projects / unix-history / blame
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1 | /*- |
| 2 | * Copyright (c) 1985 The 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 | * | |
| c0567266 KB |
8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions | |
| 10 | * are met: | |
| 11 | * 1. Redistributions of source code must retain the above copyright | |
| 12 | * notice, this list of conditions and the following disclaimer. | |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright | |
| 14 | * notice, this list of conditions and the following disclaimer in the | |
| 15 | * documentation and/or other materials provided with the distribution. | |
| 16 | * 3. All advertising materials mentioning features or use of this software | |
| 17 | * must display the following acknowledgement: | |
| 18 | * This product includes software developed by the University of | |
| 19 | * California, Berkeley and its contributors. | |
| 20 | * 4. Neither the name of the University nor the names of its contributors | |
| 21 | * may be used to endorse or promote products derived from this software | |
| 22 | * without specific prior written permission. | |
| 23 | * | |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 34 | * SUCH DAMAGE. | |
| af359dea C |
35 | * |
| 36 | * @(#)Kfnorm.s 7.1 (Berkeley) 12/6/90 | |
| 7c27088c | 37 | */ |
| 3c2fd3a8 | 38 | |
| a6730a00 KB |
39 | #include "../math/fp.h" |
| 40 | #include "../math/Kfp.h" | |
| 9d1834ba | 41 | #include "../tahoe/SYS.h" |
| 3c2fd3a8 SL |
42 | |
| 43 | .text | |
| 2b252132 | 44 | ENTRY(Kfnorm, R6|R5|R4|R3|R2) |
| 3c2fd3a8 SL |
45 | # clrl r1 |
| 46 | movl r0,r4 # copy to temporary. | |
| 47 | jneq inr0 | |
| 48 | movl r1,r5 | |
| 49 | clrl r3 # r3 - pos of m.s.b | |
| 50 | inr1: ffs r5,r6 | |
| 51 | incl r6 | |
| 52 | addl2 r6,r3 | |
| 53 | shrl r6,r5,r5 | |
| 54 | jneq inr1 | |
| 55 | cmpl $0,r3 | |
| 56 | jeql retzero | |
| 57 | jmp cmpshift | |
| 58 | inr0: movl $32,r3 | |
| 59 | inr00: ffs r4,r6 | |
| 60 | incl r6 | |
| 61 | addl2 r6,r3 | |
| 62 | shrl r6,r4,r4 | |
| 63 | jneq inr00 | |
| 64 | ||
| 65 | cmpshift: | |
| 66 | # compute the shift (r4). | |
| 67 | subl3 r3,$HID_R0R1,r4 | |
| 68 | jlss shiftr # if less then zero we shift right. | |
| 69 | shlq r4,r0,r0 # else we shift left. | |
| 70 | subl2 r4,r2 # uodate exponent. | |
| 71 | jleq underflow # if less then 0 (biased) it is underflow. | |
| 72 | jmp combine # go to combine exponent and fraction. | |
| 73 | shiftr: | |
| 74 | mnegl r4,r4 | |
| 75 | shrq r4,r0,r0 # shift right. | |
| 76 | addl2 r4,r2 # update exponent | |
| 77 | cmpl r2,$256 | |
| 78 | jgeq overflow # check for overflow. | |
| 79 | combine: | |
| 80 | andl2 $CLEARHID,r0 # clear the hidden bit. | |
| 81 | shal $EXPSHIFT,r2,r2 # shift the exponent to its proper place. | |
| 82 | orl2 r2,r0 | |
| 83 | ret | |
| 84 | ||
| 85 | underflow: | |
| 86 | clrl r0 | |
| 87 | orl2 $HFS_UNDF,*4(fp) | |
| 88 | ret | |
| 89 | ||
| 90 | overflow: | |
| 91 | orl2 $HFS_OVF,*4(fp) | |
| 92 | ret | |
| 93 | retzero: | |
| 94 | clrl r0 | |
| 95 | clrl r1 | |
| 96 | ret |