From 7172e26cc446556e6b8241549d5d188b5cb0cd37 Mon Sep 17 00:00:00 2001
From: Gabe Black <gblack@eecs.umich.edu>
Date: Wed, 1 Jul 2009 22:16:36 -0700
Subject: ARM: Add a findLsbSet function and use it to implement clz.

---
 src/arch/arm/isa/decoder.isa | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

(limited to 'src/arch/arm/isa/decoder.isa')

diff --git a/src/arch/arm/isa/decoder.isa b/src/arch/arm/isa/decoder.isa
index 9d2c90b4c..8c9f7aa50 100644
--- a/src/arch/arm/isa/decoder.isa
+++ b/src/arch/arm/isa/decoder.isa
@@ -270,18 +270,8 @@ format DataOp {
                 0x1: decode OPCODE {
                     0x9: BranchExchange::bx({{ }});
                     0xb: PredOp::clz({{
-                        if (Rm == 0)
-                            Rd = 32;
-                        else
-                        {
-                            int i;
-                            for (i = 0; i < 32; i++)
-                            {
-                                if (Rm & (1<<(31-i)))
-                                break;
-                            }
-                            Rd = i;
-                        }
+                        unsigned lsb = findLsbSet(Rm);
+                        Rd = (lsb > 31) ? 32 : lsb;
                     }});
                 }
                 0x2: decode OPCODE {
-- 
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