Mismatching Calculations

[M31581]

I have been using the Imperas RISV Tests included with riscvOVPsim for compliance testing and having some queries on the F ISA extension tests.

OVPSim : https://github.com/riscv-ovpsim/imperas-riscv-tests F ISA test download page: https://www.ovpworld.org/library/wikka.php?wakka=riscvOVPsimPlus

These tests from Imperas are the updated RISCV Compliance tests and the fpnew is have some mismatches on the FDIV, FMUL and FSQRT tests.

Here are the mismatching calculations: FPNEW_MISMATCH_COMPLIANCE_V2.xlsx

I have only seen F ISA extension tests pass with the models (e.g. C/BFM), so this suggests there is a mismatch between the RTL and models.

Can you comment on my findings?

[mp-17]

Hello @M31581,

Thanks for reporting. There are some rounding problems with the divider/square root units when used in combination with RNE policy. Indeed, there is a plan to update the entire divsqrt unit. Have you also found mismatches with fmul operations? I don't find them in the .xlsl file.

Best regards, Matteo

[M31581]

Hi @mp-17

Thanks for confirming, good to here there is a plan to update the entire divsqrt unit. Yes I have found mismatches in the fmul operations, the "I-FDIV-S-DYN-RDN-01 and I-FDIV-S-RDN-01" table is actually a typo it is the "I-FMUL-S-DYN-RDN-01 and I-FMUL-S-RDN-01".

I have just updated the table with correct info.

Regards, Tommy