1 files changed, 58 insertions, 0 deletions
diff --git a/led.c b/led.c
new file mode 100644
index 0000000..b0f9c1c
--- /dev/null
+++ b/led.c
@@ -0,0 +1,58 @@
+#include "config.h"
+#include "led.h"
+
+#include <avr/io.h>
+
+void signal_bit_0() {
+	asm volatile (
+		"sbi %0, %1\n\t"
+		"cbi %0, %1\n\t"
+		"rjmp .+0\n\t"
+		"rjmp .+0\n\t"
+		"rjmp .+0\n\t"
+		"nop\n\t"
+		:
+		: "I" (_SFR_IO_ADDR(PORTB)), "I" (PIN_LED)
+	);
+}
+
+void signal_bit_1() {
+	asm volatile (
+		"sbi %0, %1\n\t"
+		"rjmp .+0\n\t"
+		"nop\n\t"
+		"cbi %0, %1\n\t"
+		"rjmp .+0\n\t"
+		"rjmp .+0\n\t"
+		:
+		: "I" (_SFR_IO_ADDR(PORTB)), "I" (PIN_LED)
+	);
+}
+
+void signal_byte(unsigned char byte) {
+	for (unsigned char mask = 0x80; mask != 0; mask >>= 1) {
+		if (byte & mask)
+			signal_bit_1();
+		else
+			signal_bit_0();
+	}
+}
+
+void signal_led(struct colour *c) {
+	signal_byte(c->r);
+	signal_byte(c->g);
+	signal_byte(c->b);
+}
+
+void signal_led_sequence(int num_leds, struct colour *seq, int num_seq, int width, int start) {
+	for(int i = 0; i < num_leds; ++i) {
+		int j, p = i - start;
+
+		if (p >= 0)
+			j = (p / width % num_seq);
+		else
+			j = (num_seq - ((p + 1) / -width % num_seq) - 1);
+
+		signal_led(&seq[j]);
+	}
+}