From 09895ebf2d98783e65930a820e9288703bb1a50b Mon Sep 17 00:00:00 2001
From: "Guillaume \"Vermeille\" Sanchez" <guillaumesa@google.com>
Date: Wed, 11 Mar 2015 14:57:40 +0000
Subject: Inline long shift code

Change-Id: I96887c295eb9a23dad4c9cc05d0a0e3ba17f674d
---
 compiler/optimizing/code_generator_arm.cc | 65 ++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 19 deletions(-)

(limited to 'compiler/optimizing')

diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 07cc41a8d5..0403af1eaf 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -2311,12 +2311,9 @@ void LocationsBuilderARM::HandleShift(HBinaryOperation* op) {
       break;
     }
     case Primitive::kPrimLong: {
-      InvokeRuntimeCallingConvention calling_convention;
-      locations->SetInAt(0, Location::RegisterPairLocation(
-          calling_convention.GetRegisterAt(0), calling_convention.GetRegisterAt(1)));
-      locations->SetInAt(1, Location::RegisterLocation(calling_convention.GetRegisterAt(2)));
-      // The runtime helper puts the output in R0,R1.
-      locations->SetOut(Location::RegisterPairLocation(R0, R1));
+      locations->SetInAt(0, Location::RequiresRegister());
+      locations->SetInAt(1, Location::RequiresRegister());
+      locations->SetOut(Location::RequiresRegister());
       break;
     }
     default:
@@ -2364,24 +2361,54 @@ void InstructionCodeGeneratorARM::HandleShift(HBinaryOperation* op) {
       break;
     }
     case Primitive::kPrimLong: {
-      // TODO: Inline the assembly instead of calling the runtime.
-      InvokeRuntimeCallingConvention calling_convention;
-      DCHECK_EQ(calling_convention.GetRegisterAt(0), first.AsRegisterPairLow<Register>());
-      DCHECK_EQ(calling_convention.GetRegisterAt(1), first.AsRegisterPairHigh<Register>());
-      DCHECK_EQ(calling_convention.GetRegisterAt(2), second.AsRegister<Register>());
-      DCHECK_EQ(R0, out.AsRegisterPairLow<Register>());
-      DCHECK_EQ(R1, out.AsRegisterPairHigh<Register>());
+      Register o_h = out.AsRegisterPairHigh<Register>();
+      Register o_l = out.AsRegisterPairLow<Register>();
+
+      Register high = first.AsRegisterPairHigh<Register>();
+      Register low = first.AsRegisterPairLow<Register>();
+
+      Register second_reg = second.AsRegister<Register>();
 
-      int32_t entry_point_offset;
       if (op->IsShl()) {
-        entry_point_offset = QUICK_ENTRY_POINT(pShlLong);
+        // Shift the high part
+        __ and_(second_reg, second_reg, ShifterOperand(63));
+        __ Lsl(high, high, second_reg);
+        // Shift the low part and `or` what overflowed on the high part
+        __ rsb(IP, second_reg, ShifterOperand(32));
+        __ Lsr(IP, low, IP);
+        __ orr(o_h, high, ShifterOperand(IP));
+        // If the shift is > 32 bits, override the high part
+        __ subs(IP, second_reg, ShifterOperand(32));
+        __ it(PL);
+        __ Lsl(o_h, low, IP, false, PL);
+        // Shift the low part
+        __ Lsl(o_l, low, second_reg);
       } else if (op->IsShr()) {
-        entry_point_offset = QUICK_ENTRY_POINT(pShrLong);
+        // Shift the low part
+        __ and_(second_reg, second_reg, ShifterOperand(63));
+        __ Lsr(low, low, second_reg);
+        // Shift the high part and `or` what underflowed on the low part
+        __ rsb(IP, second_reg, ShifterOperand(32));
+        __ Lsl(IP, high, IP);
+        __ orr(o_l, low, ShifterOperand(IP));
+        // If the shift is > 32 bits, override the low part
+        __ subs(IP, second_reg, ShifterOperand(32));
+        __ it(PL);
+        __ Asr(o_l, high, IP, false, PL);
+        // Shift the high part
+        __ Asr(o_h, high, second_reg);
       } else {
-        entry_point_offset = QUICK_ENTRY_POINT(pUshrLong);
+        // same as Shr except we use `Lsr`s and not `Asr`s
+        __ and_(second_reg, second_reg, ShifterOperand(63));
+        __ Lsr(low, low, second_reg);
+        __ rsb(IP, second_reg, ShifterOperand(32));
+        __ Lsl(IP, high, IP);
+        __ orr(o_l, low, ShifterOperand(IP));
+        __ subs(IP, second_reg, ShifterOperand(32));
+        __ it(PL);
+        __ Lsr(o_l, high, IP, false, PL);
+        __ Lsr(o_h, high, second_reg);
       }
-      __ LoadFromOffset(kLoadWord, LR, TR, entry_point_offset);
-      __ blx(LR);
       break;
     }
     default:
-- 
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