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Unified Diff: src/arm/lithium-codegen-arm.cc

Issue 68723002: Implement Math.random() purely in JavaScript. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Comments only Created 7 years, 1 month ago
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Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 56717a29e129e19071133d6fecb60db19bfbad56..156ae1840529e8c97cefb0806678dfbaf1727306 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -3953,68 +3953,6 @@ void LCodeGen::DoPower(LPower* instr) {
}
-void LCodeGen::DoRandom(LRandom* instr) {
- // Assert that the register size is indeed the size of each seed.
- static const int kSeedSize = sizeof(uint32_t);
- STATIC_ASSERT(kPointerSize == kSeedSize);
-
- // Load native context
- Register global_object = ToRegister(instr->global_object());
- Register native_context = global_object;
- __ ldr(native_context, FieldMemOperand(
- global_object, GlobalObject::kNativeContextOffset));
-
- // Load state (FixedArray of the native context's random seeds)
- static const int kRandomSeedOffset =
- FixedArray::kHeaderSize + Context::RANDOM_SEED_INDEX * kPointerSize;
- Register state = native_context;
- __ ldr(state, FieldMemOperand(native_context, kRandomSeedOffset));
-
- // Load state[0].
- Register state0 = ToRegister(instr->scratch());
- __ ldr(state0, FieldMemOperand(state, ByteArray::kHeaderSize));
- // Load state[1].
- Register state1 = ToRegister(instr->scratch2());
- __ ldr(state1, FieldMemOperand(state, ByteArray::kHeaderSize + kSeedSize));
-
- // state[0] = 18273 * (state[0] & 0xFFFF) + (state[0] >> 16)
- Register scratch3 = ToRegister(instr->scratch3());
- Register scratch4 = scratch0();
- __ and_(scratch3, state0, Operand(0xFFFF));
- __ mov(scratch4, Operand(18273));
- __ mul(scratch3, scratch3, scratch4);
- __ add(state0, scratch3, Operand(state0, LSR, 16));
- // Save state[0].
- __ str(state0, FieldMemOperand(state, ByteArray::kHeaderSize));
-
- // state[1] = 36969 * (state[1] & 0xFFFF) + (state[1] >> 16)
- __ and_(scratch3, state1, Operand(0xFFFF));
- __ mov(scratch4, Operand(36969));
- __ mul(scratch3, scratch3, scratch4);
- __ add(state1, scratch3, Operand(state1, LSR, 16));
- // Save state[1].
- __ str(state1, FieldMemOperand(state, ByteArray::kHeaderSize + kSeedSize));
-
- // Random bit pattern = (state[0] << 14) + (state[1] & 0x3FFFF)
- Register random = scratch4;
- __ and_(random, state1, Operand(0x3FFFF));
- __ add(random, random, Operand(state0, LSL, 14));
-
- // 0x41300000 is the top half of 1.0 x 2^20 as a double.
- // Create this constant using mov/orr to avoid PC relative load.
- __ mov(scratch3, Operand(0x41000000));
- __ orr(scratch3, scratch3, Operand(0x300000));
- // Move 0x41300000xxxxxxxx (x = random bits) to VFP.
- DwVfpRegister result = ToDoubleRegister(instr->result());
- __ vmov(result, random, scratch3);
- // Move 0x4130000000000000 to VFP.
- __ mov(scratch4, Operand::Zero());
- DwVfpRegister scratch5 = double_scratch0();
- __ vmov(scratch5, scratch4, scratch3);
- __ vsub(result, result, scratch5);
-}
-
-
void LCodeGen::DoMathExp(LMathExp* instr) {
DwVfpRegister input = ToDoubleRegister(instr->value());
DwVfpRegister result = ToDoubleRegister(instr->result());
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