用MDK调试lpc3250程序简单数组复制遇到的奇怪状况

只看该作者 · 2013-10-8 16:06

本帖最后由 sept80 于 2013-10-8 16:07 编辑

数组定义
UNS_8 s[32] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32};
UNS_8 d[32] = {0};

数组复制程序
void copyArray(UNS_8* pA,UNS_8 * pB, UNS_32 num)
{
      while(num > 0)
      {
               *pB = *pA;
               pB++;
               pA++;
               num--;
}
}

调用
copyArray(s,d,32);

反汇编代码
650: void copyArray(UNS_8* pA,UNS_8 * pB, UNS_32 num)
651: {
0x80004B74  E12FFF1E  BX       R14
652:       while(num > 0)
653:       {
0x80004B78  EA000004  B       0x80004B90
654:                *pB = *pA;
0x80004B7C  E5D03000  LDRB    R3,[R0]
0x80004B80  E5C13000  STRB    R3,[R1]
655:                pB++;
0x80004B84  E2811001  ADD    R1,R1,#0x00000001
656:                pA++;
0x80004B88  E2800001  ADD    R0,R0,#0x00000001
657:                num--;
658: }
0x80004B8C  E2422001  SUB    R2,R2,#0x00000001
0x80004B90  E3520000  CMP    R2,#output(0x00000000)
0x80004B94  1AFFFFF8  BNE    0x80004B7C
659: }

结果
d[32] = {0x01,0x02,0x02,0x04,0x03,0x06,0x04,0x08,0x05,0x0A,0x06,0x0C,0x07,0x0E,0x08,0x10,0x09,0x12,0x0A,0x14,0x0B,0x16,0x0C,0x18,0x0D,0x1A,0x0E,0x1C,0x0F,0x1E,0x10,0x20};