debugging - printing processes on serial

- this patch moves the former printslot() from arch_system.c to
  debug.c and reimplements it slightly. The output is not changed,
  however, the process information is printed in a separate function
  print_proc() in debug.c as such a function is also handy in other
  situations and should be publicly available when debugging.

kernel/debug.c

@@ -161,3 +161,76 @@ schedulerstr(struct proc *scheduler)
 	return "KERNEL";
 }
 
+PUBLIC void print_proc(struct proc *pp)
+{
+	struct proc *depproc = NULL;
+	endpoint_t dep;
+
+	printf("%d: %s %d prio %d time %d/%d cycles 0x%x%08x cr3 0x%lx rts %s misc %s sched %s",
+		proc_nr(pp), pp->p_name, pp->p_endpoint,
+		pp->p_priority, pp->p_user_time,
+		pp->p_sys_time, pp->p_cycles.hi, pp->p_cycles.lo, pp->p_seg.p_cr3,
+		rtsflagstr(pp->p_rts_flags), miscflagstr(pp->p_misc_flags),
+		schedulerstr(pp->p_scheduler));
+
+	dep = P_BLOCKEDON(pp);
+	if(dep != NONE) {
+		printf(" blocked on: ");
+		if(dep == ANY) {
+			printf(" ANY\n");
+		} else {
+			int procno;
+			if(!isokendpt(dep, &procno)) {
+				printf(" ??? %d\n", dep);
+			} else {
+				depproc = proc_addr(procno);
+				if(isemptyp(depproc)) {
+					printf(" empty slot %d???\n", procno);
+					depproc = NULL;
+				} else {
+					printf(" %s\n", depproc->p_name);
+				}
+			}
+		}
+	} else {
+		printf("\n");
+	}
+}
+
+PRIVATE void print_proc_depends(struct proc *pp, const int level)
+{
+	struct proc *depproc = NULL;
+	endpoint_t dep;
+#define COL { int i; for(i = 0; i < level; i++) printf("> "); }
+
+	if(level >= NR_PROCS) {
+		printf("loop??\n");
+		return;
+	}
+
+	COL
+
+	print_proc(pp);
+
+	COL
+	proc_stacktrace(pp);
+
+
+	dep = P_BLOCKEDON(pp);
+	if(dep != NONE) {
+		int procno;
+		if(isokendpt(dep, &procno)) {
+			depproc = proc_addr(procno);
+			if(isemptyp(depproc))
+				depproc = NULL;
+		}
+		if (depproc)
+			print_proc_depends(depproc, level+1);
+	}
+}
+
+PUBLIC void print_proc_recursive(struct proc *pp)
+{
+	print_proc_depends(pp, 0);
+}
+