Add solutions for part 1

projects/06/assembler.py

@@ -0,0 +1,201 @@
+#!/usr/bin/env python3
+
+import sys
+import re
+
+
+
+def preprocess(lines):
+    lines = remove_whitespaces(lines)
+    lines = replace_symbols(lines)
+    return lines
+
+
+def replace_symbols(lines):
+    symbols = {
+        "SP": "0",
+        "LCL": "1",
+        "ARG": "2",
+        "THIS": "3",
+        "THAT": "4",
+        "R0": "0",
+        "R1": "1",
+        "R2": "2",
+        "R3": "3",
+        "R4": "4",
+        "R5": "5",
+        "R6": "6",
+        "R7": "7",
+        "R8": "8",
+        "R9": "9",
+        "R10": "10",
+        "R11": "11",
+        "R12": "12",
+        "R13": "13",
+        "R14": "14",
+        "R15": "15",
+        "SCREEN": "16384",
+        "KBD": "24576",
+        }
+
+    # Find all labels, remove them, and add them to symbol table.
+    address = 0
+    re_label = re.compile("\((\S*)\)")
+    lines_without_labels = []
+    for line in lines:
+        m = re_label.match(line)
+        if m:
+            label = m.groups()[0]
+            if label in symbols:
+                raise Exception("Multiple defines for {}.".format(line))
+            symbols[label] = str(address)
+        else:
+            lines_without_labels.append(line)
+            address += 1
+    lines = lines_without_labels
+
+    # Find all address instruction and replace symbols.
+    lines_without_symbols = []
+    re_symbol = re.compile("@([A-Za-z]\S*)")
+    address = 16
+    for line in lines:
+        m = re_symbol.match(line)
+        if m:
+            symbol = m.groups()[0]
+            if symbol in symbols:
+                symbol_value = symbols[symbol]
+            else:
+                symbol_value = str(address)
+                symbols[symbol] = symbol_value
+                address += 1
+            lines_without_symbols.append("@" + symbol_value)
+        else:
+            lines_without_symbols.append(line)
+    return lines_without_symbols
+
+
+def assemble(lines):
+    lines = assemble_instructions(lines)
+    return lines
+
+
+def remove_whitespaces(lines):
+    r_whitespace = re.compile("\s")
+    r_comment = re.compile("//.*")
+    lines = [r_whitespace.sub("", line) for line in lines]
+    lines = [r_comment.sub("", line) for line in lines]
+    return [line for line in lines if line]
+
+
+def assemble_instructions(lines):
+    return [assemble_instruction(line) for line in lines]
+
+
+def assemble_instruction(line):
+    if line.startswith("@"):
+        return assemble_a_instruction(line)
+    else:
+        return assemble_c_instruction(line)
+
+
+def assemble_a_instruction(line):
+    adr_str = line.replace("@", "")
+    adr_int = int(adr_str)
+    adr_bin_str = bin(adr_int)[2:]
+    adr_bin_str = "0" * (16 - len(adr_bin_str)) + adr_bin_str
+    return adr_bin_str
+
+
+def assemble_c_instruction(line):
+    r = re.compile("(\S+)=(\S+);(\S+)")
+    if not ";" in line:
+        line = line + ";null"
+    if not "=" in line:
+        line = "null=" + line
+    dest, comp, jump = r.match(line).groups()
+    ins_str = "111" + comp_lookup(comp) + dest_lookup(dest) + jump_lookup(jump)
+    return ins_str
+
+def comp_lookup(comp_str):
+    return {
+        "0":   "0101010",
+        "1":   "0111111",
+        "-1":  "0111010",
+        "D":   "0001100",
+        "A":   "0110000",
+        "M":   "1110000",
+        "!D":  "0001101",
+        "!A":  "0110001",
+        "!M":  "1110001",
+        "-D":  "0001111",
+        "-A":  "0110011",
+        "-M":  "1110011",
+        "D+1": "0011111",
+        "A+1": "0110111",
+        "M+1": "1110111",
+        "D-1": "0001110",
+        "A-1": "0110010",
+        "M-1": "1110010",
+        "D+A": "0000010",
+        "D+M": "1000010",
+        "D-A": "0010011",
+        "D-M": "1010011",
+        "A-D": "0000111",
+        "M-D": "1000111",
+        "D&A": "0000000",
+        "D&M": "1000000",
+        "D|A": "0010101",
+        "D|M": "1010101"
+    }[comp_str]
+
+
+def dest_lookup(dest_str):
+    return {
+        "null": "000",
+        "M":    "001",
+        "D":    "010",
+        "MD":   "011",
+        "A":    "100",
+        "AM":   "101",
+        "AD":   "110",
+        "AMD":  "111"
+    }[dest_str]
+
+
+def jump_lookup(jump_str):
+    return {
+        "null": "000",
+        "JGT":  "001",
+        "JEQ":  "010",
+        "JGE":  "011",
+        "JLT":  "100",
+        "JNE":  "101",
+        "JLE":  "110",
+        "JMP":  "111"
+    }[jump_str]
+
+
+if __name__ == "__main__":
+    try:
+        hack_asm_file = sys.argv[1]
+        if not hack_asm_file.endswith(".asm"):
+            sys.exit("Hack asm file must have a .asm file ending.")
+        hack_asm_ns_file = hack_asm_file.replace(".asm", ".nosymbol.asm")
+        hack_bin_file = hack_asm_file.replace(".asm", ".hack")
+    except IndexError:
+        sys.exit("Call: ./assembler.py <hack_asm_file>")
+
+    with open(hack_asm_file, 'r') as f:
+        assembly_lines = f.readlines()
+
+    preprocessed_lines = preprocess(assembly_lines)
+    binary_lines = assemble(preprocessed_lines)
+
+    with open(hack_asm_ns_file, 'w') as f:
+        for line in preprocessed_lines:
+            f.write(line + "\n")
+
+    with open(hack_bin_file, 'w') as f:
+        for line in binary_lines:
+            f.write(line + "\n")
+