projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 1f0502d3 | 1 | /* |
| aaea5b2e KB |
2 | * Copyright (c) 1986, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. | |
| 1f0502d3 KB |
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. | |
| 1f0502d3 KB |
35 | */ |
| 36 | ||
| 37 | #if defined(SYSLIBC_SCCS) && !defined(lint) | |
| ad787160 | 38 | .asciz "@(#)cvtld.s 8.1 (Berkeley) 6/4/93" |
| 1f0502d3 | 39 | #endif /* SYSLIBC_SCCS and not lint */ |
| c13f0b2e SL |
40 | |
| 41 | #include <tahoemath/fp.h> | |
| 42 | #include "DEFS.h" | |
| 43 | ||
| 44 | XENTRY(cvtld, R2|R3|R4|R5) | |
| 45 | # | |
| 46 | #Some initializations: | |
| 47 | # | |
| 48 | clrl r4 # r4 - negative flag. | |
| 49 | clrl r2 # r2 - exponent. | |
| 50 | movl 4(fp),r0 # fetch operand. | |
| 51 | movl r0,r5 # need another copy. | |
| 52 | jeql retzero # return zero. | |
| 53 | jgtr positive | |
| 54 | mnegl r0,r0 | |
| 55 | jvs retmin # return minimum integer. | |
| 56 | incl r4 # remember it was negative. | |
| 57 | movl r0,r5 # remember the negated value. | |
| 58 | # | |
| 59 | #Compute exponent: | |
| 60 | # | |
| 61 | positive: | |
| 62 | ffs r0,r1 | |
| 63 | incl r1 | |
| 64 | addl2 r1,r2 | |
| 65 | shrl r1,r0,r0 | |
| 66 | jneq positive # look for more set bits. | |
| 67 | # | |
| 68 | #we have the exponent in r2. | |
| 69 | # | |
| 70 | movl r5,r0 # r0,r1 will hold the resulting f.p. number. | |
| 71 | clrl r1 | |
| 72 | # | |
| 73 | #Shift the fraction part to its proper place: | |
| 74 | # | |
| 75 | subl3 r2,$HID_POS,r3 | |
| 76 | jlss shiftr # if less then zero we have to shift right. | |
| 77 | shll r3,r0,r0 # else we shift left. | |
| 78 | jmp shifted | |
| 79 | shiftr: | |
| 80 | mnegl r3,r3 | |
| 81 | shrq r3,r0,r0 | |
| 82 | shifted: | |
| 83 | andl2 $CLEARHID,r0 # clear the hidden bit. | |
| 84 | shal $EXPSHIFT,r2,r2 # shift the exponent to its proper place. | |
| 85 | orl2 $EXPSIGN,r2 # set the exponent sign bit(to bias it). | |
| 86 | orl2 r2,r0 # combine exponent & fraction. | |
| 87 | bbc $0,r4,sign_ok # do we have to set the sign bit? | |
| 88 | orl2 $SIGNBIT,r0 # yes... | |
| 89 | sign_ok: | |
| 90 | ret | |
| 91 | ||
| 92 | retzero: | |
| 93 | clrl r0 | |
| 94 | clrl r1 | |
| 95 | ret | |
| 96 | ||
| 97 | retmin: | |
| 98 | movl $0xd0000000,r0 | |
| 99 | clrl r1 | |
| 100 | ret | |
| 101 | ||
| 102 | ||
| 103 |