/* * Written by J.T. Conklin <jtc@netbsd.org>. * Adapted for exp2 by Ulrich Drepper <drepper@cygnus.com>. * Public domain. */ #include <machine/asm.h> ENTRY(__ieee754_exp2) fldl 4(%esp) /* I added the following ugly construct because exp(+-Inf) resulted in NaN. The ugliness results from the bright minds at Intel. For the i686 the code can be written better. -- drepper@cygnus.com. */ fxam /* Is NaN or +-Inf? */ fstsw %ax movb $0x45, %dh andb %ah, %dh cmpb $0x05, %dh je 1f /* Is +-Inf, jump. */ fld %st frndint /* int(x) */ fsubr %st,%st(1) /* fract(x) */ fxch f2xm1 /* 2^(fract(x)) - 1 */ fld1 faddp /* 2^(fract(x)) */ fscale /* e^x */ fstp %st(1) ret 1: testl $0x200, %eax /* Test sign. */ jz 2f /* If positive, jump. */ fstp %st fldz /* Set result to 0. */ 2: ret END (__ieee754_exp2) strong_alias (__ieee754_exp2, __exp2_finite)