USPACE_SVC_STACK_BOTTOM
memset((void *)(uv + USPACE_SVC_STACK_BOTTOM), 0xdd,
(USPACE_SVC_STACK_TOP - USPACE_SVC_STACK_BOTTOM));
ptr = (u_char *)pcb + USPACE_SVC_STACK_BOTTOM;
for (loop = 0; loop < (USPACE_SVC_STACK_TOP - USPACE_SVC_STACK_BOTTOM)