1.1 --- a/src/cpu/x86/vm/assembler_x86.cpp Mon Jun 11 22:38:28 2012 -0700
1.2 +++ b/src/cpu/x86/vm/assembler_x86.cpp Tue Jun 12 10:02:36 2012 +0200
1.3 @@ -6927,21 +6927,42 @@
1.4 addptr(rsp,sizeof(jdouble));
1.5 }
1.6
1.7 +void MacroAssembler::increase_precision() {
1.8 + subptr(rsp, BytesPerWord);
1.9 + fnstcw(Address(rsp, 0));
1.10 + movl(rax, Address(rsp, 0));
1.11 + orl(rax, 0x300);
1.12 + push(rax);
1.13 + fldcw(Address(rsp, 0));
1.14 + pop(rax);
1.15 +}
1.16 +
1.17 +void MacroAssembler::restore_precision() {
1.18 + fldcw(Address(rsp, 0));
1.19 + addptr(rsp, BytesPerWord);
1.20 +}
1.21 +
1.22 void MacroAssembler::fast_pow() {
1.23 // computes X^Y = 2^(Y * log2(X))
1.24 // if fast computation is not possible, result is NaN. Requires
1.25 // fallback from user of this macro.
1.26 + // increase precision for intermediate steps of the computation
1.27 + increase_precision();
1.28 fyl2x(); // Stack: (Y*log2(X)) ...
1.29 pow_exp_core_encoding(); // Stack: exp(X) ...
1.30 + restore_precision();
1.31 }
1.32
1.33 void MacroAssembler::fast_exp() {
1.34 // computes exp(X) = 2^(X * log2(e))
1.35 // if fast computation is not possible, result is NaN. Requires
1.36 // fallback from user of this macro.
1.37 + // increase precision for intermediate steps of the computation
1.38 + increase_precision();
1.39 fldl2e(); // Stack: log2(e) X ...
1.40 fmulp(1); // Stack: (X*log2(e)) ...
1.41 pow_exp_core_encoding(); // Stack: exp(X) ...
1.42 + restore_precision();
1.43 }
1.44
1.45 void MacroAssembler::pow_or_exp(bool is_exp, int num_fpu_regs_in_use) {
