LDREX 和 STREX 独占加载和存储寄存器。 语法 LDREX{ cond} Rt, [Rn {, #offset}] STREX{ cond} Rd, Rt, [Rn {, #offset}] LDREXB{ cond} Rt, [Rn] 字节加载 STREXB{ cond} Rd, Rt, [Rn] 字节存储 LDREXH{ cond} Rt, [Rn] 半字加载 STREXH{ cond} Rd,