[boost] [Query] __sync_val_compare_and_swap_4

Subject: [boost] [Query] __sync_val_compare_and_swap_4
From: Alapkumar Sinha (Alapkumar.Sinha_at_[hidden])
Date: 2010-07-23 07:43:09

Hi ,

I am trying to use the Boost Interposes, specifically the message queue.

When Im doing cross compiling boost libraries on Cronus mips board, I am getting below error

undefined reference to `__sync_val_compare_and_swap_4'

Upon analysis we found that in boost/interprocess/details/atomic.hpp, was throwing this error.

I found the solution.

I replaced this returned statement ( __sync_val_compare_and_swap_4 ) and included assembly language code in atomic.hpp.

(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp) { /* return __sync_val_compare_and_swap(const_cast<boost::uint32_t *>(mem), cmp, with);*/

   boost::uint32_t result;

  asm volatile(".set\tpush\n\t"

                       ".set\tnoreorder\n\t"

                       ".set\tnomacro\n\t"

                       "1:\n\t"

                        "ll\t%[result],0(%[mem])\n\t"

                       "bne\t%[result],%[with],2f\n\t"

                        "move\t%[result],$0\n\t"        // delay slot

                        "move\t%[result],%[mem]\n\t"

                        "sc\t%[result],0(%[mem])\n\t"

                        "beq\t%[result],$0,1b\n\t"

                        "nop\n\t"                       // delay slot

                        "2:\n\t"

                        ".set\tpop"

           : [result] "=&r" (result)

           : [mem] "r" (mem), [cmp] "r" (cmp), [with] "r"(with)

           : "memory");

return result;

 }

After this I was able to execute the message queue program successfully on the mips platform.

Can someone confirm if this is the right solution?

Regards,

Alap

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