From a4e32b43eae351f50d534927b97c4c27a7657418 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sun, 1 Nov 2015 12:12:41 +0100
Subject: [PATCH] libmp: optimize case x/0xffffffff in mpdigdiv() (helps arm)

---
 sys/src/libmp/port/mpdigdiv.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/sys/src/libmp/port/mpdigdiv.c b/sys/src/libmp/port/mpdigdiv.c
index 4a73bb3a4..32b166765 100644
--- a/sys/src/libmp/port/mpdigdiv.c
+++ b/sys/src/libmp/port/mpdigdiv.c
@@ -21,6 +21,19 @@ mpdigdiv(mpdigit *dividend, mpdigit divisor, mpdigit *quotient)
 		return;
 	}
 
+	// very common case
+	if(~divisor == 0){
+		lo += hi;
+		if(lo < hi){
+			hi++;
+			lo++;
+		}
+		if(lo+1 == 0)
+			hi++;
+		*quotient = hi;
+		return;
+	}
+
 	// at this point we know that hi < divisor
 	// just shift and subtract till we're done
 	q = 0;