diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/RawParseUtils.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/RawParseUtils.java
index 38e0ddefd..598ebaeb9 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/RawParseUtils.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/RawParseUtils.java
@@ -155,6 +155,8 @@ public final class RawParseUtils {
 			return o;
 		}
 		final boolean isneg = value < 0;
+		if (isneg)
+			value = -value;
 		while (value != 0) {
 			b[--o] = base10byte[value % 10];
 			value /= 10;