keil c251 v5.57 uvision5开发工具 -凯发app

unsigned char a, b, c;
unsigned char darr [0x10];
void funca (void) {
  darr[c] = darr[b];
}
void funcb (void) {
  darr[c] = darr[b];
}
void funcc (void) {
  darr[c] = darr[a]   darr[b];
}
void funcd (void) {
  darr[c] = darr[a]   darr[b];
}
void main(void) {
  funca ();
  funcb ();
  while(1);
}
; function funca (begin)           ; function funcb (begin)            ; function funcc (begin)                ; function funcd (begin)          
    r     mov     a,#low darr          r     mov     a,#low darr           r     mov     a,#low darr -----   ----- r     mov     a,#low darr     
    r     add     a,b                  r     add     a,b                   r     add     a,b               |       r     add     a,b             
          mov     r0,a     -----   -----     mov     r0,a                        mov     r0,a              |             mov     r0,a            
          mov     a,@r0          |           mov     a,@r0                       mov     a,@r0             |             mov     a,@r0           
          mov     r7,a           |           mov     r7,a                        mov     r7,a              |             mov     r7,a            
    r     mov     a,#low darr    |     r     mov     a,#low darr           r     mov     a,#low darr -----   ----- r     mov     a,#low darr     
    r     add     a,c            |     r     add     a,c                   r     add     a,a               |       r     add     a,a             
          mov     r0,a           |           mov     r0,a                        mov     r0,a              |             mov     r0,a            
          mov     @r0,ar7  -----   -----     mov     @r0,ar7                     mov     a,@r0             |             mov     a,@r0           
          ret                    |           ret                                 add     a,r7              |             add     a,r7            
                                 o-> common code for funca and funcb             mov     r7,a              |             mov     r7,a            
                                                                           r     mov     a,#low darr       |       r     mov     a,#low darr     
                                                                           r     add     a,c               |       r     add     a,c             
                                                                                 mov     r0,a              |             mov     r0,a            
                                                                                 mov     @r0,ar7           |             mov     @r0,ar7         
                                                                                 ret                       |             ret                     
                                                                                                           o-> common code for funcc and funcd   

in the example above the functions funcc() and funcd() are removed when the removeunused linker directive is specified. now, the first part of the common code block (function ?l?com0001) is no longer necessary. in previous verions this was still part of the image. with the new linker enhancement even this code block is removed.

----- function ?l?com0001 (begin) -----                                                                  
000021 7408              mov      a,#low darr  ---                                                       
000023 2519              add      a,b             |\                                                     
000025 f8                mov      r0,a            | \                                                    
000026 e6                mov      a,@r0           |  o-> common code for funcc and funcd                 
000027 ff                mov      r7,a            |                                                      
000028 7408              mov      a,#low darr  ---                                                       
00002a         ?l?com0002:                                                                               
00002a f8                mov      r0,a         ---                                                       
00002b e6                mov      a,@r0           |\                                                     
00002c ff                mov      r7,a            | \                                                    
00002d 7408              mov      a,#low darr     |  o-> common code for funca and funcb                 
00002f 251a              add      a,c             |                                                      
000031 f8                mov      r0,a            |                                                      
000032 a607              mov      @r0,ar7      ---                                                       
000034 22                ret                                                                             
----- function ?l?com0001 (end) -------