diff --git a/riscv/insns/addu_w.h b/riscv/insns/addu_w.h
index 4c344494..4b4d9c66 100644
--- a/riscv/insns/addu_w.h
+++ b/riscv/insns/addu_w.h
@@ -1,3 +1,3 @@
 require_rv64;
 require_extension('B');
-WRITE_RD(sext_xlen(RS1 + zext32(RS2)));
+WRITE_RD(sext_xlen(zext32(RS1) + RS2));
diff --git a/riscv/insns/subu_w.h b/riscv/insns/subu_w.h
deleted file mode 100644
index 0afeb147..00000000
--- a/riscv/insns/subu_w.h
+++ /dev/null
@@ -1,3 +0,0 @@
-require_rv64;
-require_extension('B');
-WRITE_RD(sext_xlen(RS1 - zext32(RS2)));
diff --git a/riscv/riscv.mk.in b/riscv/riscv.mk.in
index 5dc6c895..9afbc145 100644
--- a/riscv/riscv.mk.in
+++ b/riscv/riscv.mk.in
@@ -434,7 +434,6 @@ riscv_insn_ext_b = \
 	sroi \
 	sroiw \
 	srow \
-	subu_w \
 	subwu \
 	unshfl \
 	unshfli \