CODEWITHSUNDEEP
visual-studiox86inline-assembly
Fan Zhang
Fan Zhang

Reputation: 629

How to port a asm code to VS 2008

The following code should work at Linux. I want port the following code to Visual Studio 2008, but I am not very familiar with asm code. Could you help me? 

#include <stdint.h>
static inline uint32_t log2(const uint32_t x) {
   uint32_t y;
   asm ( "\tbsr %1, %0\n"
     : "=r"(y)
     : "r" (x)
    );
    return y;
}

Upvotes: 1

Views: 328

Answers (1)

user1233508
user1233508

Reputation:

GCC uses the AT&T syntax. MSVC uses Intel syntax. That function would look something like this (compiles with MSVC 2010 /16.00.40219.01, but I see no reason why it would fail on 2008):

static inline uint32_t log2(const uint32_t x) {
  uint32_t y;
  __asm {
    bsr eax, x
    mov y, eax
  }
  return y;
}

Upvotes: 2

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