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e_expf.S revision 1.4 
      1 /*
      2  * Written by J.T. Conklin <jtc (at) netbsd.org>.
      3  * Public domain.
      4  */
      5 
      6 #include <machine/asm.h>
      7 
      8 #include "abi.h"
      9 
     10 
     11 RCSID("$NetBSD: e_expf.S,v 1.4 2001/06/19 00:26:30 fvdl Exp $")
     12 
     13 /* e^x = 2^(x * log2(e)) */
     14 ENTRY(__ieee754_expf)
     15 	XMM_ONE_ARG_FLOAT_PROLOGUE
     16 	flds	ARG_FLOAT_ONE
     17 	fldl2e
     18 	fmulp				/* x * log2(e) */
     19 	fld	%st(0)
     20 	frndint				/* int(x * log2(e)) */
     21 	fsubr	%st(0),%st(1)		/* fract(x * log2(e)) */
     22 	fxch
     23 	f2xm1				/* 2^(fract(x * log2(e))) - 1 */
     24 	fld1
     25 	faddp				/* 2^(fract(x * log2(e))) */
     26 	fscale				/* e^x */
     27 	fstp	%st(1)
     28 	XMM_FLOAT_EPILOGUE
     29 	ret
     30