[add] dirty example

example/build.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env sh
+
+CHAIN=$HOME/sat/bin/arm-none-eabi
+PATH=$HOME/sat/arm-none-eabi/bin:$PATH
+
+$CHAIN-gcc \
+    -O2 \
+    -mlittle-endian \
+    -mthumb \
+    -mcpu=cortex-m3 \
+    -ffreestanding \
+    -nostdlib \
+    -nostdinc \
+    main.c
+
+$CHAIN-objcopy \
+    -O binary \
+    a.out \
+    /tmp/foobar

example/main.c

@@ -0,0 +1,27 @@
+typedef unsigned int uint32_t;
+
+#define GPIOC		0x40011000 // port C
+#define GPIOC_CRH	(GPIOC + 0x04) // port configuration register high
+#define GPIOC_ODR	(GPIOC + 0x0c) // port output data register
+#define LED_BLUE	(1<<8) // pin 8
+#define LED_GREEN	(1<<9) // pin 9
+
+#define delay()						\
+do {							\
+  register unsigned int i;				\
+  for (i = 0; i < 1000000; ++i)				\
+    __asm__ __volatile__ ("nop\n\t":::"memory");	\
+} while (0)
+
+static void __attribute__((naked)) __attribute__((used)) main(void)
+{
+  *(volatile uint32_t*)GPIOC_CRH = 0x44444411;
+
+  while (1)
+  {
+    *(volatile uint32_t*)GPIOC_ODR = LED_BLUE | LED_GREEN;
+    delay();
+    *(volatile uint32_t*)GPIOC_ODR = 0;
+    delay();
+  }
+}