diff options
Diffstat (limited to 'deps/v8/src/x64/code-stubs-x64.cc')
| -rw-r--r-- | deps/v8/src/x64/code-stubs-x64.cc | 114 |
1 files changed, 51 insertions, 63 deletions
diff --git a/deps/v8/src/x64/code-stubs-x64.cc b/deps/v8/src/x64/code-stubs-x64.cc index 2ff00f0402..fc98006f78 100644 --- a/deps/v8/src/x64/code-stubs-x64.cc +++ b/deps/v8/src/x64/code-stubs-x64.cc @@ -122,69 +122,57 @@ void MathPowStub::Generate(MacroAssembler* masm) { __ movp(scratch, Immediate(1)); __ Cvtlsi2sd(double_result, scratch); - if (exponent_type() == TAGGED) { - __ JumpIfNotSmi(exponent, &exponent_not_smi, Label::kNear); - __ SmiToInteger32(exponent, exponent); - __ jmp(&int_exponent); - - __ bind(&exponent_not_smi); - __ Movsd(double_exponent, FieldOperand(exponent, HeapNumber::kValueOffset)); - } - - if (exponent_type() != INTEGER) { - Label fast_power, try_arithmetic_simplification; - // Detect integer exponents stored as double. - __ DoubleToI(exponent, double_exponent, double_scratch, - &try_arithmetic_simplification, - &try_arithmetic_simplification); - __ jmp(&int_exponent); - - __ bind(&try_arithmetic_simplification); - __ Cvttsd2si(exponent, double_exponent); - // Skip to runtime if possibly NaN (indicated by the indefinite integer). - __ cmpl(exponent, Immediate(0x1)); - __ j(overflow, &call_runtime); - - // Using FPU instructions to calculate power. - Label fast_power_failed; - __ bind(&fast_power); - __ fnclex(); // Clear flags to catch exceptions later. - // Transfer (B)ase and (E)xponent onto the FPU register stack. - __ subp(rsp, Immediate(kDoubleSize)); - __ Movsd(Operand(rsp, 0), double_exponent); - __ fld_d(Operand(rsp, 0)); // E - __ Movsd(Operand(rsp, 0), double_base); - __ fld_d(Operand(rsp, 0)); // B, E - - // Exponent is in st(1) and base is in st(0) - // B ^ E = (2^(E * log2(B)) - 1) + 1 = (2^X - 1) + 1 for X = E * log2(B) - // FYL2X calculates st(1) * log2(st(0)) - __ fyl2x(); // X - __ fld(0); // X, X - __ frndint(); // rnd(X), X - __ fsub(1); // rnd(X), X-rnd(X) - __ fxch(1); // X - rnd(X), rnd(X) - // F2XM1 calculates 2^st(0) - 1 for -1 < st(0) < 1 - __ f2xm1(); // 2^(X-rnd(X)) - 1, rnd(X) - __ fld1(); // 1, 2^(X-rnd(X)) - 1, rnd(X) - __ faddp(1); // 2^(X-rnd(X)), rnd(X) - // FSCALE calculates st(0) * 2^st(1) - __ fscale(); // 2^X, rnd(X) - __ fstp(1); - // Bail out to runtime in case of exceptions in the status word. - __ fnstsw_ax(); - __ testb(rax, Immediate(0x5F)); // Check for all but precision exception. - __ j(not_zero, &fast_power_failed, Label::kNear); - __ fstp_d(Operand(rsp, 0)); - __ Movsd(double_result, Operand(rsp, 0)); - __ addp(rsp, Immediate(kDoubleSize)); - __ jmp(&done); - - __ bind(&fast_power_failed); - __ fninit(); - __ addp(rsp, Immediate(kDoubleSize)); - __ jmp(&call_runtime); - } + Label fast_power, try_arithmetic_simplification; + // Detect integer exponents stored as double. + __ DoubleToI(exponent, double_exponent, double_scratch, + &try_arithmetic_simplification, &try_arithmetic_simplification); + __ jmp(&int_exponent); + + __ bind(&try_arithmetic_simplification); + __ Cvttsd2si(exponent, double_exponent); + // Skip to runtime if possibly NaN (indicated by the indefinite integer). + __ cmpl(exponent, Immediate(0x1)); + __ j(overflow, &call_runtime); + + // Using FPU instructions to calculate power. + Label fast_power_failed; + __ bind(&fast_power); + __ fnclex(); // Clear flags to catch exceptions later. + // Transfer (B)ase and (E)xponent onto the FPU register stack. + __ subp(rsp, Immediate(kDoubleSize)); + __ Movsd(Operand(rsp, 0), double_exponent); + __ fld_d(Operand(rsp, 0)); // E + __ Movsd(Operand(rsp, 0), double_base); + __ fld_d(Operand(rsp, 0)); // B, E + + // Exponent is in st(1) and base is in st(0) + // B ^ E = (2^(E * log2(B)) - 1) + 1 = (2^X - 1) + 1 for X = E * log2(B) + // FYL2X calculates st(1) * log2(st(0)) + __ fyl2x(); // X + __ fld(0); // X, X + __ frndint(); // rnd(X), X + __ fsub(1); // rnd(X), X-rnd(X) + __ fxch(1); // X - rnd(X), rnd(X) + // F2XM1 calculates 2^st(0) - 1 for -1 < st(0) < 1 + __ f2xm1(); // 2^(X-rnd(X)) - 1, rnd(X) + __ fld1(); // 1, 2^(X-rnd(X)) - 1, rnd(X) + __ faddp(1); // 2^(X-rnd(X)), rnd(X) + // FSCALE calculates st(0) * 2^st(1) + __ fscale(); // 2^X, rnd(X) + __ fstp(1); + // Bail out to runtime in case of exceptions in the status word. + __ fnstsw_ax(); + __ testb(rax, Immediate(0x5F)); // Check for all but precision exception. + __ j(not_zero, &fast_power_failed, Label::kNear); + __ fstp_d(Operand(rsp, 0)); + __ Movsd(double_result, Operand(rsp, 0)); + __ addp(rsp, Immediate(kDoubleSize)); + __ jmp(&done); + + __ bind(&fast_power_failed); + __ fninit(); + __ addp(rsp, Immediate(kDoubleSize)); + __ jmp(&call_runtime); // Calculate power with integer exponent. __ bind(&int_exponent); |