diff options
Diffstat (limited to 'test/math/eexp.c')
-rw-r--r-- | test/math/eexp.c | 154 |
1 files changed, 77 insertions, 77 deletions
diff --git a/test/math/eexp.c b/test/math/eexp.c index dd2a64e1c..14ea9899d 100644 --- a/test/math/eexp.c +++ b/test/math/eexp.c @@ -1,77 +1,77 @@ -/* xexp.c */
-/* exponential function check routine */
-/* by Stephen L. Moshier. */
-
-
-#include "ehead.h"
-
-/*
-extern int powinited;
-extern short maxposint[], maxnegint[];
-*/
-
-void eexp( x, y )
-unsigned short *x, *y;
-{
-unsigned short num[NE], den[NE], x2[NE];
-long i;
-unsigned short sign, expchk;
-
-/* range reduction theory: x = i + f, 0<=f<1;
- * e**x = e**i * e**f
- * e**i = 2**(i/log 2).
- * Let i/log2 = i1 + f1, 0<=f1<1.
- * Then e**i = 2**i1 * 2**f1, so
- * e**x = 2**i1 * e**(log 2 * f1) * e**f.
- */
-/*
-if( powinited == 0 )
- initpow();
-*/
-if( ecmp(x, ezero) == 0 )
- {
- emov( eone, y );
- return;
- }
-emov(x, x2);
-expchk = x2[NE-1];
-sign = expchk & 0x8000;
-x2[NE-1] &= 0x7fff;
-
-/* Test for excessively large argument */
-expchk &= 0x7fff;
-if( expchk > (EXONE + 15) )
- {
- eclear( y );
- if( sign == 0 )
- einfin( y );
- return;
- }
-
-eifrac( x2, &i, num ); /* x = i + f */
-
-if( i != 0 )
- {
- ltoe( &i, den ); /* floating point i */
- ediv( elog2, den, den ); /* i/log 2 */
- eifrac( den, &i, den ); /* i/log 2 = i1 + f1 */
- emul( elog2, den, den ); /* log 2 * f1 */
- eadd( den, num, x2 ); /* log 2 * f1 + f */
- }
-
-/*x2[NE-1] -= 1;*/
-eldexp( x2, -1L, x2 ); /* divide by 2 */
-etanh( x2, x2 ); /* tanh( x/2 ) */
-eadd( x2, eone, num ); /* 1 + tanh */
-eneg( x2 );
-eadd( x2, eone, den ); /* 1 - tanh */
-ediv( den, num, y ); /* (1 + tanh)/(1 - tanh) */
-
-/*y[NE-1] += i;*/
-if( sign )
- {
- ediv( y, eone, y );
- i = -i;
- }
-eldexp( y, i, y ); /* multiply by 2**i */
-}
+/* xexp.c */ +/* exponential function check routine */ +/* by Stephen L. Moshier. */ + + +#include "ehead.h" + +/* +extern int powinited; +extern short maxposint[], maxnegint[]; +*/ + +void eexp( x, y ) +unsigned short *x, *y; +{ +unsigned short num[NE], den[NE], x2[NE]; +long i; +unsigned short sign, expchk; + +/* range reduction theory: x = i + f, 0<=f<1; + * e**x = e**i * e**f + * e**i = 2**(i/log 2). + * Let i/log2 = i1 + f1, 0<=f1<1. + * Then e**i = 2**i1 * 2**f1, so + * e**x = 2**i1 * e**(log 2 * f1) * e**f. + */ +/* +if( powinited == 0 ) + initpow(); +*/ +if( ecmp(x, ezero) == 0 ) + { + emov( eone, y ); + return; + } +emov(x, x2); +expchk = x2[NE-1]; +sign = expchk & 0x8000; +x2[NE-1] &= 0x7fff; + +/* Test for excessively large argument */ +expchk &= 0x7fff; +if( expchk > (EXONE + 15) ) + { + eclear( y ); + if( sign == 0 ) + einfin( y ); + return; + } + +eifrac( x2, &i, num ); /* x = i + f */ + +if( i != 0 ) + { + ltoe( &i, den ); /* floating point i */ + ediv( elog2, den, den ); /* i/log 2 */ + eifrac( den, &i, den ); /* i/log 2 = i1 + f1 */ + emul( elog2, den, den ); /* log 2 * f1 */ + eadd( den, num, x2 ); /* log 2 * f1 + f */ + } + +/*x2[NE-1] -= 1;*/ +eldexp( x2, -1L, x2 ); /* divide by 2 */ +etanh( x2, x2 ); /* tanh( x/2 ) */ +eadd( x2, eone, num ); /* 1 + tanh */ +eneg( x2 ); +eadd( x2, eone, den ); /* 1 - tanh */ +ediv( den, num, y ); /* (1 + tanh)/(1 - tanh) */ + +/*y[NE-1] += i;*/ +if( sign ) + { + ediv( y, eone, y ); + i = -i; + } +eldexp( y, i, y ); /* multiply by 2**i */ +} |