2 files changed, 2 insertions, 1 deletions
diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index ba8472ec1..f2c81db72 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -3355,7 +3355,7 @@ RTLIL::SigSpec RTLIL::SigSpec::extract(int offset, int length) const
 {
 	unpack();
 	cover("kernel.rtlil.sigspec.extract_pos");
-	return std::vector<RTLIL::SigBit>(bits_.begin() + offset, bits_.begin() + offset + length);
+	return std::vector<RTLIL::SigBit>(bits_.begin() + offset, length >= 0 ? bits_.begin() + offset + length : bits_.end() + length + 1);
 }
 
 void RTLIL::SigSpec::append(const RTLIL::SigSpec &signal)
diff --git a/kernel/rtlil.h b/kernel/rtlil.h
index 1cfe71473..633cb51d6 100644
--- a/kernel/rtlil.h
+++ b/kernel/rtlil.h
@@ -834,6 +834,7 @@ public:
 
 	operator std::vector<RTLIL::SigChunk>() const { return chunks(); }
 	operator std::vector<RTLIL::SigBit>() const { return bits(); }
+	RTLIL::SigBit at(int offset, const RTLIL::SigBit &defval) { return offset < width_ ? (*this)[offset] : defval; }
 
 	unsigned int hash() const { if (!hash_) updhash(); return hash_; };