fixed m,nXq for m > n: this properly throws an error now

1 files changed, 3 insertions, 3 deletions

diff --git a/src/qregisters.cpp b/src/qregisters.cpp
index 615fc77..20f6e99 100644
--- a/src/qregisters.cpp
+++ b/src/qregisters.cpp
@@ -1058,10 +1058,10 @@ StateCopyToQReg::got_register(QRegister &reg)
 		tecoInt to = expressions.pop_num();
 		from = expressions.pop_num();
 
-		if (!Validate::pos(from) || !Validate::pos(to))
-			throw RangeError("X");
-
 		len = to - from;
+
+		if (len < 0 || !Validate::pos(from) || !Validate::pos(to))
+			throw RangeError("X");
 	}
 
 	tr.chrg.cpMin = from;