Add disk write support

src/bus.c

@@ -206,7 +206,9 @@ int bus_io_write(void *user, uint32_t value, uint32_t port) {
                     break;
                 };
                 case 0x40: {
-                    // TODO: write specified disk sector from memory
+                    // write specified disk sector from memory
+                    set_disk_sector(id, value);
+                    write_disk_from_memory(id);
                     break;
                 };
                 case 0x50: {

src/disk.c

@@ -52,3 +52,8 @@ size_t read_disk_into_memory(size_t id) {
     if (id > 3) { puts("attempting to access disk with ID > 3\n"); return 0; }
     return fread(&vm.memory_ram[disk_controller.buffer_pointer], 1, 512, disk_controller.disks[id].file);
 }
+
+size_t write_disk_from_memory(size_t id) {
+    if (id > 3) { puts("attempting to access disk with ID > 3\n"); return 0; }
+    return fwrite(&vm.memory_ram[disk_controller.buffer_pointer], 1, 512, disk_controller.disks[id].file);
+}

src/disk.h

@@ -16,3 +16,4 @@ void remove_disk(size_t id);
 uint64_t get_disk_size(size_t id);
 void set_disk_sector(size_t id, uint64_t sector);
 size_t read_disk_into_memory(size_t id);
+size_t write_disk_from_memory(size_t id);