From 543a435b9f526580e51a336c74a4f8e5551b62ab Mon Sep 17 00:00:00 2001
From: Ryan Houdek <Sonicadvance1@gmail.com>
Date: Fri, 2 Jan 2026 21:35:12 -0800
Subject: [PATCH] unittests/ASM: Adds test for flags clobber in
 `TelemetrySetValue`

Showcases the bug that #5192 fixed. This would have failed prior to that
PR's change.
---
 .../32Bit_ASM/FEX_bugs/TelemetryFlags.asm     | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 unittests/32Bit_ASM/FEX_bugs/TelemetryFlags.asm

diff --git a/unittests/32Bit_ASM/FEX_bugs/TelemetryFlags.asm b/unittests/32Bit_ASM/FEX_bugs/TelemetryFlags.asm
new file mode 100644
index 000000000..cdc7ba29e
--- /dev/null
+++ b/unittests/32Bit_ASM/FEX_bugs/TelemetryFlags.asm
@@ -0,0 +1,38 @@
+%ifdef CONFIG
+{
+  "RegData": {
+    "RAX": "0x0000000000011000",
+    "RCX": "0x0000000051529654",
+    "RDX": "0x0000000061626303"
+  },
+  "Mode": "32BIT"
+}
+%endif
+
+; FEX-Emu had a bug with its `TelemetrySetValue` IR operation where it would corrupt host flags at an inopportune time.
+; The IR operation does `cmp+cset`, but even with `ImplicitFlagClobber` set, this happened at a invalid time for flag handling.
+; To test this:
+;  - btr -> Sets CF
+;  - adc with `ss:` -> Adds to register with carry, but `ss:` causes `TelemetrySetValue`.
+;  - Host flags are corrupted after the `TelemetrySetValue`, before the `adc` was able to operate.
+
+mov ecx, 0x51525354
+mov edx, 0x61626303
+
+lea eax, [.data]
+lea esp, [.data_flags]
+popf
+
+and word [eax], dx
+btr cx, dx
+adc cx, ss:[eax]
+
+hlt
+
+align 4096
+
+.data:
+dd 0x41424344
+
+.data_flags:
+dd 0xfeff