On 3/18/19 12:46 PM, Peter Maydell wrote: > Hi; for the M-profile floating point work I'm going to need I think > three new TB flags (to control whether to generate the code to do > the various independent things the pseudocode ExecuteFPCheck() function > does before executing any FP insn). Unfortunately we currently have > only 2 unused bits in the arm TB flags word. > > I can see two possible ways to get the 3rd bit: > (1) overload the meaning of an existing bit which I know isn't > relevant to M-profile (eg the XSCALE_CPAR or VECLEN or VECSTRIDE bits) > (2) start defining new bits in the currently-unused cs_base word
Either works. But I'd probably reuse (or eliminate) XSCALE_CPAR first. Afaik, xscale never had vfp, so CPAR could overlap FPEXC_EL? r~
