STRB (register) Store register byte (register) This instruction calculates an address from a base register value and an offset register value, and stores a byte from a 32-bit register to the calculated address. For information about addressing modes, see Load/Store addressing modes. The instruction uses an offset addressing mode, that calculates the address used for the memory access from a base register value and an offset register value. The offset can be optionally shifted and extended. If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored. 0 0 1 1 1 0 0 0 0 0 1 1 0 Z N N STRB <Wt>, [<Xn|SP>, (<Wm>|<Xm>), <extend> {<amount>}] 0 1 1 STRB <Wt>, [<Xn|SP>, <Xm>{, LSL <amount>}] if option<1> == '0' then UNDEFINED; // sub-word index constant ExtendType extend_type = DecodeRegExtend(option); constant integer shift = 0; <Wt> Is the 32-bit name of the general-purpose register to be transferred, encoded in the "Rt" field. <Xn|SP> Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field. <Wm> When option<0> is set to 0, is the 32-bit name of the general-purpose index register, encoded in the "Rm" field. <Xm> When option<0> is set to 1, is the 64-bit name of the general-purpose index register, encoded in the "Rm" field. <extend> Is the index extend specifier, option <extend> 010 UXTW 110 SXTW 111 SXTX <amount> Is the index shift amount, it must be #0, encoded in "S" as 0 if omitted, or as 1 if present. constant integer t = UInt(Rt); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant boolean nontemporal = FALSE; constant boolean tagchecked = TRUE; constant bits(64) offset = ExtendReg(m, extend_type, shift, 64); bits(64) address; constant boolean privileged = PSTATE.EL != EL0; constant AccessDescriptor accdesc = CreateAccDescGPR(MemOp_STORE, nontemporal, privileged, tagchecked); if n == 31 then CheckSPAlignment(); address = SP[]; else address = X[n, 64]; address = AddressAdd(address, offset, accdesc); Mem[address, 1, accdesc] = X[t, 8];