mbv: add async app, sorta works

mbv/apps/async/main.cc

@@ -0,0 +1,141 @@
+#include "async.h"
+#include "buffer.h"
+#include "gpio.h"
+#include "intc.h"
+#include "interrupts.h"
+#include "pol0.h"
+#include "timer.h"
+#include "trace.h"
+#include "uart.h"
+#include "uart_async.h"
+
+namespace {
+
+using async::AwaitableType;
+Timer* timer0;
+
+void Uart0Isr() {
+    ToggleLed(7);
+    HandleUartIsr();
+}
+
+void Timer0Isr() {
+    SetLed(6);
+    __builtin_trap();
+}
+
+void SetupUart() {
+    InitUarts();
+
+    intc::SetIsr(UART0_IRQN, Uart0Isr);
+    intc::SetIrqEnabled(UART0_IRQN, true);
+}
+
+void SetupTimer() {
+    timer0 = Timer::Instance(TIMER0_BASE);
+    timer0->SetupAsWdt(100'000 * 1000);
+    timer0->EnableT1();
+
+    intc::SetIsr(TIMER0_IRQN, Timer0Isr);
+    intc::SetIrqEnabled(TIMER0_IRQN, true);
+}
+
+void SetupInterrupts() {
+    intc::EnableInterrupts();
+    SetExternalInterruptHandler(intc::InterruptHandler);
+    EnableExternalInterrupts();
+    EnableInterrupts(true);
+}
+
+async::task<> echo() {
+    async::task<uint8_t> reader = UartReadLoop();
+    async::gimme<std::span<const std::byte>> feeder;
+    async::task<> writer = UartWriteLoop(feeder);
+    writer.h.resume();  // advance to first yield
+    while (1) {
+        SetLed(1);
+        uint8_t c = co_await reader;
+        ClearLed(1);
+        ToggleLed(2);
+        feeder.feed(std::as_bytes(std::span{&c, 1}));
+    }
+}
+
+}  // namespace
+
+#define XUL_SR_RX_FIFO_FULL 0x02       /* receive FIFO full */
+#define XUL_SR_RX_FIFO_VALID_DATA 0x01 /* data in receive FIFO */
+
+int main() {
+    SetupUart();
+    UartWriteCrash("uart setup done\r\n");
+    SetupTimer();
+    UartWriteCrash("timer setup done\r\n");
+
+    gpio0->data = 0;
+    SetupInterrupts();
+
+    async::schedule(echo().h);
+
+    UartWriteCrash("init done. starting main loop\r\n");
+
+    async::main_loop([]() {
+        static int cnt = 0;
+        timer0->Pet();
+        if ((cnt++ % 100000) == 0) {
+            ToggleLed(0);
+        }
+        return false;
+    });
+    // should never get here
+}
+
+/// stdlib stuff
+
+#include <sys/time.h>
+
+#include <cstdint>
+
+#include "itoa.h"
+#include "lock.h"
+
+#ifndef SBRK_STATS
+#define SBRK_STATS 0
+#endif
+
+extern unsigned char _heap_begin, _heap_end;
+
+extern "C" void* _sbrk(int increment) {
+    static unsigned char* heap = &_heap_begin;
+    unsigned char* prev_heap = heap;
+    if (heap + increment >= &_heap_end) {
+        UartWriteCrash("Heap overflow!\r\n");
+        return reinterpret_cast<void*>(-1);
+    }
+    heap += increment;
+    return prev_heap;
+}
+
+extern "C" int _gettimeofday(struct timeval* tv, void* tzvp) {
+    (void)tzvp;
+    uint32_t ticks = timer0->GetT1Ticks();
+    tv->tv_sec = ticks / 100000000;
+    tv->tv_usec = (ticks % 100000000) / 100;
+
+    return 0;
+}
+
+extern "C" uint8_t __atomic_exchange_1(volatile void* ptr, uint8_t val,
+                                       int memorder) {
+    (void)memorder;
+    auto* dest = reinterpret_cast<volatile uint8_t*>(ptr);
+    bool ret;
+
+    {
+        InterruptLock lock;
+        ret = *dest;
+        *dest = val;
+    }
+
+    return ret;
+}