newlib-cygwin/winsup/mingw/mingwex/fesetenv.c

58 lines
1.6 KiB
C

#include <fenv.h>
#include <float.h>
#include "cpu_features.h"
/* 7.6.4.3
The fesetenv function establishes the floating-point environment
represented by the object pointed to by envp. The argument envp
points to an object set by a call to fegetenv or feholdexcept, or
equal the macro FE_DFL_ENV or an implementation-defined environment
macro. Note that fesetenv merely installs the state of the exception
flags represented through its argument, and does not raise these
exceptions.
*/
extern void (*_imp___fpreset)( void ) ;
int fesetenv (const fenv_t * envp)
{
/* Default mxcsr status is to mask all exceptions. All other bits
are zero. */
unsigned int _csr = FE_ALL_EXCEPT << __MXCSR_EXCEPT_MASK_SHIFT /*= 0x1f80 */;
if (envp == FE_PC64_ENV)
/*
* fninit initializes the control register to 0x37f,
* the status register to zero and the tag word to 0FFFFh.
* The other registers are unaffected.
*/
__asm__ ("fninit");
else if (envp == FE_PC53_ENV)
/*
* MS _fpreset() does same *except* it sets control word
* to 0x27f (53-bit precison).
* We force calling _fpreset in msvcrt.dll
*/
(*_imp___fpreset)();
else if (envp == FE_DFL_ENV)
/* Use the choice made at app startup */
_fpreset();
else
{
__asm__ ("fldenv %0;" : : "m" (*envp));
/* Setting the reserved high order bits of MXCSR causes a segfault */
_csr = envp ->__mxcsr & 0xffff;
}
/* Set MXCSR */
if (__HAS_SSE)
__asm__ volatile ("ldmxcsr %0" : : "m" (_csr));
return 0;
}