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1aff59a3 | 1 | /* Float floor function, sparc64 version. |
b168057a | 2 | Copyright (C) 2012-2015 Free Software Foundation, Inc. |
1aff59a3 DM |
3 | This file is part of the GNU C Library. |
4 | Contributed by David S. Miller <davem@davemloft.net>, 2012. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
17 | License along with the GNU C Library; if not, see | |
18 | <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include <sysdep.h> | |
21 | ||
22 | /* Since changing the rounding mode is extremely expensive, we | |
23 | try to round up using a method that is rounding mode | |
24 | agnostic. | |
25 | ||
26 | We add then subtract (or subtract than add if the initial | |
27 | value was negative) 2**23 to the value, then subtract it | |
28 | back out. | |
29 | ||
30 | This will clear out the fractional portion of the value. | |
31 | One of two things will happen for non-whole initial values. | |
32 | Either the rounding mode will round it up, or it will be | |
33 | rounded down. If the value started out whole, it will be | |
34 | equal after the addition and subtraction. This means we | |
35 | can accurately detect with one test whether we need to add | |
36 | another 1.0 to round it up properly. | |
37 | ||
38 | We pop constants into the FPU registers using the incoming | |
39 | argument stack slots, since this avoid having to use any | |
40 | PIC references. We also thus avoid having to allocate a | |
41 | register window. | |
42 | ||
43 | VIS instructions are used to facilitate the formation of | |
44 | easier constants, and the propagation of the sign bit. */ | |
45 | ||
46 | #define TWO_TWENTYTHREE 0x4b000000 /* 2**23 */ | |
47 | #define ONE_DOT_ZERO 0x3f800000 /* 1.0 */ | |
48 | ||
49 | #define ZERO %f10 /* 0.0 */ | |
50 | #define SIGN_BIT %f12 /* -0.0 */ | |
51 | ||
52 | ENTRY (__floorf) | |
53 | sethi %hi(TWO_TWENTYTHREE), %o2 | |
54 | sethi %hi(ONE_DOT_ZERO), %o3 | |
55 | fzeros ZERO | |
56 | ||
57 | fnegs ZERO, SIGN_BIT | |
58 | ||
59 | st %o2, [%sp + STACK_BIAS + 128] | |
60 | fabss %f1, %f14 | |
61 | ||
62 | ld [%sp + STACK_BIAS + 128], %f16 | |
63 | fcmps %fcc3, %f14, %f16 | |
64 | ||
65 | fmovsuge %fcc3, ZERO, %f16 | |
66 | fands %f1, SIGN_BIT, SIGN_BIT | |
67 | ||
68 | fors %f16, SIGN_BIT, %f16 | |
69 | fadds %f1, %f16, %f5 | |
70 | fsubs %f5, %f16, %f5 | |
71 | fcmps %fcc2, %f5, %f1 | |
72 | st %o3, [%sp + STACK_BIAS + 128] | |
73 | ||
74 | ld [%sp + STACK_BIAS + 128], %f9 | |
75 | fmovsule %fcc2, ZERO, %f9 | |
76 | fsubs %f5, %f9, %f0 | |
77 | fabss %f0, %f0 | |
78 | retl | |
79 | fors %f0, SIGN_BIT, %f0 | |
80 | END (__floorf) | |
81 | weak_alias (__floorf, floorf) |