diff --git a/panda/src/device/winRawInputDevice.cxx b/panda/src/device/winRawInputDevice.cxx
index 8448b58da4..0e1eb937bf 100644
--- a/panda/src/device/winRawInputDevice.cxx
+++ b/panda/src/device/winRawInputDevice.cxx
@@ -702,7 +702,7 @@ process_report(PCHAR ptr, size_t size) {
             // Sign extend.
             int value = data[di].RawValue;
             if (value & idx._sign_bit) {
-              value = -(value & ~idx._sign_bit);
+              value -= (idx._sign_bit << 1);
             }
             axis_changed(idx._axis, value);
           } else {