U-boot-1.1.6-2008R1到vdsp5(bf561)的移植记录（19）：分号惹祸

 

  

在移植汇编代码时，VDSP中的分号造成了一些小困扰，但是相比之下，C中嵌入汇编引起的问题则要隐蔽得多，如cpu/blackfin/reset.c中的函数：

__attribute__ ((__l1_text__, __noreturn__))

void bfin_reset(void)

{

     while (1) {

         /* No idea why this is needed, but with out this, the ssync()

          * after SWRST = 0x0 will hang indefinitely ...

          */

         __builtin_bfin_ssync();

 

         /* Initiate system software reset of peripherals */

         bfin_write_SWRST(0x7);

         /* Due to the way reset is handled in the hardware, we need

          * to delay for 5 SCLKS. The only reliable way to do this is

          * to calculate the CCLK/SCLK ratio and multiply 5. For now,

          * we'll assume worse case which is a 1:15 ratio.

          */

         asm(

              "LSETUP (.Lreset_nops,.Lreset_nops) LC0 = %0/n"

              ".Lreset_nops: nop;"

              :

              : "a" (15 * 5)

              : "LC0", "LB0", "LT0"

         );

         /* Clear system software reset */

         bfin_write_SWRST(0);

         __builtin_bfin_ssync();

         /* Issue core reset */

         asm("raise 1");

     }

}

这里有两行的嵌入汇编，当在VDSP下编译时，它的提示信息为：

[Error ea5004] "C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/acc0a74df1e000/acc0a74df1e001.s":59 Syntax Error in :

.Lreset_nops: nop;

syntax error is at or near text '.Lreset_nops'.

Attempting error recovery by ignoring text until the ';'

 

[Error ea5004] "C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/acc0a74df1e000/acc0a74df1e001.s":79 Syntax Error in :

.LN7:

syntax error is at or near text '.LN7'.

Attempting error recovery by ignoring text until the ';'

 

 Previous errors prevent assembly

第一个错误提示还好点，第二个提示就让人不知所云了。实际上，这两个错误都是由嵌入汇编中一个小小的分号引起的，修改后的代码如下：

__attribute__ ((__l1_text__, __noreturn__))

void bfin_reset(void)

{

     while (1) {

         /* No idea why this is needed, but with out this, the ssync()

          * after SWRST = 0x0 will hang indefinitely ...

          */

         __builtin_bfin_ssync();

 

         /* Initiate system software reset of peripherals */

         bfin_write_SWRST(0x7);

         /* Due to the way reset is handled in the hardware, we need

          * to delay for 5 SCLKS. The only reliable way to do this is

          * to calculate the CCLK/SCLK ratio and multiply 5. For now,

          * we'll assume worse case which is a 1:15 ratio.

          */

         asm(

              "LSETUP (.Lreset_nops,.Lreset_nops) LC0 = %0;/n"

              ".Lreset_nops: nop;"

              :

              : "a" (15 * 5)

              : "LC0", "LB0", "LT0"

         );

         /* Clear system software reset */

         bfin_write_SWRST(0);

         __builtin_bfin_ssync();

         /* Issue core reset */

         asm("raise 1;");

     }

}