/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/asm_linkage.h>

        .file   "fsr.s"
        .ident  ""

        .section        .data
        .align 4

/*
 * The following table maps trap enable bits in __fsr_init_value
 * (after shifting right one bit):
 *
 * bit 0 - inexact trap
 * bit 1 - division trap
 * bit 2 - underflow trap
 * bit 3 - overflow trap
 * bit 4 - invalid trap
 *
 * to exception masks in the floating point control word
 *
 * bit 0 - invalid mask
 * bit 2 - zero divide mask
 * bit 3 - overflow mask
 * bit 4 - underflow mask
 * bit 5 - inexact mask
 */
        .local  trap_table
        .type   trap_table,@object
trap_table:
        .byte   0b11111111
        .byte   0b11011111
        .byte   0b11111011
        .byte   0b11011011
        .byte   0b11101111
        .byte   0b11001111
        .byte   0b11101011
        .byte   0b11001011
        .byte   0b11110111
        .byte   0b11010111
        .byte   0b11110011
        .byte   0b11010011
        .byte   0b11100111
        .byte   0b11000111
        .byte   0b11100011
        .byte   0b11000011
        .byte   0b11111110
        .byte   0b11011110
        .byte   0b11111010
        .byte   0b11011010
        .byte   0b11101110
        .byte   0b11001110
        .byte   0b11101010
        .byte   0b11001010
        .byte   0b11110110
        .byte   0b11010110
        .byte   0b11110010
        .byte   0b11010010
        .byte   0b11100110
        .byte   0b11000110
        .byte   0b11100010
        .byte   0b11000010

        .size   trap_table,32

ENTRY_NP(__fsr)
        pushl   %ebp
        movl    %esp,%ebp
        pushl   %edx
        pushl   %ecx
        pushl   %ebx
        subl    $4,%esp

        /* Setup PIC */
        call    9f
9:      popl    %ebx
        addl    $_GLOBAL_OFFSET_TABLE_ + [. - 9b], %ebx

        movl    8(%ebp), %ecx           /* the value set by CG is passed in */
        shrl    $1,%ecx                 /* get rid of fns bit */
        cmpl    $0,%ecx                 /* if remaining bits are zero */
        je      3f                      /*   there's nothing to do */

        fstcw   0(%esp)                 /* store the control word */

        movl    %ecx,%edx
        andl    $0x1f,%edx              /* get the trap enable bits */
        movl    trap_table@GOT(%ebx), %eax
        addl    %eax,%edx
        movb    (%edx),%al
        andb    %al,0(%esp)     /* unmask the corresponding exceptions */

        testl   $0x200,%ecx             /* test denormal trap enable */
        jz      1f                      /* skip if zero */

        andb    $0xfd,0(%esp)   /* unmask denormal exception */

1:
        movl    %ecx,%edx
        andl    $0x60,%edx              /* get the rounding direction */
        jz      1f                      /* skip if zero */

        movl    %edx,%eax               /* exchange negative<->tozero */
        andl    $0x20,%eax              /*   leaving nearest and positive */
        shll    $1,%eax                 /*   as is */
        xorl    %eax,%edx
        shll    $5,%edx
        andw    $0xf3ff,0(%esp)         /* update rounding direction */
        orw     %dx,0(%esp)

1:
        andl    $0x180,%ecx             /* get the rounding precision */
        jz      1f                      /* skip if zero */

        xorl    $0x180,%ecx             /* reverse bits */
        shll    $1,%ecx
        andw    $0xfcff,0(%esp)         /* update rounding precision */
        orw     %cx,0(%esp)

1:
        fldcw   0(%esp)                 /* load the modified control word */

3:
        addl    $4,%esp
        popl    %ebx
        popl    %ecx
        popl    %edx
        popl    %ebp
        ret
SET_SIZE(__fsr)