michaelkuc6/blog_os
1
0
Fork 0
mirror of https://github.com/phil-opp/blog_os.git synced 2025-12-16 14:27:49 +00:00
Code Issues Projects Releases Wiki Activity

Introduction to Paging: fix typo (a -> an)

Browse Source
This commit is contained in:
Leo Cassarani
2019-07-04 21:38:07 +01:00
committed by GitHub
parent 7aec521fa8
commit 41c9efd734
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
blog/content/second-edition/posts/08-paging-introduction/index.md
View File

@@ -145,7 +145,7 @@ We see that each table index consists of 9 bits, which makes sense because each
[5-level page table]: https://en.wikipedia.org/wiki/Intel_5-level_paging
Even though bits 48 to 64 are discarded, they can't be set to arbitrary values. Instead all bits in this range have to be copies of bit 47 in order to keep addresses unique and allow future extensions like the 5-level page table. This is called _sign-extension_ because it's very similar to the [sign extension in two's complement]. When a address is not correctly sign-extended, the CPU throws an exception.
Even though bits 48 to 64 are discarded, they can't be set to arbitrary values. Instead all bits in this range have to be copies of bit 47 in order to keep addresses unique and allow future extensions like the 5-level page table. This is called _sign-extension_ because it's very similar to the [sign extension in two's complement]. When an address is not correctly sign-extended, the CPU throws an exception.
[sign extension in two's complement]: https://en.wikipedia.org/wiki/Two's_complement#Sign_extension