Canonicalize ops

1 files changed, 40 insertions, 12 deletions

diff --git a/nandgame/assembler/disas.py b/nandgame/assembler/disas.py
index cabdcdd..607537a 100755
--- a/nandgame/assembler/disas.py
+++ b/nandgame/assembler/disas.py
@@ -11,11 +11,13 @@ import sys
 
 ZERO = "#0"
 DEST_NONE = "_"
+JUMP_NONE = ""
 
 
 def decode_jump(ins: int) -> str:
     if (ins & 0x7) == 0:
-        return ""
+        return JUMP_NONE
+
     if (ins & 0x7) == 0x7:
         return "jmp"
 
@@ -111,7 +113,7 @@ def decode_dest(ins: int) -> str:
     return dest if dest else DEST_NONE
 
 
-def decode_instruction_complete(ins: int) -> list[str]:
+def decode_instruction(ins: int) -> list[str]:
     """
     Will return a 5 element list/tuple/whatever
     mnemonic, destination, X, Y, jumpdest
@@ -120,27 +122,45 @@ def decode_instruction_complete(ins: int) -> list[str]:
         # mov? ldr? ldi? aaaaaaaaaaa....
         return ["mov", "A", f"#{ins}", "", ""]
     else:
-        codename, two_op = decode_ins(ins)
+        mnemonic, two_op = decode_ins(ins)
         dest = decode_dest(ins)
         op1 = decode_arg1(ins)
         op2 = decode_arg2(ins) if two_op else ""
         jumpdest = decode_jump(ins)
+        return [mnemonic, dest, op1, op2, jumpdest]
+
 
-        # fixups
-        if op1 == ZERO and codename == "sub":
-            return ["neg", dest, op2, "", jumpdest]
+def fixup_ins(ins: int) -> list[str]:
+    (mnemonic, dest, op1, op2, jumpdest) = decode_instruction(ins)
+    # fixups
+    # subtract something from #0 - subtraction
+    if op1 == ZERO and mnemonic == "sub":
+        return ["neg", dest, op2, "", jumpdest]
 
-        return [codename, dest, op1, op2, jumpdest]
+    # 0 AND something = 0
+    # if no dest, only jump matters
+    if mnemonic == "and" and op1 == ZERO and dest == DEST_NONE:
+        # jump always or jump-if-zero --> always jump
+        if jumpdest in ["jgt", "jlt", "jne", JUMP_NONE]:
+            return ["nop", "", "", "", ""]
+        # all other jumps? <=, >=, =, <=>
+        else:
+            return ["jmp", "", "", "", ""]
 
+    return [mnemonic, dest, op1, op2, jumpdest]
 
-def print_decoded(ins: int) -> str:
-    (codename, dest, op1, op2, jumpdest) = decode_instruction_complete(ins)
+
+def print_decoded(ins: int, simplify: bool) -> str:
+    if simplify:
+        (mnemonic, dest, op1, op2, jumpdest) = fixup_ins(ins)
+    else:
+        (mnemonic, dest, op1, op2, jumpdest) = decode_instruction(ins)
 
     jumpdest_str = f".{jumpdest}" if jumpdest else ""
-    opcode_str = f"{codename}{jumpdest_str}"
+    opcode_str = f"{mnemonic}{jumpdest_str}"
     dest_str = f"{dest}, " if dest else 7 * " "
     op1_str = f"{op1}{", " if op2 else ""}"
-    return f"{opcode_str:<9}{dest_str:<6}{op1_str:<4}{op2:<5}"
+    return f"{opcode_str:<9}{dest_str:<6}{op1_str:<4}{op2}"
 
 
 def main():
@@ -156,7 +176,15 @@ def main():
                 if not insb:
                     break
                 ins = int.from_bytes(insb)
-                print(f"\t{insb[0]:02x} {insb[1]:02x}\t{print_decoded(ins)}")
+                raw_ins = f"{insb[0]:02x} {insb[1]:02x}"
+                decoded_ins = print_decoded(ins, False)
+                decoded_ins2 = print_decoded(ins, True)
+                if decoded_ins == decoded_ins2:
+                    line = f"\t{raw_ins}\t{decoded_ins}"
+                else:
+                    line = f"\t{raw_ins}\t{decoded_ins2:<25}; {decoded_ins}"
+
+                print(line)
 
     except FileNotFoundError:
         print(f"File {filename} not found.")