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m68k: avoid undue overflow in cexp

This commit is contained in:
Andreas Schwab 2012-03-23 16:33:37 +01:00
parent 3278063a82
commit 2f6ba7629b
2 changed files with 33 additions and 10 deletions
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2
ChangeLog.m68k
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@ -1,5 +1,7 @@
2012-03-23 Andreas Schwab <schwab@linux-m68k.org> 2012-03-23 Andreas Schwab <schwab@linux-m68k.org>
* sysdeps/m68k/m680x0/fpu/s_cexp.c: Avoid undue overflow.
* sysdeps/m68k/m680x0/fpu/bits/mathinline.h (__inline_mathop1): * sysdeps/m68k/m680x0/fpu/bits/mathinline.h (__inline_mathop1):
Mark asm as volatile. Mark asm as volatile.
(__scalbn): Likewise. (__scalbn): Likewise.

41
sysdeps/m68k/m680x0/fpu/s_cexp.c
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@ -17,6 +17,7 @@
License along with the GNU C Library. If not, see License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */ <http://www.gnu.org/licenses/>. */
#include <float.h>
#include <complex.h> #include <complex.h>
#include <math.h> #include <math.h>
#include "mathimpl.h" #include "mathimpl.h"
@ -43,26 +44,46 @@ s(__cexp) (__complex__ float_type x)
if ((ix_cond & (__M81_COND_NAN|__M81_COND_INF)) == 0) if ((ix_cond & (__M81_COND_NAN|__M81_COND_INF)) == 0)
{ {
/* Imaginary part is finite. */ /* Imaginary part is finite. */
float_type exp_val = m81(__ieee754_exp) (__real__ x); unsigned long rx_cond = __m81_test (__real__ x);
__real__ retval = __imag__ retval = exp_val; if ((rx_cond & (__M81_COND_NAN|__M81_COND_INF)) == 0)
if (m81(__finite) (exp_val))
{ {
float_type sin_ix, cos_ix; const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l);
__asm ("fsincos%.x %2,%1:%0" : "=f" (sin_ix), "=f" (cos_ix) long double sin_ix, cos_ix, exp_val;
: "f" (__imag__ x));
__real__ retval *= cos_ix; __m81_u (__sincosl) (__imag__ x, &sin_ix, &cos_ix);
if (__real__ x > t)
{
long double exp_t = __m81_u(__ieee754_expl) (t);
__real__ x -= t;
sin_ix *= exp_t;
cos_ix *= exp_t;
if (__real__ x > t)
{
__real__ x -= t;
sin_ix *= exp_t;
cos_ix *= exp_t;
}
}
exp_val = __m81_u(__ieee754_expl) (__real__ x);
__real__ retval = exp_val * cos_ix;
if (ix_cond & __M81_COND_ZERO) if (ix_cond & __M81_COND_ZERO)
__imag__ retval = __imag__ x; __imag__ retval = __imag__ x;
else else
__imag__ retval *= sin_ix; __imag__ retval = exp_val * sin_ix;
} }
else else
{ {
/* Compute the sign of the result. */ /* Compute the sign of the result. */
float_type remainder, pi_2; long double remainder, pi_2;
int quadrant; int quadrant;
if ((rx_cond & (__M81_COND_NAN|__M81_COND_NEG)) == __M81_COND_NEG)
__real__ retval = __imag__ retval = 0.0;
else
__real__ retval = __imag__ retval = __real__ x;
__asm ("fmovecr %#0,%0\n\tfscale%.w %#-1,%0" : "=f" (pi_2)); __asm ("fmovecr %#0,%0\n\tfscale%.w %#-1,%0" : "=f" (pi_2));
__asm ("fmod%.x %2,%0\n\tfmove%.l %/fpsr,%1" __asm ("fmod%.x %2,%0\n\tfmove%.l %/fpsr,%1"
: "=f" (remainder), "=dm" (quadrant) : "=f" (remainder), "=dm" (quadrant)
@ -83,7 +104,7 @@ s(__cexp) (__complex__ float_type x)
__imag__ retval = -__imag__ retval; __imag__ retval = -__imag__ retval;
break; break;
} }
if (ix_cond & __M81_COND_ZERO && !m81(__isnan) (exp_val)) if (ix_cond & __M81_COND_ZERO && (rx_cond & __M81_COND_NAN) == 0)
__imag__ retval = __imag__ x; __imag__ retval = __imag__ x;
} }
} }