diff --git a/regress/reg_write_sign_extension.py b/regress/reg_write_sign_extension.py
new file mode 100644
index 00000000..69347c0f
--- /dev/null
+++ b/regress/reg_write_sign_extension.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+"""See https://github.com/unicorn-engine/unicorn/issues/98"""
+
+import unicorn
+ADDR = 0xffaabbcc
+
+def hook_mem_invalid(mu, access, address, size, value, user_data):
+    print ">>> Expected value: 0x%x, actual value: 0x%x" % (ADDR, address)
+    assert(address == ADDR)
+    mu.mem_map(address & 0xfffff000, 4 * 1024)
+    mu.mem_write(address, b'\xcc')
+    return True
+
+mu = unicorn.Uc(unicorn.UC_ARCH_X86, unicorn.UC_MODE_32)
+mu.reg_write(unicorn.x86_const.UC_X86_REG_EBX, ADDR)
+
+mu.mem_map(0x10000000, 1024 * 4)
+# jmp ebx
+mu.mem_write(0x10000000, b'\xff\xe3')
+
+mu.hook_add(unicorn.UC_HOOK_MEM_INVALID, hook_mem_invalid)
+mu.emu_start(0x10000000, 0x10000000 + 2, count=1)