Reverting change to highest virtual address

selfie.c

@@ -1527,7 +1527,8 @@ uint64_t PAGETABLETREE = 1; // two-level page table is default
 uint64_t PHYSICALMEMORYSIZE = 0; // total amount of physical memory available for frames
 uint64_t PHYSICALMEMORYEXCESS = 2; // tolerate more allocation than physically available
 
-uint64_t HIGHESTVIRTUALADDRESS = 4294967295; // VIRTUALMEMORYSIZE * GIGABYTE - 1 (avoiding 32-bit overflow)
+// target-dependent, see init_target()
+uint64_t HIGHESTVIRTUALADDRESS = 4294967288; // VIRTUALMEMORYSIZE * GIGABYTE - WORDSIZE
 
 // host-dependent, see init_memory()
 uint64_t NUMBEROFLEAFPTES = 512; // number of leaf page table entries == PAGESIZE / sizeof(uint64_t*)
@@ -2641,6 +2642,8 @@ void init_target() {
  e_ehsize = 52; // elf header size 52 bytes (ELFCLASS32)
  e_phentsize = 32; // size of program header entry 32 bytes (ELFCLASS32)
  }
+
+ HIGHESTVIRTUALADDRESS = VIRTUALMEMORYSIZE * GIGABYTE - WORDSIZE;
 }
 
 void turn_on_gc_library(uint64_t period, char* name) {
@@ -8530,8 +8533,8 @@ uint64_t virtual_address_of_page(uint64_t page) {
 }
 
 uint64_t is_virtual_address_valid(uint64_t vaddr, uint64_t alignment) {
- // is address in range?
- if (vaddr <= HIGHESTVIRTUALADDRESS)
+ // is address virtual?
+ if (vaddr <= HIGHESTVIRTUALADDRESS + (WORDSIZE - alignment))
  // is address aligned?
  if (vaddr % alignment == 0)
  return 1;