STRB (register)
Store Register Byte (register) 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 memory accesses, 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.
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | Rm | option | S | 1 | 0 | Rn | Rt | ||||||||||||||
size | opc |
if option<1> == '0' then UNDEFINED; // sub-word index ExtendType extend_type = DecodeRegExtend(option);
Assembler Symbols
<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,
encoded in
option:
|
<amount> |
Is the index shift amount, it must be #0, encoded in "S" as 0 if omitted, or as 1 if present. |
Operation
bits(64) offset = ExtendReg(m, extend_type, 0); if HaveMTEExt() then SetTagCheckedInstruction(TRUE); bits(64) address; bits(8) data; if n == 31 then CheckSPAlignment(); address = SP[]; else address = X[n]; address = address + offset; data = X[t]; Mem[address, 1, AccType_NORMAL] = data;
Operational information
If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.