On 2/7/25 5:59 AM, Andrew Waterman wrote:
This patch runs counter to the ABI spec, which states that vxrm is not
preserved across calls and is volatile upon function entry [1]. vxrm
does not play the same role as frm plays in the calling convention.
(I won't get into the rationale in this email, but the rationale isn't
especially important: we should follow the ABI.)
[1]
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/3a79e936eec5491078b1133ac943f91ef5fd75fd/riscv-cc.adoc?plain=1#L119-L120
Pan's patch doesn't change the basic property that VXRM has no known
state at function entry or upon return from a function call.
Jeff
