New RTS

package.yaml

@@ -14,9 +14,9 @@ data-files:
 - builtin/Builtin.vix
 - rts/Sixten.Builtin.c
 - rts/Sixten.Builtin.ll
-- rts/garbage_collector.c
-- rts/garbage_collector.h
 - rts/main.ll
+- rts/memory.c
+- rts/memory.h
 
 ghc-options:
   - -Wall

rts/memory.c

@@ -0,0 +1,47 @@
+#include "memory.h"
+
+#include <stdlib.h>
+
+static const uintptr_t TAG_BITS = 16;
+static const uintptr_t TAG_MASK = ((uintptr_t)1 << TAG_BITS) - 1;
+
+struct header {
+  uint32_t pointers;
+};
+
+uintptr_t sixten_heap_allocate(uint64_t tag, uint32_t pointers, uint32_t non_pointer_bytes) {
+  uintptr_t bytes = (uintptr_t)pointers * sizeof(void*) + (uintptr_t)non_pointer_bytes;
+  uint8_t* pointer = 0;
+
+  if (bytes > 0) {
+    pointer = malloc(sizeof(struct header) + bytes);
+  }
+
+  struct header* header = (struct header*)pointer;
+  header->pointers = pointers;
+
+  pointer += sizeof(struct header);
+
+  return (uintptr_t)pointer << TAG_BITS | (uintptr_t)(tag & TAG_MASK);
+}
+
+struct sixten_reference sixten_heap_payload(uintptr_t heap_object) {
+  uint8_t* pointer = (uint8_t*)((intptr_t)heap_object >> TAG_BITS);
+  if (pointer == 0) {
+    return (struct sixten_reference) {
+      .pointers = 0,
+      .non_pointers = 0,
+    };
+  }
+
+  struct header* header = (struct header*)(pointer - sizeof(struct header));
+
+  return (struct sixten_reference) {
+    .pointers = pointer,
+    .non_pointers = pointer + header->pointers * sizeof(void*),
+  };
+}
+
+uint64_t sixten_heap_tag(uintptr_t heap_object) {
+  return (uint64_t)(heap_object & TAG_MASK);
+}