SCB_SIZE
if (vec < SCB_IOVECBASE || vec >= SCB_SIZE ||
for (vec = SCB_SIZE - SCB_VECSIZE;
if (vec < SCB_IOVECBASE || vec >= SCB_SIZE ||
KDASSERT(a1 >= SCB_IOVECBASE && a1 < SCB_SIZE);
struct scbvec scb_iovectab[SCB_VECTOIDX(SCB_SIZE - SCB_IOVECBASE)];
#define SCB_NIOVECS SCB_VECTOIDX(SCB_SIZE - SCB_IOVECBASE)