From 0939363a3ff0a419a44743f6e36360897c4aeaac Mon Sep 17 00:00:00 2001
From: Graham Edgecombe <gpe@grahamedgecombe.com>
Date: Fri, 29 Dec 2017 16:09:41 +0000
Subject: [PATCH] Add rdcycle demo

---
 progmem.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/progmem.c b/progmem.c
index 136a590..d2948bb 100644
--- a/progmem.c
+++ b/progmem.c
@@ -16,11 +16,20 @@ static void uart_puts(const char *str) {
     }
 }
 
+static inline uint32_t rdcycle(void) {
+    uint32_t cycle;
+    __asm__ volatile ("rdcycle %0" : "=r"(cycle));
+    return cycle;
+}
+
 int main() {
     UART_BAUD = FREQ / 9600;
     LEDS = 0xAA;
 
     for (;;) {
         uart_puts("Hello, world!\r\n");
+
+        uint32_t start = rdcycle();
+        while ((rdcycle() - start) <= FREQ);
     }
 }