_REG_SPSR
(ucp)->uc_mcontext.__gregs[_REG_SPSR] = 0;
if ((mcp->__gregs[_REG_SPSR] & ~SPSR_NZCV)
CTASSERT(offsetof(struct reg, r_spsr) == _REG_SPSR * sizeof(__greg_t));
mcp->__gregs[_REG_SPSR] &= ~SPSR_A64_BTYPE;
uc->uc_mcontext.__gregs[_REG_SPSR] = ctx->pstate;
ctx->pstate = uc.uc_mcontext.__gregs[_REG_SPSR];