Because riscv32 run simulator on x86 but riscv64 run on x64. X86 normalize 0x7FF4000000000000 to 0x7FFC000000000000 by default.
在2023年4月10日星期一 UTC+8 16:07:13<[email protected]> 写道： > I am writing a test about the vfmv_vf instruction as follows: > > ~~~~~~~~~ > diff --git a/test/cctest/test-assembler-riscv64.cc > b/test/cctest/test-assembler-riscv64.cc > index b1e018e9a30..29d8d174c80 100644 > --- a/test/cctest/test-assembler-riscv64.cc > +++ b/test/cctest/test-assembler-riscv64.cc > @@ -2817,6 +2817,26 @@ UTEST_RVV_VF_VFMERGE_VF_FORM_WITH_RES(float, > int32_t, 32, > ((mask >> i) & 0x1) ? rs1_fval : > src[i]) > #undef UTEST_RVV_VF_VFMERGE_VF_FORM_WITH_RES > > +TEST(RISCV_UTEST_vfmv_vf_double_nan) { > + if (!CpuFeatures::IsSupported(RISCV_SIMD)) return; > + constexpr uint32_t n = 2; > + CcTest::InitializeVM(); > + > + // int64_t rs1_fval = 0x7ff7654321fedcba; > + int64_t rs1_fval = 0x7FF4000000000000; > + int64_t dst[n] = {0}; > + auto fn = [](MacroAssembler& assm) { > + __ VU.set(t0, VSew::E64, Vlmul::m1); > + __ fld(ft0, a0, 0); > + __ vfmv_vf(v1, ft0); > + __ vs(v1, a1, 0, VSew::E64); > + }; > + GenAndRunTest<int64_t, int64_t>((int64_t)&rs1_fval, (int64_t)dst, fn); > + for (uint32_t i = 0; i < n; i++) { > + CHECK_EQ(rs1_fval, dst[i]); > + } > +} > + > // Tests for vector permutation instructions vector slide instructions > #define UTEST_RVV_VP_VSLIDE_VI_FORM_WITH_RES(instr_name, type, width, > array, \ > expect_res) > \ > (END) > ~~~~~~~~~ > > This test has two phenomena in riscv32 and riscv64, riscv32 will normalize > 0x7FF4000000000000 to 0x7FFC000000000000, while riscv64 will not change it. > > I know that the instruction vfmv_vf should not call the function > get_fpu_register_double in the simulator, but should call the function > get_fpu_register_Float64. > > But I don't quite understand why the function get_fpu_register_double > doesn't normalize nan in riscv64? > > -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-dev/8e443dbc-ead5-41f1-9cc7-b2c2bc4f2671n%40googlegroups.com.
