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glibc  2.9
Functions
fesetenv.c File Reference
#include <fenv.h>
#include <assert.h>
#include <bp-sym.h>
#include <shlib-compat.h>

Go to the source code of this file.

Functions

int __fesetenv (const fenv_t *envp)

Function Documentation

int __fesetenv ( const fenv_t envp)

Definition at line 27 of file fesetenv.c.

{
  fenv_t temp;

  /* The memory block used by fstenv/fldenv has a size of 28 bytes.  */
  assert (sizeof (fenv_t) == 28);

  /* Install the environment specified by ENVP.  But there are a few
     values which we do not want to come from the saved environment.
     Therefore, we get the current environment and replace the values
     we want to use from the environment specified by the parameter.  */
  __asm__ ("fnstenv %0" : "=m" (*&temp));

  if (envp == FE_DFL_ENV)
    {
      temp.__control_word |= FE_ALL_EXCEPT;
      temp.__control_word &= ~FE_TOWARDZERO;
      temp.__status_word &= ~FE_ALL_EXCEPT;
      temp.__eip = 0;
      temp.__cs_selector = 0;
      temp.__opcode = 0;
      temp.__data_offset = 0;
      temp.__data_selector = 0;
    }
  else if (envp == FE_NOMASK_ENV)
    {
      temp.__control_word &= ~(FE_ALL_EXCEPT | FE_TOWARDZERO);
      temp.__status_word &= ~FE_ALL_EXCEPT;
      temp.__eip = 0;
      temp.__cs_selector = 0;
      temp.__opcode = 0;
      temp.__data_offset = 0;
      temp.__data_selector = 0;
    }
  else
    {
      temp.__control_word &= ~(FE_ALL_EXCEPT | FE_TOWARDZERO);
      temp.__control_word |= (envp->__control_word
                           & (FE_ALL_EXCEPT | FE_TOWARDZERO));
      temp.__status_word &= ~FE_ALL_EXCEPT;
      temp.__status_word |= envp->__status_word & FE_ALL_EXCEPT;
      temp.__eip = envp->__eip;
      temp.__cs_selector = envp->__cs_selector;
      temp.__opcode = envp->__opcode;
      temp.__data_offset = envp->__data_offset;
      temp.__data_selector = envp->__data_selector;
    }

  __asm__ ("fldenv %0" : : "m" (temp));

  /* Success.  */
  return 0;
}

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