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Save and restore decompiler stack state at jump targets #33

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691a6dd
Save and restore decompiler stack state at jump targets
NeoDement May 23, 2026
0513eef
added 'cursor image room ' fix
NeoDement Jun 3, 2026
4c871ea
self-parenthesize so each formula is one token
NeoDement Jun 3, 2026
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29 changes: 26 additions & 3 deletions src/nutcracker/sputm/windex_v6.py
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Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,8 @@ def __repr__(self):
'or': 11,
}

ARITH_OPS = frozenset('+-*/%') # self-parenthesize so each formula is one token


class BinExpr:
def __init__(self, op, left, right):
Expand Down Expand Up @@ -204,6 +206,7 @@ def __repr__(self):
or isinstance(left, Negate)
or (
isinstance(left, BinExpr)
and left.op not in ARITH_OPS
and left.pre >= self.pre
and left.op != self.op
)
Expand All @@ -215,11 +218,14 @@ def __repr__(self):
or isinstance(right, Negate)
or (
isinstance(right, BinExpr)
and right.op not in ARITH_OPS
and right.pre >= self.pre
and right.op != self.op
)
):
right = f'({right})'
if self.op in ARITH_OPS:
return f'({left} {self.op} {right})'
return f'{left} {self.op} {right}'


Expand Down Expand Up @@ -2406,9 +2412,10 @@ def o6_cursorCommand(op, stack, game):
if game.he_version >= 70 or game.version >= 7:
# TODO: Figure out object?
return f'cursor {stack.pop()}'
# TODO: another pop for non HE or HE < 70 games
image = stack.pop()
return f'cursor {stack.pop()} image {image}'
# Non-HE / HE<70 (v6): setCursorFromImg(obj, room). ScummVM popRoomAndObj pops
# room first, then obj; emit obj first so this reads 'cursor image <obj> room <room>'.
room = stack.pop()
return f'cursor image {stack.pop()} room {room}'
elif cmd.num == 0x9A:
ypos = stack.pop()
xpos = stack.pop()
Expand Down Expand Up @@ -5799,6 +5806,10 @@ def decompile_script(elem, game, verbose=False, transform=True):
asts = deque()
res = None

# Stack state tracking for proper control flow handling
# Maps jump target addresses to saved stack states
saved_stacks = {}

# # clear local variables:
# for key in g_vars: # NOTE: dict key is tuple, we iterates on keys only
# _, var = key
Expand Down Expand Up @@ -5840,6 +5851,7 @@ def decompile_script(elem, game, verbose=False, transform=True):
yield f'\tverb {entries[off + 8]} {{'
indent = 2 * '\t'
stack.clear()
saved_stacks.clear()
if verbose:
yield ' '.join(
[
Expand All @@ -5850,6 +5862,11 @@ def decompile_script(elem, game, verbose=False, transform=True):
)
if isinstance(res, ConditionalJump) or isinstance(res, UnconditionalJump):
srefs.add(off)

# Restore saved stack state at jump targets
if off in saved_stacks:
stack = deque(saved_stacks[off])

stack_backup = list(stack)
try:
res = ops.get(stat.name, defop)(stat, stack, game)
Expand All @@ -5870,6 +5887,12 @@ def decompile_script(elem, game, verbose=False, transform=True):
# # '\t\t\t\t',
# # defop(stat, stack, bytecode),
# )

# Save stack state for jump targets
if isinstance(res, (ConditionalJump, UnconditionalJump)):
target = res.ref.abs
if target not in saved_stacks:
saved_stacks[target] = list(stack)
yield from print_locals(indent)
l_vars.clear()
yield from print_asts(
Expand Down