From 3e2ba6d835c28137e36376b7e9bebade4dad4609 Mon Sep 17 00:00:00 2001
From: Ryan Houdek <Sonicadvance1@gmail.com>
Date: Sat, 2 Dec 2023 13:02:12 -0800
Subject: [PATCH] unittests/ASM: Adds test for TestNZ bug

Would trigger the bug before it was fixed.
---
 unittests/ASM/FEX_bugs/ShiftConstantBug.asm | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 unittests/ASM/FEX_bugs/ShiftConstantBug.asm

diff --git a/unittests/ASM/FEX_bugs/ShiftConstantBug.asm b/unittests/ASM/FEX_bugs/ShiftConstantBug.asm
new file mode 100644
index 000000000..99ad3b314
--- /dev/null
+++ b/unittests/ASM/FEX_bugs/ShiftConstantBug.asm
@@ -0,0 +1,15 @@
+%ifdef CONFIG
+{
+  "RegData": {
+    "RAX": "0x500000020"
+  }
+}
+%endif
+
+; FEX had a bug in its `TestNZ` opcode where it would try to load a constant in to the tst instruction
+; If the constant didn't fit in a logical encoding it would generate invalid instructions and also crash.
+; This snippet of code was found in libGLX.so.0.0.0 when trying to load steamwebhelper.
+mov     eax, 0x28000001
+shl     rax, 0x5
+
+hlt