Add runtime support for the nRF52

src/runtime/runtime_nrf.c

@@ -0,0 +1,41 @@
+
+#include "hal/nrf_uart.h"
+#include "nrf.h"
+#include "runtime.h"
+
+void uart_init(uint32_t pin_tx) {
+	NRF_UART0->ENABLE        = UART_ENABLE_ENABLE_Enabled;
+	NRF_UART0->BAUDRATE      = UART_BAUDRATE_BAUDRATE_Baud115200;
+	NRF_UART0->TASKS_STARTTX = 1;
+	NRF_UART0->PSELTXD       = 6;
+}
+
+void uart_send(uint8_t c) {
+	NRF_UART0->TXD = c;
+	while (NRF_UART0->EVENTS_TXDRDY != 1) {}
+	NRF_UART0->EVENTS_TXDRDY = 0;
+}
+
+void _start() {
+	uart_init(6); // pin_tx = 6, for NRF52840-DK
+	main();
+}
+
+__attribute__((weak))
+void __aeabi_unwind_cpp_pr0() {
+	// dummy, not actually used
+}
+
+__attribute__((weak))
+void __aeabi_memclr(uint8_t *dest, size_t n) {
+	// TODO: link with compiler-rt for a better implementation.
+	// For now, use a simple memory zeroer.
+	for (size_t i = 0; i < n; i++) {
+		dest[i] = 0;
+	}
+}
+
+__attribute__((weak))
+void __aeabi_memclr4(uint8_t *dest, size_t n) {
+	__aeabi_memclr(dest, n);
+}