On Fri, 13 May 2022 at 17:16, Richard Henderson <richard.hender...@linaro.org> wrote: > > On 5/13/22 08:54, Peter Maydell wrote: > >> + s390_vec_write_element64(v1, 0, k << es); > > > > Specifically here, because k is 32 bit but s390_vec_write_element64() > > takes a uint64_t argument, we will do the shift as a signed 32 bit > > value before widening to 64 bits, so if the values of 'k' and 'es' > > are such that we might shift beyond bit 32 we'll get the wrong > > value. It looks like 'es' is one of the MO_* values, so generally > > small, but the upper bound on 'k' is a bit less obvious to me. > > Is the overflow-of-32-bits case impossible? > > No, the upper bound of (k << es) is 16. > > We perform the operation with k in units of element size, so that indexing > works nicely, > then convert back to units of bytes at the end to report results. It's a > byte index into > the vector register, with 16 as an indicator of match not found + eos not > found.
Cool; I've marked the coverity issue as a false positive. thanks -- PMM
