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Unified Diff: src/x64/lithium-codegen-x64.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/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index c45f91ecac811e288ad0f1b92f71fb6345552faf..c3f3867f67f6b8ed500a2d7dd077a6e4ef39df75 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -3731,66 +3731,6 @@ void LCodeGen::DoPower(LPower* instr) {
}
-void LCodeGen::DoRandom(LRandom* instr) {
- // Assert that register size is twice the size of each seed.
- static const int kSeedSize = sizeof(uint32_t);
- STATIC_ASSERT(kPointerSize == 2 * kSeedSize);
-
- // Load native context
- Register global_object = ToRegister(instr->global_object());
- Register native_context = global_object;
- __ movq(native_context, FieldOperand(
- 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;
- __ movq(state, FieldOperand(native_context, kRandomSeedOffset));
-
- // Load state[0].
- Register state0 = ToRegister(instr->scratch());
- __ movl(state0, FieldOperand(state, ByteArray::kHeaderSize));
- // Load state[1].
- Register state1 = ToRegister(instr->scratch2());
- __ movl(state1, FieldOperand(state, ByteArray::kHeaderSize + kSeedSize));
-
- // state[0] = 18273 * (state[0] & 0xFFFF) + (state[0] >> 16)
- Register scratch3 = ToRegister(instr->scratch3());
- __ movzxwl(scratch3, state0);
- __ imull(scratch3, scratch3, Immediate(18273));
- __ shrl(state0, Immediate(16));
- __ addl(state0, scratch3);
- // Save state[0].
- __ movl(FieldOperand(state, ByteArray::kHeaderSize), state0);
-
- // state[1] = 36969 * (state[1] & 0xFFFF) + (state[1] >> 16)
- __ movzxwl(scratch3, state1);
- __ imull(scratch3, scratch3, Immediate(36969));
- __ shrl(state1, Immediate(16));
- __ addl(state1, scratch3);
- // Save state[1].
- __ movl(FieldOperand(state, ByteArray::kHeaderSize + kSeedSize), state1);
-
- // Random bit pattern = (state[0] << 14) + (state[1] & 0x3FFFF)
- Register random = state0;
- __ shll(random, Immediate(14));
- __ andl(state1, Immediate(0x3FFFF));
- __ addl(random, state1);
-
- // Convert 32 random bits in rax to 0.(32 random bits) in a double
- // by computing:
- // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
- XMMRegister result = ToDoubleRegister(instr->result());
- XMMRegister scratch4 = double_scratch0();
- __ movq(scratch3, V8_INT64_C(0x4130000000000000)); // 1.0 x 2^20 as double
- __ movq(scratch4, scratch3);
- __ movd(result, random);
- __ xorps(result, scratch4);
- __ subsd(result, scratch4);
-}
-
-
void LCodeGen::DoMathExp(LMathExp* instr) {
XMMRegister input = ToDoubleRegister(instr->value());
XMMRegister result = ToDoubleRegister(instr->result());
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