Change Details

The lr.w instruction used to read the value from memory sign-extends the value read from memory. If the value in memory has the MSB set, then the result of the sign-extension will have the upper 32 bits set the bne comparison will always fail even if the lower 32 bits are identical. To fix, use a pair of shift instructions to clear the upper 32 bits of the value read from memory after the load.

The lr.w instruction used to read the value from memory sign-extends the value read from memory. GCC sign-extends the 32-bit comparison value passed in whereas clang currently does not. As a result, if the value being compared has the MSB set, the comparison fails for matching 32-bit values when compiled with clang. Use a cast to explicitly sign-extend the unsigned comparison value. This works with both GCC and clang. There is commentary in the RISC-V spec that suggests that GCC's approach is more correct, but it is not clear if the commentary in the RISC-V spec is binding. Obtained from: Axiado

The lr.w instruction used to read the value from memory sign-extends the value read from memory. If the value in memory has the MSB set,GCC sign-extends the 32-bit comparison then the result of the sign-extension will have the upper 32 bits setvalue passed in whereas clang currently does not. As a result, if the the bnevalue being comparison will always fail even ifed has the MSB set, the lower 32 bits arecomparison fails for matching identical32-bit values when compiled with clang. To fix, use a pair of shift instructions to clear the upper 32 bits ofUse a cast to explicitly sign-extend the unsigned comparison value. This the value read from memory after the load.works with both GCC and clang. There is commentary in the RISC-V spec that suggests that GCC's approach is more correct, but it is not clear if the commentary in the RISC-V spec is binding. Obtained from: Axiado