kmallllllllllllloc

kernel/include/kmalloc.h

@@ -15,6 +15,32 @@ void* kzalloc(size_t size);
 // zeroed-out memory. Returns a pointer to allocated memory or NULL.
 void* kcalloc(size_t count, size_t size);
 
+// 9 bytes in 8 bytes
+#define TAG_SHIFT 56
+#define TAG_MASK ((uintptr_t)0xFF << TAG_SHIFT)
+#define SIGN_BIT ((uintptr_t)1 << 55)
+
+typedef struct {
+	uintptr_t bits;
+} tagged_ptr;
+
+static inline tagged_ptr tp_make(void* p, uint8_t tag) {
+	uintptr_t addr = (uintptr_t)p & ~TAG_MASK;
+	return (tagged_ptr){addr | ((uintptr_t)tag << TAG_SHIFT)};
+}
+
+static inline uint8_t tp_tag(tagged_ptr t) {
+	return (uint8_t)(t.bits >> TAG_SHIFT);
+}
+
+static inline void* tp_ptr(tagged_ptr t) {
+	/* Bits 48..55 were untouched and still equal the canonical sign.
+	   Copy bit 55 into bits 56..63. */
+	uintptr_t addr =
+	    (t.bits & SIGN_BIT) ? (t.bits | TAG_MASK) : (t.bits & ~TAG_MASK);
+	return (void*)addr;
+}
+
 // powers of 2
 #define KMALLOC_MAX_SIZE 17
 #define LOWEST_POWER 3
@@ -28,6 +54,12 @@ struct partialy_freelist {
 	struct partialy_freelist* partialy_freelist_nextnode;
 };
 
+// this is used when object is too small to hold the big one in this case we use
+// first object as pointer storage and dont allocate it
+struct partialy_freelist_short {
+	struct partialy_freelist_short* partialy_freelist_nextnode;
+};
+
 union freelists_list {
 	struct freelist* freelists[KMALLOC_MAX_SIZE];
 	struct {