1 files changed, 263 insertions, 0 deletions
diff --git a/src/assembler.py b/src/assembler.py
new file mode 100755
index 0000000..9e2d92f
--- /dev/null
+++ b/src/assembler.py
@@ -0,0 +1,263 @@
+#!/usr/bin/env python3
+# Assemble ATK16 assembly to bytecode
+
+import sys
+
+if len(sys.argv) != 3:
+  print("usage: assembler.py <infile> <outfile> # read from file")
+  print("       assembler.py - <outfile>        # read from stdin")
+  sys.exit(1)
+
+infile_path = sys.argv[1]
+outfile_path = sys.argv[2]
+
+src = ""
+if (infile_path == "-"):
+  for line in sys.stdin:
+    src += line
+else:
+  with open(infile_path, "r") as f:
+    src = f.read()
+
+src_lines = src.splitlines()
+
+### Utils
+
+def parse(line: str) -> list[str]:
+  depth = 0
+  result = []
+  acc = ""
+  for c in line:
+    if c.isspace() and depth == 0:
+      result.append(acc)
+      acc = ""
+    elif c == "(":
+      depth += 1
+      acc += "("
+    elif c == ")":
+      depth -= 1
+      acc += ")"
+    else:
+      acc += c
+
+  result.append(acc)
+  return list(filter(lambda x: len(x) > 0, result))
+
+def eval_expr(expr: str) -> int:
+  expr = eval_symbol(expr)
+  return eval(expr, labels) # eval as Python expr
+
+def eval_symbol(c: str):
+  if c in labels:
+    return str(labels[c])
+
+  match c:
+    # Registers
+    case "rz": return "0"
+    case "ra": return "1"
+    case "rb": return "2"
+    case "rc": return "3"
+    case "rd": return "4"
+    case "pa": return "5"
+    case "pb": return "6"
+    # ALU instructions
+    case "al_clear": return "0"
+    case "al_b_minus_a": return "1"
+    case "al_a_minus_b": return "2"
+    case "al_a_plus_b": return "3"
+    case "al_a_xor_b": return "4"
+    case "al_a_or_b": return "5"
+    case "al_a_and_b": return "6"
+    case "al_preset": return "7"
+    case "al_logical_shift_right": return "8"
+    case "al_arithmetic_shift_right": return "9"
+    case "al_logical_shift_left": return "10"
+    # ALU flags
+    case "f_carry": return "0"
+    case "f_overflow": return "1"
+    case "f_zero": return "2"
+    case "f_sign": return "3"
+    case _: return c
+
+# 1st pass, gather labels
+
+labels: dict[str, int] = {}
+address = 0
+
+for (lineNo, line) in enumerate(src_lines):
+  line = line.strip()
+  if line == "": continue
+  keyword, *args = line.lower().split()
+  match keyword:
+    case "@address":
+      address = eval(args[0])
+      continue
+    case "@label":
+      labels[args[0]] = address
+      continue
+
+  address += 1
+
+print("labels:", labels)
+
+# 2nd pass
+
+address = 0
+nop = bytearray([0b1000_0000, 0])
+result = bytearray()
+# initially one nop
+result.extend(nop)
+
+for (lineNo, line) in enumerate(src_lines):
+  line = line.split(";")[0].strip()
+  if line == "": continue
+  keyword, *args = parse(line.lower())
+  match keyword:
+    # Directives
+    case "@address":
+      address = eval_expr(args[0])
+      continue
+    case "@label":
+      continue
+
+    # Instructions
+    case "alu":
+      word = (0b0000 << 12) + \
+             (eval_expr(args[0]) << 9) + \
+             (eval_expr(args[1]) << 6) + \
+             (eval_expr(args[2]) << 3) + \
+             (eval_expr(args[3]) << 0)
+    case "als":
+      word = (0b0001 << 12) + \
+             (eval_expr(args[0]) << 9) + \
+             (eval_expr(args[1]) << 6) + \
+             (eval_expr(args[2]) << 3) + \
+             (eval_expr(args[3]) << 0)
+    case "ldr":
+      word = (0b0010 << 12) + \
+             (eval_expr(args[0]) << 9) + \
+             (eval_expr(args[1]) << 6)
+    case "str":
+      word = (0b0011 << 12) + \
+             (eval_expr(args[0]) << 9) + \
+             (eval_expr(args[1]) << 6)
+    case "ldi":
+      word = (0b0100 << 12) + \
+             (eval_expr(args[0]) << 9) + \
+             (eval_expr(args[1]) << 0)
+    case "jmp":
+      word = (0b0101 << 12) + \
+             (eval_expr(args[0]) << 9)
+    case "br":
+      word = (0b0110 << 12) + \
+             (eval_expr(args[0]) << 9) + \
+             (eval_expr(args[1]) << 6)
+    case "hlt":
+      word = 0b1111 << 12
+
+    # Pseudoinstructions
+    case "add":
+      word = (0b0000                   << 12) + \
+             (eval_expr(args[0])       << 9) + \
+             (eval_expr(args[1])       << 6) + \
+             (eval_expr(args[2])       << 3) + \
+             (eval_expr("al_a_plus_b") << 0)
+    case "sub":
+      word = (0b0000                    << 12) + \
+             (eval_expr(args[0])        << 9) + \
+             (eval_expr(args[1])        << 6) + \
+             (eval_expr(args[2])        << 3) + \
+             (eval_expr("al_a_minus_b") << 0)
+    case "mov":
+      word = (0b0000                   << 12) + \
+             (eval_expr("rz")          << 9) + \
+             (eval_expr(args[0])       << 6) + \
+             (eval_expr(args[1])       << 3) + \
+             (eval_expr("al_a_plus_b") << 0)
+
+    # Default case: evaluate as is (e.g. data word)
+    case _:
+      try:
+        word = eval_expr(keyword)
+      except:
+        raise Exception(f"Invalid assembly at {infile_path}:{lineNo + 1}\n\n{line}")
+
+  if len(result) < 2 * address + 1:
+    result.extend((2 * address + 1 - len(result)) * nop)
+
+  print(f"{address:>08x}  0x{word:>04x}  {line}")
+  result[2 * address + 0] = ((word >> 8) & 0xff)
+  result[2 * address + 1] = ((word >> 0) & 0xff)
+  address += 1
+
+with open(outfile_path, "wb") as f:
+  f.write(result)
+
+print(f"Wrote {len(result)} bytes to {outfile_path}")
+
+with open(f"{outfile_path}.logisim.txt", "w") as f:
+  f.write("v2.0 raw\n")
+  run_length = 0
+  run_last = ""
+  for i in range(len(result) // 2):
+    b0 = result[2 * i + 0]
+    b1 = result[2 * i + 1]
+    word = f"{b0:>02x}{b1:>02x}\n"
+
+    if word != run_last and run_length <= 1:
+      f.write(f"{run_last}")
+      run_length = 1
+      run_last = word
+    elif word != run_last and run_length > 1:
+      f.write(f"{run_length}*{run_last}")
+      run_length = 1
+      run_last = word
+    else:
+      run_length += 1
+
+  if run_length <= 1:
+    f.write(f"{run_last}")
+  else:
+    f.write(f"{run_length}*{run_last}")
+
+print(f"Wrote Logisim image format to {outfile_path}.logisim.txt")
+
+with open(f"{outfile_path}.ver.txt", "w") as f:
+  f.write("addr/data: 15 16")
+  run_length = 0
+  run_last = ""
+  written = -1
+
+  def update_layout():
+    if run_last == "": return
+    if written % 8 == 0:
+      f.write("\n")
+    else:
+      f.write(" ")
+
+  for i in range(len(result) // 2):
+    b0 = result[2 * i + 0]
+    b1 = result[2 * i + 1]
+    word = f"{b0:>02x}{b1:>02x}"
+
+    if word != run_last and run_length <= 1:
+      f.write(f"{run_last}")
+      run_length = 1
+      run_last = word
+      written += 1
+      update_layout()
+    elif word != run_last and run_length > 1:
+      f.write(f"{run_length}*{run_last}")
+      run_length = 1
+      run_last = word
+      written += 1
+      update_layout()
+    else:
+      run_length += 1
+
+  if run_length <= 1:
+    f.write(f"{run_last}")
+  else:
+    f.write(f"{run_length}*{run_last}")
+
+print(f"Wrote verification test format to {outfile_path}.ver.txt")