diff --git a/CMakeLists.txt b/CMakeLists.txt
index 54c3be4..7b260ff 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,6 +6,7 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
 # Source files
 file(GLOB LIB_SOURCES       "src/lib/*.c")
+file(GLOB AS_SOURCES        "src/as/*.c")
 file(GLOB EMU_SOURCES       "src/emu/*.c")
 
 # Library for shared code
@@ -13,8 +14,11 @@ add_library(lc3tools ${LIB_SOURCES})
 target_include_directories(lc3tools PUBLIC include)
 
 # Executables
+add_executable(lc3as ${AS_SOURCES})
 add_executable(lc3emu ${EMU_SOURCES})
+target_include_directories(lc3as PRIVATE include/as)
 target_include_directories(lc3emu PRIVATE include/emu)
 
 # Link shared code and executables
+target_link_libraries(lc3as lc3tools)
 target_link_libraries(lc3emu lc3tools)
diff --git a/include/as/lc3as.h b/include/as/lc3as.h
new file mode 100644
index 0000000..38d0e26
--- /dev/null
+++ b/include/as/lc3as.h
@@ -0,0 +1,6 @@
+#ifndef __LC3AS_H
+#define __LC3AS_H
+
+#define LC3AS_TEST 6969
+
+#endif /* __LC3AS_H */
diff --git a/include/lc3tools.h b/include/lc3tools.h
index 69c8cd2..09e068d 100644
--- a/include/lc3tools.h
+++ b/include/lc3tools.h
@@ -28,6 +28,8 @@
  */
 #define DEBUG 1
 
+#define TEST_DIR    "../test"
+
 /*
  * File separator character.
  */
diff --git a/src/as/main.c b/src/as/main.c
new file mode 100644
index 0000000..bf119b5
--- /dev/null
+++ b/src/as/main.c
@@ -0,0 +1,123 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <lc3as.h>
+#include <lc3tools.h>
+
+#define LINE_BUFFER_SIZE 256
+
+struct source_file
+{
+    FILE *file;
+    char line[LINE_BUFFER_SIZE];
+    size_t line_len;
+    size_t line_num;
+    size_t line_pos;
+};
+
+int read_line(struct source_file *src)
+{
+    src->line_num++;
+    if (feof(src->file) || fgets(src->line, LINE_BUFFER_SIZE, src->file) == 0)
+    {
+        return -1;
+    }
+
+    src->line_len = strlen(src->line);
+    src->line_pos = 0;
+
+    return src->line_len;
+}
+
+int read_token(struct source_file *src, char **tok, char delim)
+{
+    size_t i;
+    // char *tok;
+    char *tok_head;
+    char *tok_tail;
+    char c;
+    int char_seen;
+
+    if (src->line_pos >= src->line_len)
+    {
+        return 0;
+    }
+
+    tok_head = &src->line[src->line_pos];
+    tok_tail = tok_head;
+    i = 0;
+    char_seen = 0;
+
+    while ((c = tok_head[i]) != '\0')
+    {
+        src->line_pos++;
+        if (isspace(c))
+        {
+            if (!char_seen)
+            {
+                tok_head++;
+                tok_tail++;
+                continue;
+            }
+            else if (c == '\n')
+            {
+                *tok_tail = '\0';
+                *tok = tok_head;
+                return 1;
+            }
+            else if (!isspace(delim))
+            {
+                i++;
+                continue;
+            }
+        }
+
+        char_seen = 1;
+        if (c == delim)
+        {
+            *tok_tail = '\0';
+            *tok = tok_head;
+            return 1;
+        }
+        i++;
+        tok_tail++;
+    }
+
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    struct source_file src;
+    char *tok;
+
+    memset(&src, 0, sizeof(struct source_file));
+    src.file = fopen(TEST_DIR"/astest2.asm", "rb");
+    if (src.file == NULL)
+    {
+        return 2;
+    }
+
+    while (read_line(&src) != -1)
+    {
+        read_token(&src, &tok, ' ');
+        // read_token(&src, &tok, '\t');
+
+        printf("tok: %s\n", tok);
+        if (strcasecmp(tok, "ADD") == 0)
+        {
+            printf("ADD\n");
+            while ((read_token(&src, &tok, ',')) != 0)
+            {
+                printf("'%s'\n", tok);
+            }
+        }
+    }
+
+    printf("Hit end of file! (line %zu)\n", src.line_num);
+    fclose(src.file);
+
+    return 0;
+}
\ No newline at end of file