Re: [PATCH 2/4] target/ppc: added solutions for building with disable-tcg

[Richard Henderson]

On 4/11/21 10:08 PM, David Gibson wrote:
> Not directly related to what you're trying to accomplish here, but the
> whole vscr_sat thing looks really weird.  I have no idea why we're
> splitting out the storage of VSCR[SAT] for the TCG case at all.  If
> you wanted to clean that up as a preliminary, I'd be grateful.

That's about efficiently implementing the vector saturation instructions in 
TCG.  See GEN_VXFORM_SAT in translate/vmx-impl.c.inc.

The SAT bit is represented as a vector that e.g. compares the result of 
addition with the result of saturating addition.  We don't need to resolve that 
to a single bit until the VSCR register is read.


r~