SMOD description

https://www.evm.codes/?fork=cancun#07:

Note the overflow semantic when $−2^{255}$ is negated.

This is a controversial statement for this opcode.
There is no such statement in https://ethereum.github.io/yellowpaper/paper.pdf.

If needed, you may look deeper into implementation details:

• opSdiv: https://github.com/ethereum/go-ethereum/blob/master/core/vm/instructions.go#L53

• Sdiv: https://github.com/holiman/uint256/blob/master/uint256.go#L789

• opSmod: https://github.com/ethereum/go-ethereum/blob/master/core/vm/instructions.go#L65

• Smod: https://github.com/holiman/uint256/blob/master/uint256.go#L662C1-L682C2

The main point is that SDIV comment—
"Note the overflow semantic when $−2^{255}$ is negated."—
refers to an overflow case.
In contrast, SMOD does not overflow because its arithmetic logic disregards the sign of the second operand.

Start with the SMOD description at the linked evm.codes Cancun opcode page and compare its overflow wording with the Yellow Paper. If needed, inspect the linked opSmod and Smod implementations to understand the disputed behavior. Done means resolving whether the statement belongs in the SMOD description and updating the wording accordingly.