B2.105 TTBR1_EL1, Translation Table Base Register 1, EL1

The TTBR1_EL1 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 at EL0 and EL1.

Bit field descriptions

TTBR1_EL1 is a 64-bit register.

Figure B2-88 TTBR1_EL1 bit assignments
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ASID, [63:48]

An ASID for the translation table base address. The TCR_EL1.A1 field selects either TTBR0_EL1.ASID or TTBR1_EL1.ASID.

BADDR[47:x], [47:1]

Translation table base address, bits[47:x]. Bits [x-1:0] are res0.

x is based on the value of TCR_EL1.T0SZ, the stage of translation, and the memory translation granule size.

For instructions on how to calculate it, see the Arm® Architecture Reference Manual Armv8, for Armv8-A architecture profile.

The value of x determines the required alignment of the translation table, that must be aligned to 2x bytes.

If bits [x-1:1] are not all zero, this is a misaligned Translation Table Base Address. Its effects are constrained unpredictable, where bits [x-1:1] are treated as if all the bits are zero. The value read back from those bits is the value written.

CnP, [0]

Common not Private. The possible values are:

0CnP is not supported.

CnP is supported.


There are no configuration notes.

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

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