diff --git a/sys/riscv/riscv/trap.c b/sys/riscv/riscv/trap.c
index 63a46a57331..1f59e4c5371 100644
--- a/sys/riscv/riscv/trap.c
+++ b/sys/riscv/riscv/trap.c
@@ -136,15 +136,15 @@ dump_regs(struct trapframe *frame)
 	int n;
 	int i;
 
-	n = (sizeof(frame->tf_t) / sizeof(frame->tf_t[0]));
+	n = nitems(frame->tf_t);
 	for (i = 0; i < n; i++)
 		printf("t[%d] == 0x%016lx\n", i, frame->tf_t[i]);
 
-	n = (sizeof(frame->tf_s) / sizeof(frame->tf_s[0]));
+	n = nitems(frame->tf_s);
 	for (i = 0; i < n; i++)
 		printf("s[%d] == 0x%016lx\n", i, frame->tf_s[i]);
 
-	n = (sizeof(frame->tf_a) / sizeof(frame->tf_a[0]));
+	n = nitems(frame->tf_a);
 	for (i = 0; i < n; i++)
 		printf("a[%d] == 0x%016lx\n", i, frame->tf_a[i]);