From 1bd2ff3fc347a69db38ca6dbdf5bb35ff356e7e2 Mon Sep 17 00:00:00 2001
From: Billy Laws <blaws05@gmail.com>
Date: Wed, 29 Apr 2026 02:16:57 +0000
Subject: [PATCH] unittests/ASM: Adds test for FSCALE(0, +Inf) raising IE

---
 unittests/ASM/FEX_bugs/FSCALE_zero_inf.asm | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 unittests/ASM/FEX_bugs/FSCALE_zero_inf.asm

diff --git a/unittests/ASM/FEX_bugs/FSCALE_zero_inf.asm b/unittests/ASM/FEX_bugs/FSCALE_zero_inf.asm
new file mode 100644
index 000000000..4c942d57b
--- /dev/null
+++ b/unittests/ASM/FEX_bugs/FSCALE_zero_inf.asm
@@ -0,0 +1,30 @@
+%ifdef CONFIG
+{
+  "RegData": {
+    "RBX":  "0x0001"
+  }
+}
+%endif
+
+; FSCALE(+0, +Inf) is 0 * 2^(+Inf) = 0 * Inf, which must raise the invalid
+; operation exception (IE=1).
+
+mov r15, 0xe0000000
+fninit
+
+mov dword [r15 + 0], 0x00000000
+mov dword [r15 + 4], 0x7ff00000
+
+fld qword [r15 + 0]
+fldz
+
+fscale
+
+fstp qword [r15 + 16]
+fstp st0
+
+fnstsw ax
+movzx rbx, ax
+and rbx, 1
+
+hlt