From 82372d00398ce3712f0c7e9f243f6828041e0859 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@cs.berkeley.edu>
Date: Fri, 2 Oct 2015 11:39:09 -0700
Subject: [PATCH] clean up shift instruction implementation

---
 riscv/insns/slli.h |  3 +--
 riscv/insns/srai.h | 10 ++--------
 riscv/insns/srl.h  |  5 +----
 riscv/insns/srli.h | 10 ++--------
 4 files changed, 6 insertions(+), 22 deletions(-)

diff --git a/riscv/insns/slli.h b/riscv/insns/slli.h
index dfe7168..26782fd 100644
--- a/riscv/insns/slli.h
+++ b/riscv/insns/slli.h
@@ -1,3 +1,2 @@
-if (SHAMT >= xlen)
-  throw trap_illegal_instruction();
+require(SHAMT < xlen);
 WRITE_RD(sext_xlen(RS1 << SHAMT));
diff --git a/riscv/insns/srai.h b/riscv/insns/srai.h
index 69066ef..7ae1d4e 100644
--- a/riscv/insns/srai.h
+++ b/riscv/insns/srai.h
@@ -1,8 +1,2 @@
-if (xlen == 64)
-  WRITE_RD(sreg_t(RS1) >> SHAMT);
-else
-{
-  if(SHAMT & 0x20)
-    throw trap_illegal_instruction();
-  WRITE_RD(sext32(int32_t(RS1) >> SHAMT));
-}
+require(SHAMT < xlen);
+WRITE_RD(sext_xlen(sext_xlen(RS1) >> SHAMT));
diff --git a/riscv/insns/srl.h b/riscv/insns/srl.h
index 0eb948b..0dabe9e 100644
--- a/riscv/insns/srl.h
+++ b/riscv/insns/srl.h
@@ -1,4 +1 @@
-if (xlen == 64)
-  WRITE_RD(RS1 >> (RS2 & 0x3F));
-else
-  WRITE_RD(sext32((uint32_t)RS1 >> (RS2 & 0x1F)));
+WRITE_RD(sext_xlen(zext_xlen(RS1) >> (RS2 & (xlen-1))));
diff --git a/riscv/insns/srli.h b/riscv/insns/srli.h
index 0cdc853..ea0b40d 100644
--- a/riscv/insns/srli.h
+++ b/riscv/insns/srli.h
@@ -1,8 +1,2 @@
-if (xlen == 64)
-  WRITE_RD(RS1 >> SHAMT);
-else
-{
-  if(SHAMT & 0x20)
-    throw trap_illegal_instruction();
-  WRITE_RD(sext32((uint32_t)RS1 >> SHAMT));
-}
+require(SHAMT < xlen);
+WRITE_RD(sext_xlen(zext_xlen(RS1) >> SHAMT));
-- 
2.30.2