usr/src/lib/libc/tahoe/fpe/negf.s

/*
 * Copyright (c) 1986 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Computer Consoles Inc.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(SYSLIBC_SCCS) && !defined(lint)
        .asciz "@(#)negf.s      1.3 (Berkeley) 6/1/90"
#endif /* SYSLIBC_SCCS and not lint */

#include <tahoemath/fp.h>
#include "DEFS.h"

XENTRY(negf, 0)
        clrl    r1
        andl3   $EXPMASK,4(fp),r0       /* check for reserved operand,zero. */
        beql    isreserved
        movl    4(fp),r0                /* fetch operand. */
        bbc     $31,r0,seton
        andl2   $(0!SIGNBIT),r0         /* turn it off. */
        ret
seton:  orl2    $SIGNBIT,r0             /* turn it on. */
        ret
isreserved:
        bbc     $31,4(fp),retzero
        callf   $4,sfpresop
        ret
retzero:
        clrl    r0
        ret