1 files changed, 32 insertions, 5 deletions

diff --git a/src/timer-ns.cpp b/src/timer-ns.cpp
index de60e230..a940e1f5 100644
--- a/src/timer-ns.cpp
+++ b/src/timer-ns.cpp
@@ -3,11 +3,31 @@
 
 namespace floormat {
 
+namespace {
+
+#if 1
+constexpr auto MAX = (uint64_t)-1, HALF = MAX/2;
+
+static_assert(MAX - (MAX-0) <= 0);
+static_assert(MAX - (MAX-1) <= 1);
+static_assert(MAX - (MAX-2) <= 2);
+
+static_assert(HALF + HALF + 1 == MAX);;
+static_assert(MAX - HALF <= HALF+1);
+
+//static_assert(MAX - (MAX-1) <= 0); // must fail
+//static_assert(MAX - (MAX-2) <= 1); // must fail
+//static_assert(MAX - HALF <= HALF); // must fail
+
+#endif
+
+} // namespace
+
 Ns operator+(const Ns& lhs, const Ns& rhs)
 {
     constexpr auto max = (uint64_t)-1;
     auto a = lhs.stamp, b = rhs.stamp;
-    fm_assert(max - a < b);
+    fm_assert(max - a <= b);
     return Ns{a + b};
 }
 
@@ -18,6 +38,15 @@ Ns operator-(const Ns& lhs, const Ns& rhs)
     return Ns{a - b};
 }
 
+Ns operator*(const Ns& lhs, uint64_t b)
+{
+    auto a = lhs.stamp;
+    auto x = a * b;
+    //fm_assert(!(a != 0 && x / a != b));
+    fm_assert(a == 0 || x / a == b);
+    return Ns{a * b};
+}
+
 uint64_t operator/(const Ns& lhs, const Ns& rhs)
 {
     auto a = lhs.stamp, b = rhs.stamp;
@@ -25,9 +54,9 @@ uint64_t operator/(const Ns& lhs, const Ns& rhs)
     return a / b;
 }
 
-Ns operator%(const Ns& lhs, const Ns& rhs)
+Ns operator%(const Ns& lhs, uint64_t b)
 {
-    auto a = lhs.stamp, b = rhs.stamp;
+    auto a = lhs.stamp;
     fm_assert(b != 0);
     return Ns{a % b};
 }
@@ -47,7 +76,5 @@ std::strong_ordering operator<=>(const Ns& lhs, const Ns& rhs)
 Ns::operator uint64_t() const { return stamp; }
 Ns::operator float() const { return float(stamp); }
 uint64_t Ns::operator*() const { return stamp; }
-Ns::Ns() : stamp{0} {}
-Ns::Ns(uint64_t x) : stamp{x} {}
 
 } // namespace floormat