ldexp.c File Reference

#include "libm.h"
#include "libm_util.h"
#include "libm_new.h"

Include dependency graph for ldexp.c:

Go to the source code of this file.

Macros
#define	FN_PROTOTYPE_REF   FN_PROTOTYPE
#define	__amd_handle_error   _handle_error
#define	__amd_ldexp   OP_LDEXP

Functions
double FN_PROTOTYPE_REF()	ldexp (double x, int n)

Macro Definition Documentation

__amd_handle_error

#define __amd_handle_error   _handle_error

Definition at line 33 of file ldexp.c.

__amd_ldexp

#define __amd_ldexp   OP_LDEXP

Definition at line 34 of file ldexp.c.

FN_PROTOTYPE_REF

#define FN_PROTOTYPE_REF   FN_PROTOTYPE

Definition at line 32 of file ldexp.c.

Function Documentation

ldexp()

double FN_PROTOTYPE_REF() ldexp	(	double	x,
		int	n
	)

Definition at line 40 of file ldexp.c.

{
    UT64 val,val_x;
    unsigned int sign;
    int exponent;
    val.f64 = x;
    val_x.f64 = x;
    sign = val.u32[1] & 0x80000000;
    val.u32[1] = val.u32[1] & 0x7fffffff; /* remove the sign bit */
 
    if (val.u64 > 0x7ff0000000000000)     /* x is NaN */
        #ifdef WINDOWS
        return __amd_handle_error("ldexp", __amd_ldexp, val_x.u64|0x0008000000000000, _DOMAIN, 0, EDOM, x, n, 2);
        #else
        {
        if(!(val.u64 & 0x0008000000000000))// x is snan
           return __amd_handle_error("ldexp", __amd_ldexp, val_x.u64|0x0008000000000000, _DOMAIN, AMD_F_INVALID, EDOM, x, n, 2);
        else
           return x;
        }
        #endif
 
    if(val.u64 == 0x7ff0000000000000)/* x = +-inf*/
        return x;
 
    if((val.u64 == 0x0000000000000000) || (n==0))
        return x; /* x= +-0 or n= 0*/
 
    exponent = val.u32[1] >> 20; /* get the exponent */
 
    if(exponent == 0)/*x is denormal*/
    {
        val.f64 = val.f64 * VAL_2PMULTIPLIER_DP;/*multiply by 2^53 to bring it to the normal range*/
        exponent = val.u32[1] >> 20; /* get the exponent */
        exponent = exponent + n - MULTIPLIER_DP;
        if(exponent < -MULTIPLIER_DP)/*underflow*/
        {
            val.u32[1] = sign | 0x00000000;
            val.u32[0] = 0x00000000;
            return __amd_handle_error("ldexp", __amd_ldexp, val.u64, _UNDERFLOW, AMD_F_INEXACT|AMD_F_UNDERFLOW, ERANGE, x, (double)n, 2);
        }
        if(exponent > 2046)/*overflow*/
        {
            val.u32[1] = sign | 0x7ff00000;
            val.u32[0] = 0x00000000;
            return __amd_handle_error("ldexp", __amd_ldexp, val.u64, _OVERFLOW, AMD_F_INEXACT|AMD_F_OVERFLOW, ERANGE ,x, (double)n, 2);
        }
 
        exponent += MULTIPLIER_DP;
        val.u32[1] = sign | (exponent << 20) | (val.u32[1] & 0x000fffff);
        val.f64 = val.f64 * VAL_2PMMULTIPLIER_DP;
        return val.f64;
    }
 
    exponent += n;
 
    if(exponent < -MULTIPLIER_DP)/*underflow*/
    {
        val.u32[1] = sign | 0x00000000;
        val.u32[0] = 0x00000000;
        return __amd_handle_error("ldexp", __amd_ldexp, val.u64, _UNDERFLOW, AMD_F_INEXACT|AMD_F_UNDERFLOW, ERANGE, x, (double)n, 2);
    }
 
    if(exponent < 1)/*x is normal but output is debnormal*/
    {
        exponent += MULTIPLIER_DP;
        val.u32[1] = sign | (exponent << 20) | (val.u32[1] & 0x000fffff);
        val.f64 = val.f64 * VAL_2PMMULTIPLIER_DP;
        return val.f64;
    }
 
    if(exponent > 2046)/*overflow*/
    {
        val.u32[1] = sign | 0x7ff00000;
        val.u32[0] = 0x00000000;
    return __amd_handle_error("ldexp", __amd_ldexp, val.u64, _OVERFLOW, AMD_F_INEXACT|AMD_F_OVERFLOW, ERANGE ,x, (double)n, 2);
    }
 
    val.u32[1] = sign | (exponent << 20) | (val.u32[1] & 0x000fffff);
    return val.f64;
}