[Bug math/14471] Inaccurate y0f function on x86_32 and x86_64

["liubov.dmitrieva at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=14471

--- Comment #2 from Liubov Dmitrieva <liubov.dmitrieva at gmail dot com> 2012-08-16 08:16:33 UTC ---
>> represent the test argument using a hex float value
Updated test:


#include <stdio.h>
#include <math.h>
#include <fenv.h>

extern float y0f(float);
extern double y0(double);

int main() {
    float a,r1;
    double r2;

    a=0x1.ab8e1ap3;    //argument

    fesetround(FE_TONEAREST); // FE_TONEAREST, FE_UPWARD, FE_DOWNWARD, and
FE_TOWARDZERO

    r1 = y0f(a);  //actual result
    r2 = y0(a);   //actual result 2

    printf("inputs: a = %.6a\n", a);
    printf("actual    = %.6a\n", r1);
    printf("expected  = %.6a\n", r2);
    printf("error     = %f ulp\n", fabs(r1 - r2) * exp2(23.0-logbf(r1)));
    return 0;
}


Result x86:
inputs: a = 0x1.ab8e1ap+3
actual    = -0x1.0038a2p-22
expected  = -0x1.ffef8fp-23
error     = 8301.219724 ulp

Result x86_64:
inputs: a = 0x1.ab8e1ap+3
actual    = -0x1.0010aap-22
expected  = -0x1.ffef8fp-23
error     = 3185.219724 ulp

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