ack/mach/proto/fp/sbf8.c

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1988-04-07 11:40:46 +00:00
/*
(c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
1988-04-07 10:57:49 +00:00
/*
SUBTRACT TWO FLOATS - DOUBLE Precision
*/
#include "FP_types.h"
extern _double adf8();
_double
sbf8(s2,s1)
_double s1,s2;
{
/* changing the sign directly */
/* is faster than the code line */
/* s2 = -s2; */
char unsigned *p; /* sufficient to access sign bit */
#ifdef PRT_EXT
fprintf(stderr,"SBF8 ():\n");
#endif
p = (char unsigned *) &s2;
*p ^= 0x80; /* change sign of s2 */
s1 = adf8(s2,s1); /* add and return result */
return(s1);
}