/*
 * Written by J.T. Conklin <jtc@NetBSD.org>.
 * Public domain.
 */

#include <machine/asm.h>

#include "abi.h"


RCSID("$NetBSD: e_expf.S,v 1.6 2008/06/24 17:27:56 drochner Exp $")

/* e^x = 2^(x * log2(e)) */
ENTRY(__ieee754_expf)
        XMM_ONE_ARG_FLOAT_PROLOGUE

        /*
         * catch +/-Inf and NaN arguments
         */
        movl    ARG_FLOAT_ONE,%eax
        andl    $0x7fffffff,%eax
        cmpl    $0x7f800000,%eax
        jae     x_Inf_or_NaN

        flds    ARG_FLOAT_ONE
        fldl2e
        fmulp                           /* x * log2(e) */
        fld     %st(0)
        frndint                         /* int(x * log2(e)) */
        fsubr   %st(0),%st(1)           /* fract(x * log2(e)) */
        fxch
        f2xm1                           /* 2^(fract(x * log2(e))) - 1 */
        fld1
        faddp                           /* 2^(fract(x * log2(e))) */
        fscale                          /* e^x */
        fstp    %st(1)
        XMM_FLOAT_EPILOGUE
        ret

x_Inf_or_NaN:
        /*
         * Return 0 if x is -Inf.  Otherwise just return x, although the
         * C version would return (x + x) (Real Indefinite) if x is a NaN.
         */
        movl    ARG_FLOAT_ONE,%eax
        cmpl    $0xff800000,%eax
        jne     x_not_minus_Inf
        fldz
        XMM_FLOAT_EPILOGUE
        ret

x_not_minus_Inf:
        flds    ARG_FLOAT_ONE
        XMM_FLOAT_EPILOGUE
        ret