Support mythical ones' complement machines.

diff --git a/Modules/_decimal/libmpdec/mpdecimal.c b/Modules/_decimal/libmpdec/mpdecimal.c
index f0ebca887eaf81d3e309db160b76b22c49d3e2f8..b456db42e21ac43f2afb556e40019172b89a7d94 100644 (file)
--- a/Modules/_decimal/libmpdec/mpdecimal.c
+++ b/Modules/_decimal/libmpdec/mpdecimal.c
@@ -1340,7 +1340,7 @@ mpd_qget_ssize(const mpd_t *a, uint32_t *status)
     if (u <= MPD_SSIZE_MAX) {
         return isneg ? -((mpd_ssize_t)u) : (mpd_ssize_t)u;
     }
-    else if (isneg && u-1 == MPD_SSIZE_MAX) {
+    else if (isneg && u+(MPD_SSIZE_MIN+MPD_SSIZE_MAX) == MPD_SSIZE_MAX) {
         return MPD_SSIZE_MIN;
     }