Return to fnorm.s CVS log

Up to [CSRG BSD Unix] / 43BSDReno / lib / libc / tahoe / fpe

Annotation of 43BSDReno/lib/libc/tahoe/fpe/fnorm.s, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1986 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * This code is derived from software contributed to Berkeley by
        !             6:  * Computer Consoles Inc.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms are permitted
        !             9:  * provided that: (1) source distributions retain this entire copyright
        !            10:  * notice and comment, and (2) distributions including binaries display
        !            11:  * the following acknowledgement:  ``This product includes software
        !            12:  * developed by the University of California, Berkeley and its contributors''
        !            13:  * in the documentation or other materials provided with the distribution
        !            14:  * and in all advertising materials mentioning features or use of this
        !            15:  * software. Neither the name of the University nor the names of its
        !            16:  * contributors may be used to endorse or promote products derived
        !            17:  * from this software without specific prior written permission.
        !            18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            19:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            20:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            21:  */
        !            22: 
        !            23: #if defined(SYSLIBC_SCCS) && !defined(lint)
        !            24:        .asciz "@(#)fnorm.s     1.3 (Berkeley) 6/1/90"
        !            25: #endif /* SYSLIBC_SCCS and not lint */
        !            26: 
        !            27: #include <tahoemath/fp.h>
        !            28: #include "DEFS.h"
        !            29: 
        !            30: ENTRY(fnorm, R2|R3|R4|R5|R6)
        !            31:        movl    r0,r4           # copy to temporary.
        !            32:        jneq    inr0
        !            33:        movl    r1,r5
        !            34:        clrl    r3              # r3 - pos of m.s.b
        !            35: inr1:  ffs     r5,r6
        !            36:        incl    r6
        !            37:        addl2   r6,r3
        !            38:        shrl    r6,r5,r5
        !            39:        jneq    inr1
        !            40:        cmpl    $0,r3
        !            41:        jeql    retzero
        !            42:        jmp     cmpshift
        !            43: inr0:  movl    $32,r3
        !            44: inr00: ffs     r4,r6
        !            45:        incl    r6
        !            46:        addl2   r6,r3
        !            47:        shrl    r6,r4,r4
        !            48:        jneq    inr00
        !            49: 
        !            50: cmpshift:
        !            51:                                # compute the shift (r4).
        !            52:        subl3   r3,$HID_R0R1,r4
        !            53:        jlss    shiftr          # if less then zero we shift right.
        !            54:        shlq    r4,r0,r0        # else we shift left.
        !            55:        subl2   r4,r2           # uodate exponent.
        !            56:        jleq    underflow       # if less then 0 (biased) it is underflow.
        !            57:        jmp     combine         # go to combine exponent and fraction.
        !            58: shiftr:
        !            59:        mnegl   r4,r4
        !            60:        shrq    r4,r0,r0        # shift right.
        !            61:        addl2   r4,r2           # update exponent
        !            62:        cmpl    r2,$256
        !            63:        jgeq    overflow        # check for overflow.
        !            64: combine:
        !            65:        andl2   $CLEARHID,r0    # clear the hidden bit.
        !            66:        shal    $EXPSHIFT,r2,r2 # shift the exponent to its proper place.
        !            67:        orl2    r2,r0
        !            68:        ret
        !            69: 
        !            70: underflow:
        !            71:        callf   $4,fpunder
        !            72:        ret
        !            73: 
        !            74: overflow:
        !            75:        callf   $4,fpover
        !            76:        ret
        !            77: retzero:
        !            78:        clrl    r0
        !            79:        clrl    r1
        !            80:        ret

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.