From abfbdde177c3a7155070dda1b2cdc8292054cc26 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Wed, 14 Jul 1999 00:54:57 +0000 Subject: Update. --- sysdeps/i386/fpu/e_exp10f.S | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 sysdeps/i386/fpu/e_exp10f.S (limited to 'sysdeps/i386/fpu/e_exp10f.S') diff --git a/sysdeps/i386/fpu/e_exp10f.S b/sysdeps/i386/fpu/e_exp10f.S new file mode 100644 index 0000000000..4791b99afa --- /dev/null +++ b/sysdeps/i386/fpu/e_exp10f.S @@ -0,0 +1,38 @@ +/* + * Written by Ulrich Drepper. + */ + +#include + +/* e^x = 2^(x * log2(10)) */ +ENTRY(__ieee754_exp10f) + flds 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. */ + fldl2t + fmulp /* x * log2(10) */ + fld %st + frndint /* int(x * log2(10)) */ + fsubr %st,%st(1) /* fract(x * log2(10)) */ + fxch + f2xm1 /* 2^(fract(x * log2(10))) - 1 */ + fld1 + faddp /* 2^(fract(x * log2(10))) */ + 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_exp10f) -- cgit 1.4.1