Hi Richard, thank you for taking a look.
On Thu, Oct 4, 2018 at 2:13 PM Richard Henderson <richard.hender...@linaro.org> wrote: > Think first about how, if PC >= LEND or LEND - PC > PAGE_SIZE, that all of the > loop stuff is irrelevant because we won't hit LEND within this TB. > > Think second about how to represent the common case -- how LOOP sets LBEG and > LEND together. That is, LEND - LBEG <= 256. So, usually, we can also have an > exact representation of LBEG and have a direct link rather than an indirect > link. I tried similar thing as a followup to my original patch, recording entire LBEG in the cs_base -- surprisingly to me it made no measurable difference on my tests. > But I presume that one can play games with special registers to create > ranges that LOOP won't. So we need some setting that will indicate that. > > Consider CS_BASE fields: > > [12: 0] EDIF = LEND - PC, if PC < LEND && LEND - PC < 2*PAGE_SIZE, or 0. That has the same issue as my original patch: two TBs with PC > LEND in both may be linked together, and then LEND may change, so that PC1 > LEND and PC2 < LEND. But I guess always storing low 13 bits of LEND - PC should work? I'll play with it... -- Thanks. -- Max
