *jump_line, uint8_t *jump)
 {
 	size_t len;
-	char *err_1st_char = "syntax error: jump field doesn't start with 'J'\n";
-	char *err_2nd_char = "syntax error: 2nd letter in jump field incorrect\n";
 	char *err_3rd_char = "syntax error: 3rd letter in jump field incorrect\n";
+
+	DBGLOG("jump_line: %s\n", dest_line);
 
 	for (len = 0; jump_line[len] == 'J' || jump_line[len] == 'G' ||
 	              jump_line[len] == 'T' || jump_line[len] == 'E' ||
@@ -296,11 +313,11 @@ error(err_3rd_char); return false;
 			}
 			break;
 		default:
-			error(err_2nd_char);
+			error("syntax error: 2nd letter in jump field incorrect\n");
 			return false;
 		}
 	} else {
-		error(err_1st_char);
+		error("syntax error: jump field doesn't start with 'J'\n");
 		return false;
 	}
 
@@ -313,7 +330,7 @@ * TODO: eventually just replace all wasteful c-instruction parsing w/ strcmp()
  */
 static bool parse_c_type(const char *line, uint16_t *instruction)
 {
-	bool ret;
+	bool ret = false;
 	char c;
 	const char *dest_start = NULL;
 	const char *comp_start = NULL;
@@ -384,7 +401,7 @@ // does not care about line line length; exits at first newline or after
 // relevant portion parsed (allows for syntactically-incorrect lines, I know)
 static bool parse_next_instruction(const char *line, uint16_t *instruction)
 {
-	bool ret;
+	bool ret = false;
 	char c;
 	size_t i = 0;
 
@@ -393,9 +410,11 @@ if (c == ' ' || c == '\t')
 			;  // skip any whitespace at start of line
 		else if (c == '@') {
 			ret = parse_a_type(&line[i], instruction);
+			++g_instruction_number;
 			break;
 		} else if (c >= '!' && c < '~') {
 			ret = parse_c_type(&line[i], instruction);
+			++g_instruction_number;
 			break;
 		} else {
 			error("syntax error: line '%s' incorrectly formatted\n",
@@ -409,36 +428,29 @@ return ret;
 }
 
 // return false for comment or invalid assembly instruction
-bool parse_line(const char *line, size_t line_len, uint16_t *instruction)
+bool parse_line(const char *line, uint16_t *instruction)
 {
 	char c;
 	bool slash_found = false;
 	size_t i;
 
-	if (line_len == 0 || line_len == 1)
-		return false;
-
 	// filter out comment lines
-	//for (i = 0; (c = line[i]) != NULL; ++i) {
-	for (i = 0; i < line_len; ++i) {
-		c = line[i];
-
+	for (i = 0; (c = line[i]) != '\0'; ++i) {
 		if (c == ' ' || c == '\t') {
 			continue;
+		} else if (i == 0 && c == '\0') {
+			return false;
 		} else if (c == '/') {
-			if (slash_found) {
-				// second slash means this is a comment
+			if (slash_found) {    // second slash means comment
 				return false;
 			}
 			slash_found = true;
 			continue;
 		} else if (slash_found) {
 			// this char not slash, but previous was: invalid syntax
-			// TODO: add line, column numbers
 			error("syntax error: found '/', comments need '//'\n");
 			return false;
-		} else {
-			// non-whitespace/slash char discovered
+		} else {                      // non-whitespace/slash discovered
 			break;
 		}
 	}
@@ -452,12 +464,10 @@ char *usage_msg = "Usage: assembler1 [path/to/file.asm]\n";
 
 int main(int argc, char *argv[])
 {
-	DEBUG("DEBUG 1 2 3...\n");
-
 	bool result = false; 
 	uint16_t instruction;
 	char in_line[MAX_LINE_LEN];
-	size_t in_line_len, i, file_line;
+	size_t i, file_line, in_line_len;
 	char *in_file_path;
 	FILE *fp;
 
@@ -473,27 +483,34 @@ fprintf(stderr, "failed to open file for reading\n");
 		exit(-1);
 	}
 
-	file_line = 1;
+	file_line = 0;
 	while (fgets(in_line, MAX_LINE_LEN, fp) != NULL) {  // parse loop
-		in_line_len = strlen(in_line);
+		++file_line;
 
-		for (i = 0; i < in_line_len; ++i) { // remove newlines
-			if (in_line[i] == '\n') {   // TODO handle DOS '\r\n'
+		for (i = 0; in_line[i] != '\0'; ++i) {      // remove newlines
+			if (in_line[i] == '\n' || in_line[i] == '\r') {
 				in_line[i] = '\0';
 				break;
 			}
+			++in_line_len;
 		}
 
-		DEBUG("%lu|%s | ", file_line, in_line);
+		if (in_line_len == 0 || in_line_len == 1)
+			continue;
+
 		g_asm_line = in_line;
 		g_asm_line_number = file_line;
-		result = parse_line(in_line, in_line_len, &instruction);
+		result = parse_line(in_line, &instruction);
+
 		if (result) {
-			DEBUG("instruction: 0x%x | ", instruction);
-			bindump_word16(instruction); // output instruction as binary
+			print_binary_word16(instruction);
 			putchar('\n');
 		}
-	++file_line;
+	}
+
+	if (fclose(fp)) {
+		fprintf(stderr, "Failed to close file %s\n", in_file_path);
+		exit(-1);
 	}
 
 	return 0;

D projects/06/bindump.h

@@ -1,21 +0,0 @@ 
-#include <stdio.h>
-#include <stdint.h>
-
-void bindump_word16(uint16_t w)
-{
-	unsigned char i, msb;
-	char binary_string[17];
-	binary_string[16] = '\0';
-
-	for (i = 0; i < 16; ++i) {
-		msb = (char)(w >> 15);
-
-		if (msb != 0)
-			binary_string[i] = '1';
-		else
-			binary_string[i] = '0';
-		w <<= 1;
-	}
-	printf("%s", binary_string);
-}
-