scheduler: continue rework

kernel-src/lib/bitmap.c

@@ -0,0 +1,40 @@
+#include <bitmap.h>
+#include <errno.h>
+#include <kernel/alloc.h>
+#include <util.h>
+#include <logging.h>
+
+int bitmap_init(bitmap_t *bitmap, size_t size) {
+	bitmap->data = alloc(size);
+	bitmap->size = size;
+
+	return bitmap->data ? 0 : ENOMEM;
+}
+
+void bitmap_set(bitmap_t *bitmap, long idx, int v) {
+	__assert(bitmap->size > idx);
+
+	long bit = 1llu << (idx % sizeof(*bitmap->data));
+
+	if (v)
+		bitmap->data[idx / sizeof(*bitmap->data)] |= bit;
+	else
+		bitmap->data[idx / sizeof(*bitmap->data)] &= ~bit;
+}
+
+// TODO fix start offset search
+long bitmap_find_first_set(bitmap_t *bitmap, long start_offset) {
+	size_t loop_size = ROUND_UP(bitmap->size, sizeof(*bitmap->data)) / sizeof(*bitmap->data);
+
+	long offset = -1;
+
+	for (size_t i = start_offset; i < loop_size; ++i) {
+		if (bitmap->data[i] == 0)
+			continue;
+
+		offset = i * sizeof(*bitmap->data) + __builtin_ctz(bitmap->data[i]);
+		break;
+	}
+
+	return offset;
+}