From WikiChip
Top-byte Ignore (TBI) - ARM
< arm(Redirected from arm/top-byte ignore)

v · d · e
ARM ISA
General
Variants
Extensions
Topics
Versions(all)

Top-byte ignore (TBI) is a feature introduced with ARMv8 that provides facilities for memory tagging by ignoring the most significant 8 bits of the virtual address.

Overview[edit]

Although 64-bit ARM registers are 64-bit wide, virtual addresses require that the top 16 bits must either be 0x0000 or 0xFFFF. TBI is a hardware feature, introduced with AArch64, that allows software to use 8 most significant bits of a 64-bit pointer as a tag. This is done by enabling memory tagging support in the Translation Control Register. When enabled, the top eight bits ([63:56]) of the virtual address are ignored.

See also[edit]


Text document with shapes.svg This article is still a stub and needs your attention. You can help improve this article by editing this page and adding the missing information.