On 01/23/2017 05:50 PM, Kevin Hao wrote: > According to the ISA manual, XSAVES also set the XCOMP_BV[62:0]. My code only > try to be compatible with what the cpu does when excuting XSAVES. The > following > is quoted from 325462-sdm-vol-1-2abcd-3abcd.pdf. > The XSAVES instructions sets bit 63 of the XCOMP_BV field of the XSAVE > header while writing RFBM[62:0] to > XCOMP_BV[62:0]. The XSAVES instruction does not write any part of the XSAVE > header other than the XSTATE_BV > and XCOMP_BV fields.
What purpose does it serve to make copyin_to_xsaves() set that bit, other than helping to hide bugs?
