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systmodes.S revision 1.2 
      1 /* $NetBSD: systmodes.S,v 1.2 2001/03/13 07:41:26 ross Exp $ */
      2 
      3 /* This is a derivative work. */
      4 
      5 /*-
      6  * Copyright (c) 2001 The NetBSD Foundation, Inc.
      7  * All rights reserved.
      8  *
      9  * This code is derived from software contributed to The NetBSD Foundation
     10  * by Ross Harvey.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *        This product includes software developed by the NetBSD
     23  *        Foundation, Inc. and its contributors.
     24  * 4. Neither the name of The NetBSD Foundation nor the names of its
     25  *    contributors may be used to endorse or promote products derived
     26  *    from this software without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     29  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     30  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     31  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     32  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     33  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     34  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     35  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     36  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     37  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     38  * POSSIBILITY OF SUCH DAMAGE.
     39  */
     40 
     41 /*
     42 ===============================================================================
     43 
     44 This GNU assembler source file is part of TestFloat, Release 2a, a package
     45 of programs for testing the correctness of floating-point arithmetic
     46 complying to the IEC/IEEE Standard for Floating-Point.
     47 
     48 Written by John R. Hauser.  More information is available through the Web
     49 page `http://HTTP.CS.Berkeley.EDU/~jhauser/arithmetic/TestFloat.html'.
     50 
     51 THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort
     52 has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
     53 TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO
     54 PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
     55 AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
     56 
     57 Derivative works are acceptable, even for commercial purposes, so long as
     58 (1) they include prominent notice that the work is derivative, and (2) they
     59 include prominent notice akin to these four paragraphs for those parts of
     60 this code that are retained.
     61 
     62 ===============================================================================
     63 */
     64 
     65 	.text
     66 
     67 /*
     68 -------------------------------------------------------------------------------
     69 Sets the system's IEC/IEEE floating-point rounding mode.  Also disables all
     70 system exception traps.
     71 -------------------------------------------------------------------------------
     72 */
     73 
     74 #include <machine/asm.h>
     75 
     76 ENTRY(syst_float_set_rounding_mode)
     77 	movb 4(%esp),%al
     78 	andb $3,%al
     79 	shlw $10,%ax
     80 	orw $63,%ax
     81 	subl $2,%esp
     82 	fnstcw 0(%esp)
     83 	andw $768,0(%esp)
     84 	orw %ax,0(%esp)
     85 	fldcw 0(%esp)
     86 	addl $2,%esp
     87 	ret
     88 
     89 /*
     90 -------------------------------------------------------------------------------
     91 Sets the rounding precision of subsequent extended double-precision
     92 operations.  The `precision' argument should be one of 0, 32, 64, or 80.
     93 If `precision' is 32, the rounding precision is set equivalent to single
     94 precision; else if `precision' is 64, the rounding precision is set
     95 equivalent to double precision; else the rounding precision is set to full
     96 extended double precision.
     97 -------------------------------------------------------------------------------
     98 */
     99 
    100 ENTRY(syst_float_set_rounding_precision)
    101 	movb 4(%esp),%al
    102 	movb $0,%ah
    103 	cmpb $32,%al
    104 	je setRoundingPrecision
    105 	movb $2,%ah
    106 	cmpb $64,%al
    107 	je setRoundingPrecision
    108 	movb $3,%ah
    109 	cmpb $80,%al
    110 	je setRoundingPrecision
    111 	movb $0,%ah
    112 setRoundingPrecision:
    113 	movb $0,%al
    114 	subl $2,%esp
    115 	fnstcw 0(%esp)
    116 	andw $64767,0(%esp)
    117 	orw %ax,0(%esp)
    118 	fldcw 0(%esp)
    119 	addl $2,%esp
    120 	ret
    121 
    122