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How can I get an efficient loop?

I have written the following code to perform a copy procedure between RAM and FLASH Memory:

unsigned char i;
i = 0x00;
do{
i --;
*(&FLASHADDRESS + j + i) = DataBuffer[i];
}while(i != 0x00);

Is there any better way to generate efficient(like DJNZ in assembler) code? :)
THS.

Parents

0 Jon Ward over 20 years ago in reply to Dan Henry

The DJNZ instruction is used wherever possible in do...while, while, and for loops. So, there' is no code reorganization that is required.

line level    source

   1          void main (void)
   2          {
   3   1      volatile unsigned char i;
   4   1
   5   1      while (--i != 0x00)
   6   1        {
   7   2        }
   8   1
   9   1      for (i=100; i; --i)
  10   1        {
  11   2        }
  12   1
  13   1      do
  14   1        {
  15   2        }
  16   1      while (--i);
  17   1      }

             ; FUNCTION main (BEGIN)
                                           ; SOURCE LINE # 1
                                           ; SOURCE LINE # 2
0000         ?C0001:
                                           ; SOURCE LINE # 5
0000 D500FD      R     DJNZ    i,?C0001
                                           ; SOURCE LINE # 6
                                           ; SOURCE LINE # 7
0003         ?C0002:
                                           ; SOURCE LINE # 9
0003 750064      R     MOV     i,#064H
0006         ?C0003:
                                           ; SOURCE LINE # 10
                                           ; SOURCE LINE # 11
0006 D500FD      R     DJNZ    i,?C0003
                                           ; SOURCE LINE # 14
                                           ; SOURCE LINE # 15
0009         ?C0006:
                                           ; SOURCE LINE # 16
0009 D500FD      R     DJNZ    i,?C0006
                                           ; SOURCE LINE # 17
000C 22                RET
             ; FUNCTION main (END)

Jon

Reply

0 Jon Ward over 20 years ago in reply to Dan Henry

The DJNZ instruction is used wherever possible in do...while, while, and for loops. So, there' is no code reorganization that is required.

line level    source

   1          void main (void)
   2          {
   3   1      volatile unsigned char i;
   4   1
   5   1      while (--i != 0x00)
   6   1        {
   7   2        }
   8   1
   9   1      for (i=100; i; --i)
  10   1        {
  11   2        }
  12   1
  13   1      do
  14   1        {
  15   2        }
  16   1      while (--i);
  17   1      }

             ; FUNCTION main (BEGIN)
                                           ; SOURCE LINE # 1
                                           ; SOURCE LINE # 2
0000         ?C0001:
                                           ; SOURCE LINE # 5
0000 D500FD      R     DJNZ    i,?C0001
                                           ; SOURCE LINE # 6
                                           ; SOURCE LINE # 7
0003         ?C0002:
                                           ; SOURCE LINE # 9
0003 750064      R     MOV     i,#064H
0006         ?C0003:
                                           ; SOURCE LINE # 10
                                           ; SOURCE LINE # 11
0006 D500FD      R     DJNZ    i,?C0003
                                           ; SOURCE LINE # 14
                                           ; SOURCE LINE # 15
0009         ?C0006:
                                           ; SOURCE LINE # 16
0009 D500FD      R     DJNZ    i,?C0006
                                           ; SOURCE LINE # 17
000C 22                RET
             ; FUNCTION main (END)

Jon

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