1 files changed, 41 insertions, 20 deletions
diff --git a/nandgame/assembler/disas.py b/nandgame/assembler/disas.py
index 0256976..1a3ae33 100755
--- a/nandgame/assembler/disas.py
+++ b/nandgame/assembler/disas.py
@@ -12,7 +12,8 @@ import sys
 ZERO = "#0"
 DEST_NONE = "_"
 JUMP_NONE = ""
-
+JUMPS_IF_NZERO = ["jgt", "jlt", "jne", "jmp"]
+JUMPS_IF_ZERO = ["jge", "jle", "jeq", "jmp"]
 
 def decode_jump(ins: int) -> str:
     if (ins & 0x7) == 0:
@@ -133,25 +134,45 @@ def decode_instruction(ins: int) -> list[str]:
 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]
-
-    # 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", "", "", "", ""]
-    if mnemonic == "and" and op1 == ZERO:
-        if jumpdest in ["jgt", "jlt", "jne", JUMP_NONE]:
-            newjmp = ""
-        else:
-            newjmp = "jmp"
-        return ["mov", dest, ZERO, "", newjmp]
+    if op1 == ZERO:
+        # subtract something from #0 - subtraction
+        if  mnemonic == "sub":
+            return ["neg", dest, op2, "", jumpdest]
+
+        # 0 AND something = 0
+        if mnemonic == "and":
+            # if no dest, only jump matters
+            if dest == DEST_NONE:
+                # jump always or jump-if-zero --> always jump
+                if jumpdest in JUMPS_IF_ZERO:
+                    return ["jmp", "", "", "", ""]
+                # all other jumps? <, >, <>, nojmp
+                else:
+                    return ["nop", "", "", "", ""]
+            else:
+                if jumpdest in JUMPS_IF_ZERO:
+                    newjmp = "jmp"
+                else:
+                    newjmp = ""
+                return ["mov", dest, ZERO, "", newjmp]
+
+        # 0 +/|/^ something = something
+        if mnemonic in ["add", "or", "xor"]:
+            if dest == DEST_NONE and jumpdest == JUMP_NONE:
+                return ["nop", "", "", "", ""]
+            else:
+                return ["mov", dest, op2, "", jumpdest]
+
+        # basically, not 0 == 0xFFFF....
+        # opposite of what AND is doing?
+        if mnemonic == "not":
+            # if no dest, only jump matters
+            if dest == DEST_NONE:
+                # 0xFFFF is not jgt, since highest bit is always signed.
+                if jumpdest in ["jeq", "jgt", "jge", JUMP_NONE]:
+                    return ["nop", "", "", "", ""]
+                else:
+                    return ["jmp", "", "", "", ""]
 
     return [mnemonic, dest, op1, op2, jumpdest]