ARM: Implement memcpy using NEON.

src/arm/codegen-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 94 matching lines @@
   OS::ProtectCode(buffer, actual_size);
 
 #if !defined(USE_SIMULATOR)
   return FUNCTION_CAST<UnaryMathFunction>(buffer);
 #else
   fast_exp_arm_machine_code = buffer;
   return &fast_exp_simulator;
 #endif
 }
 
+#if defined(V8_HOST_ARCH_ARM) && defined (V8_HOST_CAN_READ_UNALIGNED)

[ulan, 2013/06/28 15:07:43]

It looks like V8_HOST_CAN_READ_UNALIGNED (which is set to 1 for armv7) doesn't
imply that the arch supports unaligned fp accesses.

I am getting "bus error" when running this cctest on Android devices:

cctest --nocrankshaft test-utils/MemMove --nobreak-on-abort
--nodead-code-elimination --nofold-constants

+OS::MemCopyUint8Function CreateMemCopyUint8Function(
+      OS::MemCopyUint8Function stub) {
+#if defined(USE_SIMULATOR)
+  return stub;
+#else
+  if (Serializer::enabled()) {
+    return stub;
+  }
+  size_t actual_size;
+  byte* buffer = static_cast<byte*>(OS::Allocate(1 * KB, &actual_size, true));
+  if (buffer == NULL) return stub;
+
+  MacroAssembler masm(NULL, buffer, static_cast<int>(actual_size));
+
+  Register dest = r0;
+  Register src = r1;
+  Register chars = r2;
+  Register temp1 = r3;
+  Label less_4;
+
+  if (CpuFeatures::IsSupported(NEON)) {
+    Label loop, less_256, less_128, less_64, less_32, _16_or_less, _8_or_less;
+    Label size_less_than_8;
+    __ pld(MemOperand(src, 0));
+
+    __ cmp(chars, Operand(8));
+    __ b(lt, &size_less_than_8);
+    __ cmp(chars, Operand(32));
+    __ b(lt, &less_32);
+    if (CpuFeatures::cache_line_size() == 32) {
+      __ pld(MemOperand(src, 32));
+    }
+    __ cmp(chars, Operand(64));
+    __ b(lt, &less_64);
+    __ pld(MemOperand(src, 64));
+    if (CpuFeatures::cache_line_size() == 32) {
+      __ pld(MemOperand(src, 96));
+    }
+    __ cmp(chars, Operand(128));
+    __ b(lt, &less_128);
+    __ pld(MemOperand(src, 128));
+    if (CpuFeatures::cache_line_size() == 32) {
+      __ pld(MemOperand(src, 160));
+    }
+    __ pld(MemOperand(src, 192));
+    if (CpuFeatures::cache_line_size() == 32) {
+      __ pld(MemOperand(src, 224));
+    }
+    __ cmp(chars, Operand(256));
+    __ b(lt, &less_256);
+    __ sub(chars, chars, Operand(256));
+
+    __ bind(&loop);
+    __ pld(MemOperand(src, 256));
+    __ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
+    __ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
+    if (CpuFeatures::cache_line_size() == 32) {
+      __ pld(MemOperand(src, 256));
+    }
+    __ sub(chars, chars, Operand(64), SetCC);
+    __ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
+    __ b(ge, &loop);
+    __ add(chars, chars, Operand(256));
+
+    __ bind(&less_256);
+    __ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
+    __ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
+    __ sub(chars, chars, Operand(128));
+    __ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
+    __ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
+    __ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
+    __ cmp(chars, Operand(64));
+    __ b(lt, &less_64);
+
+    __ bind(&less_128);
+    __ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
+    __ vld1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(src, PostIndex));
+    __ sub(chars, chars, Operand(64));
+    __ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d4, 4), NeonMemOperand(dest, PostIndex));
+
+    __ bind(&less_64);
+    __ cmp(chars, Operand(32));
+    __ b(lt, &less_32);
+    __ vld1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(src, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d0, 4), NeonMemOperand(dest, PostIndex));
+    __ sub(chars, chars, Operand(32));
+
+    __ bind(&less_32);
+    __ cmp(chars, Operand(16));
+    __ b(le, &_16_or_less);
+    __ vld1(Neon8, NeonListOperand(d0, 2), NeonMemOperand(src, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d0, 2), NeonMemOperand(dest, PostIndex));
+    __ sub(chars, chars, Operand(16));
+
+    __ bind(&_16_or_less);
+    __ cmp(chars, Operand(8));
+    __ b(le, &_8_or_less);
+    __ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src, PostIndex));
+    __ vst1(Neon8, NeonListOperand(d0), NeonMemOperand(dest, PostIndex));
+    __ sub(chars, chars, Operand(8));
+
+    // Do a last copy which may overlap with the previous copy (up to 8 bytes).
+    __ bind(&_8_or_less);
+    __ rsb(chars, chars, Operand(8));
+    __ sub(src, src, Operand(chars));
+    __ sub(dest, dest, Operand(chars));
+    __ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src));
+    __ vst1(Neon8, NeonListOperand(d0), NeonMemOperand(dest));
+
+    __ Ret();
+
+    __ bind(&size_less_than_8);
+
+    __ bic(temp1, chars, Operand(0x3), SetCC);
+    __ b(&less_4, eq);
+    __ ldr(temp1, MemOperand(src, 4, PostIndex));
+    __ str(temp1, MemOperand(dest, 4, PostIndex));
+  } else {
+    Register temp2 = ip;
+    Label loop;
+
+    __ bic(temp2, chars, Operand(0x3), SetCC);
+    __ b(&less_4, eq);
+    __ add(temp2, dest, temp2);
+
+    __ bind(&loop);
+    __ ldr(temp1, MemOperand(src, 4, PostIndex));
+    __ str(temp1, MemOperand(dest, 4, PostIndex));
+    __ cmp(dest, temp2);
+    __ b(&loop, ne);
+  }
+
+  __ bind(&less_4);
+  __ mov(chars, Operand(chars, LSL, 31), SetCC);
+  // bit0 => Z (ne), bit1 => C (cs)
+  __ ldrh(temp1, MemOperand(src, 2, PostIndex), cs);
+  __ strh(temp1, MemOperand(dest, 2, PostIndex), cs);
+  __ ldrb(temp1, MemOperand(src), ne);
+  __ strb(temp1, MemOperand(dest), ne);
+  __ Ret();
+
+  CodeDesc desc;
+  masm.GetCode(&desc);
+  ASSERT(!RelocInfo::RequiresRelocation(desc));
+
+  CPU::FlushICache(buffer, actual_size);
+  OS::ProtectCode(buffer, actual_size);
+  return FUNCTION_CAST<OS::MemCopyUint8Function>(buffer);
+#endif
+}
+
+// Convert 8 to 16. The number of character to copy must be at least 8.
+OS::MemCopyUint16Uint8Function CreateMemCopyUint16Uint8Function(
+      OS::MemCopyUint16Uint8Function stub) {
+#if defined(USE_SIMULATOR)
+  return stub;
+#else
+  if (Serializer::enabled()) {
+    return stub;
+  }
+  size_t actual_size;
+  byte* buffer = static_cast<byte*>(OS::Allocate(1 * KB, &actual_size, true));
+  if (buffer == NULL) return stub;
+
+  MacroAssembler masm(NULL, buffer, static_cast<int>(actual_size));
+
+  Register dest = r0;
+  Register src = r1;
+  Register chars = r2;
+  if (CpuFeatures::IsSupported(NEON)) {
+    Register temp = r3;
+    Label loop;
+
+    __ bic(temp, chars, Operand(0x7));
+    __ sub(chars, chars, Operand(temp));
+    __ add(temp, dest, Operand(temp, LSL, 1));
+
+    __ bind(&loop);
+    __ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src, PostIndex));
+    __ vmovl(NeonU8, q0, d0);
+    __ vst1(Neon16, NeonListOperand(d0, 2), NeonMemOperand(dest, PostIndex));
+    __ cmp(dest, temp);
+    __ b(&loop, ne);
+
+    // Do a last copy which will overlap with the previous copy (1 to 8 bytes).
+    __ rsb(chars, chars, Operand(8));
+    __ sub(src, src, Operand(chars));
+    __ sub(dest, dest, Operand(chars, LSL, 1));
+    __ vld1(Neon8, NeonListOperand(d0), NeonMemOperand(src));
+    __ vmovl(NeonU8, q0, d0);
+    __ vst1(Neon16, NeonListOperand(d0, 2), NeonMemOperand(dest));
+    __ Ret();
+  } else {
+    Register temp1 = r3;
+    Register temp2 = ip;
+    Register temp3 = lr;
+    Register temp4 = r4;
+    Label loop;
+    Label not_two;
+
+    __ Push(lr, r4);
+    __ bic(temp2, chars, Operand(0x3));
+    __ add(temp2, dest, Operand(temp2, LSL, 1));
+
+    __ bind(&loop);
+    __ ldr(temp1, MemOperand(src, 4, PostIndex));
+    __ uxtb16(temp3, Operand(temp1, ROR, 0));
+    __ uxtb16(temp4, Operand(temp1, ROR, 8));
+    __ pkhbt(temp1, temp3, Operand(temp4, LSL, 16));
+    __ str(temp1, MemOperand(dest));
+    __ pkhtb(temp1, temp4, Operand(temp3, ASR, 16));
+    __ str(temp1, MemOperand(dest, 4));
+    __ add(dest, dest, Operand(8));
+    __ cmp(dest, temp2);
+    __ b(&loop, ne);
+
+    __ mov(chars, Operand(chars, LSL, 31), SetCC);  // bit0 => ne, bit1 => cs
+    __ b(&not_two, cc);
+    __ ldrh(temp1, MemOperand(src, 2, PostIndex));
+    __ uxtb(temp3, Operand(temp1, ROR, 8));
+    __ mov(temp3, Operand(temp3, LSL, 16));
+    __ uxtab(temp3, temp3, Operand(temp1, ROR, 0));
+    __ str(temp3, MemOperand(dest, 4, PostIndex));
+    __ bind(&not_two);
+    __ ldrb(temp1, MemOperand(src), ne);
+    __ strh(temp1, MemOperand(dest), ne);
+    __ Pop(pc, r4);
+  }
+
+  CodeDesc desc;
+  masm.GetCode(&desc);
+
+  CPU::FlushICache(buffer, actual_size);
+  OS::ProtectCode(buffer, actual_size);
+
+  return FUNCTION_CAST<OS::MemCopyUint16Uint8Function>(buffer);
+#endif
+}
+#endif
 
 #undef __
 
 
 UnaryMathFunction CreateSqrtFunction() {
   return &sqrt;
 }
 
 // -------------------------------------------------------------------------
 // Platform-specific RuntimeCallHelper functions.
@@ skipping 512 matching lines @@
     patcher.masm()->add(r0, pc, Operand(-8));
     patcher.masm()->ldr(pc, MemOperand(pc, -4));
     patcher.masm()->dd(reinterpret_cast<uint32_t>(stub->instruction_start()));
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM