diff options
Diffstat (limited to 'src/assembler.py')
| -rwxr-xr-x | src/assembler.py | 57 |
1 files changed, 38 insertions, 19 deletions
diff --git a/src/assembler.py b/src/assembler.py index 9e2d92f..5802983 100755 --- a/src/assembler.py +++ b/src/assembler.py @@ -45,7 +45,7 @@ def parse(line: str) -> list[str]: def eval_expr(expr: str) -> int: expr = eval_symbol(expr) - return eval(expr, labels) # eval as Python expr + return eval(expr, labels.copy()) # eval as Python expr def eval_symbol(c: str): if c in labels: @@ -85,7 +85,7 @@ labels: dict[str, int] = {} address = 0 for (lineNo, line) in enumerate(src_lines): - line = line.strip() + line = line.split(";")[0].strip() if line == "": continue keyword, *args = line.lower().split() match keyword: @@ -98,8 +98,6 @@ for (lineNo, line) in enumerate(src_lines): address += 1 -print("labels:", labels) - # 2nd pass address = 0 @@ -122,33 +120,50 @@ for (lineNo, line) in enumerate(src_lines): # Instructions case "alu": + # S (alu op) + # L (lhs) + # R (rhs) + # T (target) word = (0b0000 << 12) + \ - (eval_expr(args[0]) << 9) + \ - (eval_expr(args[1]) << 6) + \ - (eval_expr(args[2]) << 3) + \ + (eval_expr(args[0]) << 3) + \ + (eval_expr(args[1]) << 9) + \ + (eval_expr(args[2]) << 6) + \ (eval_expr(args[3]) << 0) case "als": + # S (alu op) + # L (lhs) + # R (rhs) + # T (target) word = (0b0001 << 12) + \ - (eval_expr(args[0]) << 9) + \ - (eval_expr(args[1]) << 6) + \ - (eval_expr(args[2]) << 3) + \ + (eval_expr(args[0]) << 3) + \ + (eval_expr(args[1]) << 9) + \ + (eval_expr(args[2]) << 6) + \ (eval_expr(args[3]) << 0) case "ldr": + # R (address) + # T (target) word = (0b0010 << 12) + \ (eval_expr(args[0]) << 9) + \ - (eval_expr(args[1]) << 6) + (eval_expr(args[1]) << 0) case "str": + # R (address) + # T (value to store) word = (0b0011 << 12) + \ (eval_expr(args[0]) << 9) + \ (eval_expr(args[1]) << 6) case "ldi": + # T (target) + # I (immediate) word = (0b0100 << 12) + \ - (eval_expr(args[0]) << 9) + \ - (eval_expr(args[1]) << 0) + (eval_expr(args[0]) << 0) + \ + (eval_expr(args[1]) << 3) case "jmp": + # R (reg holding address) word = (0b0101 << 12) + \ (eval_expr(args[0]) << 9) case "br": + # F (flag selector) + # R (reg holding address) word = (0b0110 << 12) + \ (eval_expr(args[0]) << 9) + \ (eval_expr(args[1]) << 6) @@ -160,20 +175,20 @@ for (lineNo, line) in enumerate(src_lines): 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) + (eval_expr("al_a_plus_b") << 3) + \ + (eval_expr(args[2]) << 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) + (eval_expr("al_a_minus_b") << 3) + \ + (eval_expr(args[2]) << 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) + (eval_expr("al_a_plus_b") << 3) + \ + (eval_expr(args[1]) << 0) # Default case: evaluate as is (e.g. data word) case _: @@ -185,6 +200,10 @@ for (lineNo, line) in enumerate(src_lines): if len(result) < 2 * address + 1: result.extend((2 * address + 1 - len(result)) * nop) + for (label, label_addr) in labels.items(): + if address == label_addr: + print(f"{label}:") + print(f"{address:>08x} 0x{word:>04x} {line}") result[2 * address + 0] = ((word >> 8) & 0xff) result[2 * address + 1] = ((word >> 0) & 0xff) |