mbv: now with functioning timer interrupts!

And a few other nice things.
The bootloader now has an embedded wozmon!
If you know its offset, you can jump to it from the app.

mbv/apps/app.ld

@@ -1,6 +1,6 @@
 MEMORY
 {
-    RAM (rwx) : ORIGIN = 0x00000800, LENGTH = 14336
+    RAM (rwx) : ORIGIN = 0x80000000, LENGTH = 0x10000000
 }
 
 _vector_table = 0x0;
@@ -37,6 +37,6 @@ SECTIONS
 
     _heap_begin = .;
 
-    _initial_stack_pointer = 16384;
-    _heap_end = _initial_stack_pointer - 1024;
+    _initial_stack_pointer = 0x90000000;
+    _heap_end = 0x8f000000; /* leave 1M for the stack */
 }

mbv/apps/fromddr.ld

@@ -1,43 +0,0 @@
-MEMORY
-{
-/*    RAM (rwx) : ORIGIN = 0x00000800, LENGTH = 14336 */
-    RAM (rwx) : ORIGIN = 0x80000000, LENGTH = 0x10000000
-}
-
-_vector_table = 0x0;
-
-SECTIONS
-{
-    .text :
-    {
-        _text_begin = .;
-        KEEP(*(.start))
-
-        *(.text*)
-        _text_end = .;
-
-        *(.rodata*)
-    } > RAM
-
-    .bss (NOLOAD) :
-    {
-        _bss_begin = .;
-        *(.bss*)
-        *(COMMON)
-        _bss_end = .;
-    } > RAM
-
-    .data :
-    {
-        *(.data*)
-
-        __exidx_start = .;
-        *(.exidx*)
-        __exidx_end = .;
-    } > RAM
-
-    _heap_begin = .;
-
-    _initial_stack_pointer = 16384;
-    _heap_end = _initial_stack_pointer - 1024;
-}

mbv/apps/helloworld/helloworld.cc

@@ -1,10 +1,12 @@
 #include <cstdint>
 
+#include "pol0.h"
+
 struct Gpio {
     volatile uint32_t data;
 };
 
-#define gpio0 ((Gpio*)0x40000000)
+#define gpio0 ((Gpio*)GPIO0_BASE)
 
 void sleep(int ms) {
     for (int m = 0; m < ms; m++) {

mbv/apps/timer/timer.cc

@@ -0,0 +1,47 @@
+#include <cstdint>
+
+#include "intc.h"
+#include "interrupts.h"
+#include "pol0.h"
+#include "timer.h"
+
+namespace {
+
+struct Gpio {
+    volatile uint32_t data;
+};
+
+Gpio* leds = reinterpret_cast<Gpio*>(GPIO0_BASE);
+Timer* timer;
+
+}
+
+void Timer0Isr() { 
+    static int counter = 0;
+    leds->data = counter++;
+
+    timer->Pet();
+    timer->ClearInterrupt();
+}
+
+void SetupTimer() {
+    timer = Timer::Instance(TIMER0_BASE);
+    timer->SetupAsWdt(100'000'000);
+    timer->EnableT1();
+
+    SetIsr(TIMER0_IRQN, Timer0Isr);
+    SetIrqEnabled(TIMER0_IRQN, true);
+    EnableInterrupts();
+}
+
+int main() {
+    leds->data = 0xa0;
+
+    SetupTimer();
+    SetExternalInterruptHandler(InterruptHandler);
+    EnableExternalInterrupts();
+
+    leds->data = 0xa1;
+
+    BiosWozmon();
+}

mbv/apps/wozmon/wozmon.cc

@@ -125,7 +125,6 @@ int main() {
     gpio0->data = 1;
     uint32_t cur_addr = 0;
     uint32_t cur_data = 0;
-    bool writing = false;
 
     char inbuf[64] = {};
     char* inptr = inbuf;