1 files changed, 15 insertions, 0 deletions
diff --git a/src/libstddjb/tain_sub.c b/src/libstddjb/tain_sub.c
new file mode 100644
index 0000000..f7dd4eb
--- /dev/null
+++ b/src/libstddjb/tain_sub.c
@@ -0,0 +1,15 @@
+/* ISC license. */
+
+#include <skalibs/tai.h>
+
+void tain_sub (tain_t *t, tain_t const *u, tain_t const *v)
+{
+  tain_t uu = *u ;
+  tai_sub(&t->sec, &uu.sec, &v->sec) ;
+  t->nano = uu.nano - v->nano ;
+  if (t->nano > uu.nano)
+  {
+    t->nano += 1000000000U ;
+    tai_u64(&t->sec, tai_sec(&t->sec)-1) ;
+  }
+}