17.57 LDTRB

Load Register Byte (unprivileged).


LDTRB Wt, [Xn|SP{, #simm}]


Is the 32-bit name of the general-purpose register to be transferred.
Is the 64-bit name of the general-purpose base register or stack pointer.
Is the optional signed immediate byte offset, in the range -256 to 255, defaulting to 0.


Load Register Byte (unprivileged) loads a byte from memory, zero-extends it, and writes the result to a register. The address that is used for the load is calculated from a base register and an immediate offset.

The memory is restricted as if execution is at EL0 when:

  • Executing at EL1.
  • Executing at EL2, in ARMv8.1, with HCR_EL2.{E2H, TGE} set to {1, 1}.

Otherwise, the access permission is for the Exception level at which the instruction is executed. For information about memory accesses, see Load/Store addressing modes in the ARM Architecture Reference Manual ARMv8, for ARMv8-A architecture profile.

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