mp: fix mpnot and add mpasr

1 files changed, 14 insertions, 1 deletions

diff --git a/sys/src/libmp/port/mplogic.c b/sys/src/libmp/port/mplogic.c
index 3dd9be2ab..16de7571b 100644
--- a/sys/src/libmp/port/mplogic.c
+++ b/sys/src/libmp/port/mplogic.c
@@ -85,7 +85,8 @@ void
 mpnot(mpint *b, mpint *r)
 {
 	mpadd(b, mpone, r);
-	r->sign ^= -2;
+	if(r->top != 0)
+		r->sign ^= -2;
 }
 
 void
@@ -193,3 +194,15 @@ mpxtend(mpint *b, int n, mpint *r)
 	}
 	mpnorm(r);
 }
+
+void
+mpasr(mpint *b, int n, mpint *r)
+{
+	if(b->sign > 0 || n <= 0){
+		mpright(b, n, r);
+		return;
+	}
+	mpadd(b, mpone, r);
+	mpright(r, n, r);
+	mpsub(r, mpone, r);
+}