B1.86 TTBR1, Translation Table Base Register 1

The TTBR1 holds the base address of translation table 1, and information about the memory it occupies. This is one of the translation tables for the stage 1 translation of memory accesses from modes other than Hyp mode.

Usage constraints

TTBR1 is part of the Virtual memory control registers functional group.

There are two formats for this register. TTBCR.EAE determines which format of the register is used.


TTBR1 (NS) is architecturally mapped to AArch64 register TTBR1_EL1. See B2.103 TTBR1_EL1, Translation Table Base Register 1, EL1.

If EL3 is using AArch64, there is a single instance of this register.


TTBR1 is a 64-bit register that can also be accessed as a 32-bit value. If it is accessed as a 32-bit register, accesses read and write bits [31:0] and do not modify bits [63:32].

TTBCR.EAE determines which TTBR1 format is used:

  • EAE==0:

    32-bit format is used. TTBR1[63:32] are ignored.

  • EAE==1:

    64-bit format is used.

Bit fields and details not provided in this description are architecturally defined. See the Arm® Architecture Reference Manual Armv8, for Armv8-A architecture profile.

This section contains the following subsections:
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