Отправлено bialix 18 августа 2004 г. 17:44 В ответ на: Да, сорри, но результат тот же, счас подитожу отправлено patton 18 августа 2004 г. 17:16

C51 COMPILER V7.05   PATTON_TEST2                                                          08/18/2004 16:45:45 PAGE 1   

C51 COMPILER V7.05, COMPILATION OF MODULE PATTON_TEST2
OBJECT MODULE PLACED IN patton_test2.OBJ
COMPILER INVOKED BY: d:\Keil\C51\BIN\C51.EXE patton_test2.c BROWSE DEBUG OBJECTEXTEND CODE
stmt level    source
   1          short testb( char* src )
   2          {
   3   1        short result = *(src+1);
   4   1        *(((char*)&result)+1) = *src; 
   5   1        return result;
   6   1      }
   7          short badtestb( char* packet )
   8          {
   9   1        short result = packet[1] | (((signed char)packet[0])<<8);
  10   1        return result;
  11   1      }
  12          void main()
  13          {
  14   1        char buf[ 2 ];
  15   1        short result, badresult;
  16   1        *(short*)buf = 0x1234;
  17   1        while( 1 )
  18   1        {
  19   2          result = testb( buf );
  20   2          badresult = badtestb( buf );
  21   2          if( result != badresult )
  22   2            break;
  23   2        }
  24   1        error:
  25   1        goto error;
  26   1      }
  27          
C51 COMPILER V7.05   PATTON_TEST2                                                          08/18/2004 16:45:45 PAGE 2   
ASSEMBLY LISTING OF GENERATED OBJECT CODE

             ; FUNCTION _testb (BEGIN)
                                           ; SOURCE LINE # 1
;---- Variable 'src' assigned to Register 'R1/R2/R3' ----
                                           ; SOURCE LINE # 2
                                           ; SOURCE LINE # 3
0000 900001            MOV     DPTR,#01H
0003 120000      E     LCALL   ?C?CLDOPTR
0006 FF                MOV     R7,A
0007 33                RLC     A
0008 95E0              SUBB    A,ACC
000A F500        R     MOV     result,A
000C 8F00        R     MOV     result+01H,R7
                                           ; SOURCE LINE # 4
000E 120000      E     LCALL   ?C?CLDPTR
0011 F500        R     MOV     result+01H,A
                                           ; SOURCE LINE # 5
0013 AE00        R     MOV     R6,result
0015 FF                MOV     R7,A
                                           ; SOURCE LINE # 6
0016         ?C0001:
0016 22                RET     
             ; FUNCTION _testb (END)
             ; FUNCTION _badtestb (BEGIN)
                                           ; SOURCE LINE # 7
;---- Variable 'packet' assigned to Register 'R1/R2/R3' ----
                                           ; SOURCE LINE # 8
                                           ; SOURCE LINE # 9
0000 900001            MOV     DPTR,#01H
0003 120000      E     LCALL   ?C?CLDOPTR
0006 FD                MOV     R5,A
0007 33                RLC     A
0008 95E0              SUBB    A,ACC
000A FC                MOV     R4,A
000B 120000      E     LCALL   ?C?CLDPTR
000E FF                MOV     R7,A
000F EF                MOV     A,R7
0010 4C                ORL     A,R4
0011 FE                MOV     R6,A
0012 ED                MOV     A,R5
0013 FF                MOV     R7,A
;---- Variable 'result' assigned to Register 'R6/R7' ----
                                           ; SOURCE LINE # 10
                                           ; SOURCE LINE # 11
0014         ?C0002:
0014 22                RET     
             ; FUNCTION _badtestb (END)
             ; FUNCTION main (BEGIN)
                                           ; SOURCE LINE # 12
                                           ; SOURCE LINE # 13
                                           ; SOURCE LINE # 16
0000 750012      R     MOV     buf,#012H
0003 750034      R     MOV     buf+01H,#034H
0006         ?C0003:
                                           ; SOURCE LINE # 17
                                           ; SOURCE LINE # 18
                                           ; SOURCE LINE # 19
0006 7B00              MOV     R3,#00H
C51 COMPILER V7.05   PATTON_TEST2                                                          08/18/2004 16:45:45 PAGE 3   
0008 7A00        R     MOV     R2,#HIGH buf
000A 7900        R     MOV     R1,#LOW buf
000C 120000      R     LCALL   _testb
000F 8E00        R     MOV     result,R6
0011 8F00        R     MOV     result+01H,R7
                                           ; SOURCE LINE # 20
0013 120000      R     LCALL   _badtestb
;---- Variable 'badresult' assigned to Register 'R6/R7' ----
                                           ; SOURCE LINE # 21
0016 E500        R     MOV     A,result+01H
0018 6F                XRL     A,R7
0019 7003              JNZ     ?C0008
001B E500        R     MOV     A,result
001D 6E                XRL     A,R6
001E         ?C0008:
001E 60E6              JZ      ?C0003
                                           ; SOURCE LINE # 22
                                           ; SOURCE LINE # 23
                                           ; SOURCE LINE # 24
0020         error:
                                           ; SOURCE LINE # 25
0020 80FE              SJMP    error
             ; FUNCTION main (END)
MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =     78    ----
   CONSTANT SIZE    =   ----    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =   ----       6
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----    ----
END OF MODULE INFORMATION.

C51 COMPILATION COMPLETE.  0 WARNING(S),  0 ERROR(S)

как бы разница есть

• Спасибо, со сдвигами всё равно длиннее — patton   (18.08.2004 18:18, пустое)