Merge pull request #456 from Freax13/enhancement/faster-from_page_table_indices

optimize from_page_table_indices

Author: josephlr

src/structures/paging/page.rs

@@ -182,12 +182,10 @@ impl Page<Size1GiB> {
         p4_index: PageTableIndex,
         p3_index: PageTableIndex,
     ) -> Self {
-        use bit_field::BitField;
-
         let mut addr = 0;
-        addr.set_bits(39..48, u64::from(p4_index));
-        addr.set_bits(30..39, u64::from(p3_index));
-        Page::containing_address(VirtAddr::new(addr))
+        addr |= u64::from(p4_index) << 39;
+        addr |= u64::from(p3_index) << 30;
+        Page::containing_address(VirtAddr::new_truncate(addr))
     }
 }
 
@@ -199,13 +197,11 @@ impl Page<Size2MiB> {
         p3_index: PageTableIndex,
         p2_index: PageTableIndex,
     ) -> Self {
-        use bit_field::BitField;
-
         let mut addr = 0;
-        addr.set_bits(39..48, u64::from(p4_index));
-        addr.set_bits(30..39, u64::from(p3_index));
-        addr.set_bits(21..30, u64::from(p2_index));
-        Page::containing_address(VirtAddr::new(addr))
+        addr |= u64::from(p4_index) << 39;
+        addr |= u64::from(p3_index) << 30;
+        addr |= u64::from(p2_index) << 21;
+        Page::containing_address(VirtAddr::new_truncate(addr))
     }
 }
 
@@ -218,14 +214,12 @@ impl Page<Size4KiB> {
         p2_index: PageTableIndex,
         p1_index: PageTableIndex,
     ) -> Self {
-        use bit_field::BitField;
-
         let mut addr = 0;
-        addr.set_bits(39..48, u64::from(p4_index));
-        addr.set_bits(30..39, u64::from(p3_index));
-        addr.set_bits(21..30, u64::from(p2_index));
-        addr.set_bits(12..21, u64::from(p1_index));
-        Page::containing_address(VirtAddr::new(addr))
+        addr |= u64::from(p4_index) << 39;
+        addr |= u64::from(p3_index) << 30;
+        addr |= u64::from(p2_index) << 21;
+        addr |= u64::from(p1_index) << 12;
+        Page::containing_address(VirtAddr::new_truncate(addr))
     }
 
     /// Returns the level 1 page table index of this page.