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https://github.com/RetroPortingToolKit/psxrecomp
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Matthew Stanley
e54e63131c
When a `beq+delay-slot` terminator's delay-slot address is also a basic-block
label (target of an external `b BFCxxxx` from a sibling branch), the previously
emitted C placed the variable declaration BEFORE the next block label and the
dangling if-goto AFTER it:
label_BFC2185C:
capture brA, brB
int psx_taken_BFC2185C = (brA == brB); // declaration
label_BFC21860: // goto target
cpu->gpr[1] = ...; // delay-slot c_code
if (psx_taken_BFC2185C) goto label_BFC21800; // ← dangling
When control reaches `label_BFC21860` via a goto from elsewhere (e.g., the
COPY branch ends with `b 0xbfc21860`), C semantics make `psx_taken_BFC2185C`
indeterminate because its declaration with initializer was skipped. On MinGW,
stack garbage is non-zero → the if-goto fires unconditionally → spurious
cross-branch jump → infinite loop in DELETE branch (BFC21800).
Concretely this caused the memcard COPY confirm-modal freeze: pressing CROSS
on a save-block target should push widget 0xA modal, but the COPY branch
would push 0xA correctly, then on `b 0xbfc21860` cleanup the dangling
if-goto would fire spuriously and jump into the DELETE branch, which keeps
re-pushing widget 0xB and reverting state.
Fix: in the first pass, collect every branch terminator address and emit
`int psx_taken_BFCxxxx = 0;` at function entry. Change the terminator-emit
from declaration to assignment. Now external gotos that bypass the
assignment see the zero default and the dangling if-goto correctly does
not fire.
Regenerated `generated/SCPH1001_full.c`: 6083 zero-init declarations,
all `int psx_taken_*` at terminator sites converted to assignments.
User-verified: COPY confirm-modal now appears. (YES/NO button/close
behavior still broken — likely additional bugs in the same class or
adjacent codegen edge cases; tracked separately.)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>