2.6.4.2.1 Syntax

op{type}{cond} Rt, [Rn {, #offset}] ; immediate offset
op{type}{cond} Rt, [Rn, #offset]! ; pre-indexed
op{type}{cond} Rt, [Rn], #offset ; post-indexed
opD{cond} Rt, Rt2, [Rn {, #offset}] ; immediate offset, two words
opD{cond} Rt, Rt2, [Rn, #offset]! ; pre-indexed, two words
opD{cond} Rt, Rt2, [Rn], #offset ; post-indexed, two words

where:

• op is either LDR (load register) or STR (store register)
• type is one of:
  • B: unsigned byte, zero extend to 32 bits on loads.
  • SB: signed byte, sign extend to 32 bits (LDR only).
  • H: unsigned halfword, zero extend to 32 bits on loads.
  • SH: signed halfword, sign extend to 32 bits (LDR only).
  • -: omit, for word.
• cond is an optional condition code; see 2.6.3.7 Conditional Execution.
• Rt is the register to load or store.
• Rn is the register on which the memory address is based.
• offset is an offset from Rn. If offset is omitted, the address is the contents of Rn.
• Rt2 is the additional register to load or store for two-word operations.