Nicer disas output

- move jump in instruction
- have better zero args
- canocicalize some instructions

1 files changed, 13 insertions, 4 deletions

diff --git a/nandgame/assembler/disas.py b/nandgame/assembler/disas.py
index f7669c0..cabdcdd 100755
--- a/nandgame/assembler/disas.py
+++ b/nandgame/assembler/disas.py
@@ -9,6 +9,9 @@ I don't like the "C-style" one nandgame introduces.
 
 import sys
 
+ZERO = "#0"
+DEST_NONE = "_"
+
 
 def decode_jump(ins: int) -> str:
     if (ins & 0x7) == 0:
@@ -74,7 +77,7 @@ def decode_arg1(ins: int) -> str:
     sw = (ins & (1 << 6)) != 0
 
     if zx:
-        return "#0"
+        return ZERO
     if not sw:
         return "D"
     return "M" if use_mem else "A"
@@ -105,7 +108,7 @@ def decode_dest(ins: int) -> str:
     if dM:
         dest += "M"
 
-    return dest if dest else "_"
+    return dest if dest else DEST_NONE
 
 
 def decode_instruction_complete(ins: int) -> list[str]:
@@ -122,16 +125,22 @@ def decode_instruction_complete(ins: int) -> list[str]:
         op1 = decode_arg1(ins)
         op2 = decode_arg2(ins) if two_op else ""
         jumpdest = decode_jump(ins)
+
+        # fixups
+        if op1 == ZERO and codename == "sub":
+            return ["neg", dest, op2, "", jumpdest]
+
         return [codename, dest, op1, op2, jumpdest]
 
 
 def print_decoded(ins: int) -> str:
     (codename, dest, op1, op2, jumpdest) = decode_instruction_complete(ins)
 
+    jumpdest_str = f".{jumpdest}" if jumpdest else ""
+    opcode_str = f"{codename}{jumpdest_str}"
     dest_str = f"{dest}, " if dest else 7 * " "
     op1_str = f"{op1}{", " if op2 else ""}"
-    jumpdest_str = f"; {jumpdest}" if jumpdest else ""
-    return f"{codename:<5}{dest_str:<6}{op1_str:<4}{op2:<5}{jumpdest_str}"
+    return f"{opcode_str:<9}{dest_str:<6}{op1_str:<4}{op2:<5}"
 
 
 def main():