diff options
Diffstat (limited to 'lib/libc/amd64/gen/modf.S')
| -rw-r--r-- | lib/libc/amd64/gen/modf.S | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/lib/libc/amd64/gen/modf.S b/lib/libc/amd64/gen/modf.S new file mode 100644 index 0000000..d448de1 --- /dev/null +++ b/lib/libc/amd64/gen/modf.S @@ -0,0 +1,92 @@ +/*- + * Copyright (c) 1990 The Regents of the University of California. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Sean Eric Fagan. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * from: @(#)modf.s 5.5 (Berkeley) 3/18/91 + */ + +#include <machine/asm.h> +#if defined(LIBC_SCCS) + RCSID("$NetBSD: modf.S,v 1.5 1997/07/16 14:37:18 christos Exp $") +#endif +__FBSDID("$FreeBSD$"); + +/* + * modf(value, iptr): return fractional part of value, and stores the + * integral part into iptr (a pointer to double). + * + * Written by Sean Eric Fagan (sef@kithrup.COM) + * Sun Mar 11 20:27:30 PST 1990 + */ + +/* With CHOP mode on, frndint behaves as TRUNC does. Useful. */ +ENTRY(modf) + + /* + * Set chop mode. + */ + fnstcw -12(%rsp) + movw -12(%rsp),%dx + orw $3072,%dx + movw %dx,-16(%rsp) + fldcw -16(%rsp) + + /* + * Get integral part. + */ + movsd %xmm0,-24(%rsp) + fldl -24(%rsp) + frndint + fstpl -8(%rsp) + + /* + * Restore control word. + */ + fldcw -12(%rsp) + + /* + * Store integral part. + */ + movsd -8(%rsp),%xmm0 + movsd %xmm0,(%rdi) + + /* + * Get fractional part and return it. + */ + fldl -24(%rsp) + fsubl -8(%rsp) + fstpl -8(%rsp) + movsd -8(%rsp),%xmm0 + + ret |
