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troubleshooting Question

gcc assembly help in converting windows assembly code to linux gcc.

Avatar of SimonHowald
SimonHowald asked on
10 Comments1 Solution1014 ViewsLast Modified:
64-bit counter increment/decrement on 32-bit system.

atomically in_value is incremented and updated value is returned.
Pseudo code...
__int64* increment(__Int64 *in_value)
__int64 *temp = NULL;
__asm  {
               mov edi, in_value
                mov eax, [edi]
                mov edx, [edi+4]
                mov ecx, edx
                mov ebx, eax
                add ebx, 1
                adc ecx, 0
                lock cmpxchg8b [edi]
                jnz retry
                mov eax, temp
                xor edx, edx
                mov [eax+edx*4], ebx
                mov [eax+edx*4+4], ecx
return *temp;
It works great. I want it be converted into gcc assembly.
I unsuccessfully converted it in to gcc assembly. But its wrong, i dont know how to pass in_value  (hi and low) in one ready.
#define low(x)       *(((unsigned int*)&(x))+0)
#define high(x)      *(((unsigned int*)&(x))+1)
asm volatile (  "mov   %0,  %%edi \n"
                "mov   %1,  %%eax  \n"
                "mov   %2,  %%edx \n"
                "1: \n"
                "mov   %%edx,  %%ecx\n"
             "mov   %%eax, %%ebx \n"
              "add   $1, %%ebx \n"
            "adc   $0, %%ecx \n"
            "lock;  cmpxchg8b %0\n"
            "jnz   1b \n"
                "mov   %%edx, %%edx \n"
                "mov   %3, %%ebx \n"     //Error
                "mov   %3, %%ecx \n"     //Error
               : "=m" (*in_value)
   : "m" (low(*in_value)), "m" (high(*in_value)), "m" (*in_value)
               : "memory", "ebx", "ecx", "eax", "edi");
in_value should not re-read for one cycle to preserve the atomicity.
thank you
Avatar of ravenpl
This problem has been solved!
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