@@ -5,5 +5,5 @@ *.out
 
 # ignore prokect 05 machine code files, project 06 test files, build artifacts
 projects/05/*.hack
-projects/06/bin/*
+projects/*/bin/*
 

@@ -0,0 +1,15 @@ 
+# nand2tetris chapter 6 VM translator makefile
+# for debugging this makefile: `make -d`
+CFLAGS = -std=c99 -Wall -Wextra
+
+all: bin/vmtranslator
+
+# TODO: clean up, make more Makefile-idiomatic
+
+bin/vmtranslator: src/vmtranslator.c
+	$(CC) $(CFLAGS) -o $@ $<
+
+clean:
+	rm -vf bin/*
+
+.PHONY: clean

@@ -0,0 +1,3 @@ 
+
+# Virtual Machine I: Processing
+

@@ -0,0 +1,27 @@ 
+#ifndef _CODEWRITER_H
+#define _CODEWRITER_H
+
+// 'parser.h' roughly corresponds to the 'Parser' module specified in
+// nand2tetris, with a few liberties taken.
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "parser.h"
+
+#define DBGLOG   printf
+//#define DBGLOG(...)
+#define MAX_LINE_LEN    256  // TODO need to be redefined here? (remove me)
+
+
+bool write_instruction(struct vm_instruction_t *vm_instr, FILE *fp)
+{
+	// TODO implement
+	// STUB!
+	return true;
+}
+
+#endif // _CODEWRITER_H

@@ -0,0 +1,62 @@ 
+#ifndef _PARSER_H
+#define _PARSER_H
+
+// 'parser.h' roughly corresponds to the 'Parser' module specified in
+// nand2tetris, with a few liberties taken.
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define DBGLOG   printf
+//#define DBGLOG(...)
+#define MAX_LINE_LEN    256  // TODO need to be redefined here? (remove me)
+
+enum vm_command_t {
+	C_ARITHMETIC,
+	C_PUSH,
+	C_POP,
+	C_LABEL,
+	C_GOTO,
+	C_IF,
+	C_FUNCTION,
+	C_RETURN,
+	C_CALL
+};
+
+struct vm_instruction_t {
+	enum vm_command_t cmd;
+	char *arg1;
+	uint16_t arg2;
+	const char *original_vm_line;
+};
+
+
+bool parse_command_type(struct vm_instruction_t *vm_instr) {
+	return true; // STUB TODO implement
+}
+
+bool parse_arg1(struct vm_instruction_t *vm_instr) {
+	return true; // STUB TODO implement
+}
+
+bool parse_arg2(struct vm_instruction_t *vm_instr) {
+	return true; // STUB TODO implement
+}
+
+bool parse_line(const char *line, struct vm_instruction_t *vm_instr)
+{
+	vm_instr->original_vm_line = line;
+	DBGLOG("// %s\n", vm_instr->original_vm_line);
+	if (!parse_command_type(vm_instr))
+		return false;
+	if (!parse_arg1(vm_instr))
+		return false;
+	if (!parse_arg2(vm_instr))
+		return false;
+	return true;
+}
+
+#endif // _PARSER_H

@@ -0,0 +1,113 @@ 
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "parser.h"
+#include "codewriter.h"
+
+#define _DEBUG
+
+#ifdef _DEBUG
+#define DBGLOG   printf
+#else
+#define DBGLOG(...)
+#endif
+
+#define err(...) (fprintf(stderr, __VA_ARGS__), \
+                  fprintf(stderr, "%lu | %s\n", file_line_no, file_line), false)
+#define die(...)   do { fprintf(stderr, __VA_ARGS__); exit(-1); } while (0)
+
+#define is_symbol_char(c) (('0' <= c && c <= '9') || ('A' <= c && c <= 'Z') \
+                        || ('a' <= c && c <= 'z') || c == '_' || c == '.'   \
+                                                  || c == '$' || c == ':')
+#define is_whitespace(c) ((c == ' ' || c == '\t' || c == '\n' || c == '\r'))
+#define is_number(c) (('0' <= c && c <= '9'))
+
+#define MAX_LINE_LEN          256 // TODO: in/excludes NULL terminator?
+#define MAX_SYMBOL_LEN        MAX_LINE_LEN - 2 + 1 // + 1 for NULL terminator
+
+char  *file_line;     // reference to currently-read line (for convenience)
+size_t file_line_no;  // line number, regardless of line content
+
+
+static size_t skip_whitespace(const char *line, size_t n)
+{
+	size_t i;
+	for (i = 0; is_whitespace(line[i]) && i < n; ++i);
+	return i;
+}
+
+bool translate(FILE *in_file)
+{
+	char *line, in_line[MAX_LINE_LEN], *translated;
+	struct vm_instruction_t vm_instr;
+	size_t i, line_len;
+
+	file_line_no = 0;
+	//instruction_offset = 0; // TODO: unnecessary?
+	while (fgets(in_line, MAX_LINE_LEN, in_file) != NULL) {  // parse loop
+		++file_line_no;
+		file_line = in_line;
+		line = &in_line[skip_whitespace(in_line, MAX_LINE_LEN)];
+
+		line_len = 0;
+		for (i = 0; line[i] != '\0'; ++i) {
+			if (line[i] == '\n' || line[i] == '\r') {
+				line[i] = '\0'; // remove newlines
+				break;
+			}
+			++line_len;  // get line length
+		}
+
+		if (line_len == 0)  // "empty" line
+			continue;
+		if (line_len > 1) {
+			if (line[0] == '/' && line[1] == '/') {  // if comment
+				continue;
+			} else {
+				// parser will error specifically (TODO remove me)
+				if (!parse_line(line, &vm_instr))
+					return false;
+				if (!write_instruction(&vm_instr, in_file))
+					return false;
+			}
+		}
+	}
+
+	return true;
+}
+
+
+char *usage_msg = "Usage: vmtranslator [input/file.vm] [translated/output]\n"
+                  "       vmtranslator [input/file.vm]  # output to STDOUT\n";
+
+int main(int argc, char *argv[])
+{
+	FILE *in_file, *out_file;
+	if (argc == 2) {
+		out_file = stdout;
+	} else if (argc == 3) {
+		out_file = fopen(argv[2], "wb");
+		if (out_file == NULL)
+			die("failed to open %s for writing\n", argv[2]);
+	} else {
+		die(usage_msg);
+	}
+
+	in_file = fopen(argv[1], "r"); // read input file
+	if (in_file == NULL)
+		die("failed to open %s for reading\n", argv[1]);
+
+	if(!translate(in_file)) // first pass
+		die("failed to translate VM code in file\n");
+
+	if (fclose(in_file))
+		die("failed to close VM file\n");
+	if (fclose(out_file))
+		die("failed to close assembly output file\n");
+
+	return 0;
+}
+

@@ -0,0 +1,31 @@ 
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/07/MemoryAccess/BasicTest/BasicTest.vm
+
+// Executes pop and push commands using the virtual memory segments.
+push constant 10
+pop local 0
+push constant 21
+push constant 22
+pop argument 2
+pop argument 1
+push constant 36
+pop this 6
+push constant 42
+push constant 45
+pop that 5
+pop that 2
+push constant 510
+pop temp 6
+push local 0
+push that 5
+add
+push argument 1
+sub
+push this 6
+push this 6
+add
+sub
+push temp 6
+add

@@ -0,0 +1,22 @@ 
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/07/MemoryAccess/PointerTest/PointerTest.vm
+
+// Executes pop and push commands using the 
+// pointer, this, and that segments.
+push constant 3030
+pop pointer 0
+push constant 3040
+pop pointer 1
+push constant 32
+pop this 2
+push constant 46
+pop that 6
+push pointer 0
+push pointer 1
+add
+push this 2
+sub
+push that 6
+add

@@ -0,0 +1,17 @@ 
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/07/MemoryAccess/StaticTest/StaticTest.vm
+
+// Executes pop and push commands using the static segment.
+push constant 111
+push constant 333
+push constant 888
+pop static 8
+pop static 3
+pop static 1
+push static 3
+push static 1
+sub
+push static 8
+add

@@ -0,0 +1,9 @@ 
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/07/StackArithmetic/SimpleAdd/SimpleAdd.vm
+
+// Pushes and adds two constants.
+push constant 7
+push constant 8
+add

@@ -0,0 +1,45 @@ 
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/07/StackArithmetic/StackTest/StackTest.vm
+
+// Executes a sequence of arithmetic and logical operations
+// on the stack. 
+push constant 17
+push constant 17
+eq
+push constant 17
+push constant 16
+eq
+push constant 16
+push constant 17
+eq
+push constant 892
+push constant 891
+lt
+push constant 891
+push constant 892
+lt
+push constant 891
+push constant 891
+lt
+push constant 32767
+push constant 32766
+gt
+push constant 32766
+push constant 32767
+gt
+push constant 32766
+push constant 32766
+gt
+push constant 57
+push constant 31
+push constant 53
+add
+push constant 112
+sub
+neg
+and
+push constant 82
+or
+not