From b59a9219ce4468151a21b3267e54af7533c4e9ef Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sun, 14 Oct 2018 05:24:18 +0100
Subject: [PATCH] redirect subtract through rv_sub

---
 riscv/insns/sub.h         | 2 +-
 riscv/insns/subw.h        | 2 +-
 riscv/sv_insn_redirect.cc | 5 +++++
 riscv/sv_insn_redirect.h  | 1 +
 4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/riscv/insns/sub.h b/riscv/insns/sub.h
index 9ed48f7..ac1a2ff 100644
--- a/riscv/insns/sub.h
+++ b/riscv/insns/sub.h
@@ -1 +1 @@
-WRITE_RD(sext_xlen(RS1 - RS2));
+WRITE_RD(sext_xlen(rv_sub(RS1, RS2)));
diff --git a/riscv/insns/subw.h b/riscv/insns/subw.h
index b4168ef..a17092b 100644
--- a/riscv/insns/subw.h
+++ b/riscv/insns/subw.h
@@ -1,3 +1,3 @@
 require_rv64;
-WRITE_RD(sext32(RS1 - RS2));
+WRITE_RD(sext32(rv_sub(RS1, RS2)));
 
diff --git a/riscv/sv_insn_redirect.cc b/riscv/sv_insn_redirect.cc
index 519248e..f883a7b 100644
--- a/riscv/sv_insn_redirect.cc
+++ b/riscv/sv_insn_redirect.cc
@@ -222,3 +222,8 @@ reg_t sv_proc_t::rv_add(reg_t lhs, reg_t rhs)
     return lhs + rhs;
 }
 
+reg_t sv_proc_t::rv_sub(reg_t lhs, reg_t rhs)
+{
+    return lhs - rhs;
+}
+
diff --git a/riscv/sv_insn_redirect.h b/riscv/sv_insn_redirect.h
index aef52ee..05faf61 100644
--- a/riscv/sv_insn_redirect.h
+++ b/riscv/sv_insn_redirect.h
@@ -95,6 +95,7 @@ public:
     reg_t (zext32)(reg_t v);
 
     reg_t rv_add(reg_t lhs, reg_t rhs);
+    reg_t rv_sub(reg_t lhs, reg_t rhs);
 
 #include "sv_insn_decl.h"
 };
-- 
2.30.2