1 ;CM3 在一定程度上支持 64 位整数。 2 ;其中 LDRD/STRD 就是为 64 位整数的数据传送而设的，语法 格式为： 3  4     LDRD.W RL, RH, [Rn, #+/-offset] {!} 5     STRD.W RL, RH, [Rn, #+/-offset] {!} 6     LDRD.W RL, RH, [Rn],#+/-offset 7     STRD.W RL, RH, [Rn],#+/-offset 8  9     LDR R2, =0x1000     ;(0x1000)= 0x1234_5678_ABCD_EF00 : 00 EF CD AB 78 56 34 1210     LDRD.W R0, R1,[R2]  ;R0= 0xABCD_EF00, R1=0x1234_567811     STRD.W R1, R0,[R2]  ;(0x1000)=0xABCD_EF00_1234_5678 : 78 56 34 12 00 EF CD AB

Memory : [ RL ] [ RH ]

For example, the following piece of code stores the 64-bit value 0x0123456789ABCDEF to address 0xA0000000:void perip_64bitaccess(void){  unsigned long long value = 0x0123456789ABCDEF;  *((volatile unsigned long long*) (0xA0000000)) = value;}

 

 

__asm void stm_llout(unsigned long long* addr, unsigned long long value){  STM r0, {r2,r3}  BX LR}__asm unsigned long long ldm_llin(unsigned long long* addr){  LDM r0, {r0,r1}  BX LR}unsigned long long perip_64bitaccess(void){  unsigned long long ullvalue = ldm_llin((unsigned long long*)0x40004000);  stm_llout((unsigned long long*)0x40000000, ullvalue);  return ullvalue;}