Merge pull request #156 from struct/tagging_fixes_docs

fix docs

Author: struct

MEMORY_TAGGING.md

@@ -2,6 +2,8 @@
 
 IsoAlloc supports a software only memory tagging model that is very similar to Chromes [MTECheckedPtr](https://docs.google.com/document/d/1ph7iOorkGqTuETFZp-xvHV4L2rYootuz1ThzAAoGe30/edit?usp=sharing). This technique for pointer protection is inspired by ARM's upcoming Memory Tagging Extension (MTE) due in ARM v8.5-A. ARM MTE is a comprehensive hardware based solution for detecting memory safety issues in release builds of software with very little overhead. ARM MTE uses the Top Byte Ignore (TBI) feature to transparently tag pointers with metadata or a 'tag'. With ARM MTE this tag is mostly transparently checked and removed in hardware. The feature implemented here in IsoAlloc is conceptually very similar except that tagging and untagging of pointers happens in software.
 
+You can read more details about this feature [here](https://struct.github.io/pointer_tagging.html).
+
 Note that this feature is experimental, off by default, and the APIs are subject to change!
 
 ## Overview

README.md

@@ -184,6 +184,8 @@ If all else fails please file an issue on the [github project](https://github.co
 
 `void *iso_alloc_untag_ptr(void *p, iso_alloc_zone_handle *zone)` - Untags a pointer from a private zone if `MEMORY_TAGGING` is enabled.
 
+`uint8_t iso_alloc_get_mem_tag(void *p, iso_alloc_zone_handle *zone)` - Retrieves the 1 byte tag for an untagged pointer if `MEMORY_TAGGING` is enabled.
+
 `void iso_alloc_protect_root()` - Temporarily protects the `iso_alloc` root structure by marking it unreadable.
 
 `void iso_alloc_unprotect_root()` - Undoes the operation performed by `iso_alloc_protect_root`.