Arm support for DoubleToIStub (truncating).

src/arm/macro-assembler-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 811 matching lines @@
 void MacroAssembler::VmovLow(DwVfpRegister dst, Register src) {
   if (dst.code() < 16) {
     const LowDwVfpRegister loc = LowDwVfpRegister::from_code(dst.code());
     vmov(loc.low(), src);
   } else {
     vmov(dst, VmovIndexLo, src);
   }
 }
 
 
-void MacroAssembler::ConvertNumberToInt32(Register object,
-                                          Register dst,
-                                          Register heap_number_map,
-                                          Register scratch1,
-                                          Register scratch2,
-                                          Register scratch3,
-                                          DwVfpRegister double_scratch1,
-                                          LowDwVfpRegister double_scratch2,
-                                          Label* not_number) {
-  Label done;
-  UntagAndJumpIfSmi(dst, object, &done);
-  JumpIfNotHeapNumber(object, heap_number_map, scratch1, not_number);
-  vldr(double_scratch1, FieldMemOperand(object, HeapNumber::kValueOffset));
-  ECMAToInt32(dst, double_scratch1,
-              scratch1, scratch2, scratch3, double_scratch2);
-
-  bind(&done);
-}
-
-
 void MacroAssembler::LoadNumber(Register object,
                                 LowDwVfpRegister dst,
                                 Register heap_number_map,
                                 Register scratch,
                                 Label* not_number) {
   Label is_smi, done;
 
   UntagAndJumpIfSmi(scratch, object, &is_smi);
   JumpIfNotHeapNumber(object, heap_number_map, scratch, not_number);
 
@@ skipping 1669 matching lines @@
   // If x is a non integer negative number,
   // floor(x) <=> round_to_zero(x) - 1.
   bind(&negative);
   sub(result, result, Operand(1), SetCC);
   // If result is still negative, go to done, result fetched.
   // Else, we had an overflow and we fall through exception.
   b(mi, done);
   bind(&exception);
 }
 
-
-void MacroAssembler::ECMAToInt32(Register result,
-                                 DwVfpRegister double_input,
-                                 Register scratch,
-                                 Register scratch_high,
-                                 Register scratch_low,
-                                 LowDwVfpRegister double_scratch) {
-  ASSERT(!scratch_high.is(result));
-  ASSERT(!scratch_low.is(result));
-  ASSERT(!scratch_low.is(scratch_high));
-  ASSERT(!scratch.is(result) &&
-         !scratch.is(scratch_high) &&
-         !scratch.is(scratch_low));
-  ASSERT(!double_input.is(double_scratch));
-
-  Label out_of_range, only_low, negate, done;
-
+void MacroAssembler::TryInlineTruncateDoubleToI(Register result,
+                                                DwVfpRegister double_input,
+                                                Label* done) {
+  LowDwVfpRegister double_scratch = kScratchDoubleReg;
   vcvt_s32_f64(double_scratch.low(), double_input);
   vmov(result, double_scratch.low());
 
   // If result is not saturated (0x7fffffff or 0x80000000), we are done.
-  sub(scratch, result, Operand(1));
-  cmp(scratch, Operand(0x7ffffffe));
-  b(lt, &done);
+  sub(ip, result, Operand(1));
+  cmp(ip, Operand(0x7ffffffe));
+  b(lt, done);
+}
 
-  vmov(scratch_low, scratch_high, double_input);
-  Ubfx(scratch, scratch_high,
-       HeapNumber::kExponentShift, HeapNumber::kExponentBits);
-  // Load scratch with exponent - 1. This is faster than loading
-  // with exponent because Bias + 1 = 1024 which is an *ARM* immediate value.
-  sub(scratch, scratch, Operand(HeapNumber::kExponentBias + 1));
-  // If exponent is greater than or equal to 84, the 32 less significant
-  // bits are 0s (2^84 = 1, 52 significant bits, 32 uncoded bits),
-  // the result is 0.
-  // Compare exponent with 84 (compare exponent - 1 with 83).
-  cmp(scratch, Operand(83));
-  b(ge, &out_of_range);
 
-  // If we reach this code, 31 <= exponent <= 83.
-  // So, we don't have to handle cases where 0 <= exponent <= 20 for
-  // which we would need to shift right the high part of the mantissa.
-  // Scratch contains exponent - 1.
-  // Load scratch with 52 - exponent (load with 51 - (exponent - 1)).
-  rsb(scratch, scratch, Operand(51), SetCC);
-  b(ls, &only_low);
-  // 21 <= exponent <= 51, shift scratch_low and scratch_high
-  // to generate the result.
-  mov(scratch_low, Operand(scratch_low, LSR, scratch));
-  // Scratch contains: 52 - exponent.
-  // We needs: exponent - 20.
-  // So we use: 32 - scratch = 32 - 52 + exponent = exponent - 20.
-  rsb(scratch, scratch, Operand(32));
-  Ubfx(result, scratch_high,
-       0, HeapNumber::kMantissaBitsInTopWord);
-  // Set the implicit 1 before the mantissa part in scratch_high.
-  orr(result, result, Operand(1 << HeapNumber::kMantissaBitsInTopWord));
-  orr(result, scratch_low, Operand(result, LSL, scratch));
-  b(&negate);
+void MacroAssembler::TruncateDoubleToI(Register result,
+                                       DwVfpRegister double_input) {
+  Label done;
 
-  bind(&out_of_range);
-  mov(result, Operand::Zero());
-  b(&done);
+  TryInlineTruncateDoubleToI(result, double_input, &done);
 
-  bind(&only_low);
-  // 52 <= exponent <= 83, shift only scratch_low.
-  // On entry, scratch contains: 52 - exponent.
-  rsb(scratch, scratch, Operand::Zero());
-  mov(result, Operand(scratch_low, LSL, scratch));
+  // If we fell through then inline version didn't succeed - call stub instead.
+  push(lr);
+  sub(sp, sp, Operand(kDoubleSize));  // Put input on stack.
+  vstr(double_input, MemOperand(sp, 0));
 
-  bind(&negate);
-  // If input was positive, scratch_high ASR 31 equals 0 and
-  // scratch_high LSR 31 equals zero.
-  // New result = (result eor 0) + 0 = result.
-  // If the input was negative, we have to negate the result.
-  // Input_high ASR 31 equals 0xffffffff and scratch_high LSR 31 equals 1.
-  // New result = (result eor 0xffffffff) + 1 = 0 - result.
-  eor(result, result, Operand(scratch_high, ASR, 31));
-  add(result, result, Operand(scratch_high, LSR, 31));
+  DoubleToIStub stub(sp, result, 0, true, true);
+  CallStub(&stub);
+
+  add(sp, sp, Operand(kDoubleSize));
+  pop(lr);
 
   bind(&done);
 }
+
+
+void MacroAssembler::TruncateHeapNumberToI(Register result,
+                                           Register object) {
+  Label done;
+  LowDwVfpRegister double_scratch = kScratchDoubleReg;
+  ASSERT(!result.is(object));
+
+  vldr(double_scratch,
+       MemOperand(object, HeapNumber::kValueOffset - kHeapObjectTag));
+  TryInlineTruncateDoubleToI(result, double_scratch, &done);
+
+  // If we fell through then inline version didn't succeed - call stub instead.
+  push(lr);
+  DoubleToIStub stub(object,
+                     result,
+                     HeapNumber::kValueOffset - kHeapObjectTag,
+                     true,
+                     true);
+  CallStub(&stub);
+  pop(lr);
+
+  bind(&done);
+}
+
+
+void MacroAssembler::TruncateNumberToI(Register object,
+                                       Register result,
+                                       Register heap_number_map,
+                                       Register scratch1,
+                                       Label* not_number) {
+  Label done;
+  ASSERT(!result.is(object));
+
+  UntagAndJumpIfSmi(result, object, &done);
+  JumpIfNotHeapNumber(object, heap_number_map, scratch1, not_number);
+  TruncateHeapNumberToI(result, object);
+
+  bind(&done);
+}
 
 
 void MacroAssembler::GetLeastBitsFromSmi(Register dst,
                                          Register src,
                                          int num_least_bits) {
   if (CpuFeatures::IsSupported(ARMv7) && !predictable_code_size()) {
     ubfx(dst, src, kSmiTagSize, num_least_bits);
   } else {
     SmiUntag(dst, src);
     and_(dst, dst, Operand((1 << num_least_bits) - 1));
@@ skipping 1191 matching lines @@
   ldr(ip, MemOperand(ip));
   cmp(scratch_reg, ip);
   b(gt, &no_memento_available);
   ldr(scratch_reg, MemOperand(scratch_reg, -AllocationMemento::kSize));
   cmp(scratch_reg,
       Operand(Handle<Map>(isolate()->heap()->allocation_memento_map())));
   bind(&no_memento_available);
 }
 
 
+Register GetRegisterThatIsNotOneOf(Register reg1,
+                                   Register reg2,
+                                   Register reg3,
+                                   Register reg4,
+                                   Register reg5,
+                                   Register reg6) {
+  RegList regs = 0;
+  if (reg1.is_valid()) regs |= reg1.bit();
+  if (reg2.is_valid()) regs |= reg2.bit();
+  if (reg3.is_valid()) regs |= reg3.bit();
+  if (reg4.is_valid()) regs |= reg4.bit();
+  if (reg5.is_valid()) regs |= reg5.bit();
+  if (reg6.is_valid()) regs |= reg6.bit();
+
+  for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {
+    Register candidate = Register::FromAllocationIndex(i);
+    if (regs & candidate.bit()) continue;
+    return candidate;
+  }
+  UNREACHABLE();
+  return no_reg;
+}
+
+
 #ifdef DEBUG
 bool AreAliased(Register reg1,
                 Register reg2,
                 Register reg3,
                 Register reg4,
                 Register reg5,
                 Register reg6) {
   int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() +
     reg3.is_valid() + reg4.is_valid() + reg5.is_valid() + reg6.is_valid();
 
@@ skipping 45 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM