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5c44784c JM |
1 | /* |
2 | * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved. | |
3 | * | |
4 | * This software may be freely used, copied, modified, and distributed | |
5 | * provided that the above copyright notice is preserved in all copies of the | |
6 | * software. | |
7 | */ | |
8 | ||
9 | /* | |
10 | * angel_bytesex.c - Code to support byte-sex independence | |
11 | * Copyright: (C) 1991, Advanced RISC Machines Ltd., Cambridge, England. | |
12 | */ | |
13 | ||
14 | /* | |
15 | * RCS $Revision$ | |
16 | * Checkin $Date$ | |
17 | */ | |
18 | ||
19 | #include "angel_bytesex.h" | |
20 | ||
21 | static int reversing_bytes = 0; | |
22 | ||
23 | void bytesex_reverse(yes_or_no) | |
24 | int yes_or_no; | |
25 | { reversing_bytes = yes_or_no; | |
26 | } | |
27 | ||
28 | int bytesex_reversing() | |
29 | { | |
30 | return reversing_bytes; | |
31 | } | |
32 | ||
33 | int32 bytesex_hostval(v) | |
34 | int32 v; | |
35 | { /* Return v with the same endian-ness as the host */ | |
36 | /* This mess generates better ARM code than the more obvious mess */ | |
37 | /* and may eventually peephole to optimal code... */ | |
38 | if (reversing_bytes) | |
39 | { unsigned32 t; | |
40 | /* t = v ^ (v ror 16) */ | |
41 | t = v ^ ((v << 16) | (((unsigned32)v) >> 16)); | |
42 | t &= ~0xff0000; | |
43 | /* v = v ror 8 */ | |
44 | v = (v << 24) | (((unsigned32)v) >> 8); | |
45 | v = v ^ (t >> 8); | |
46 | } | |
47 | return v; | |
48 | } | |
49 | ||
50 | int32 bytesex_hostval_16(v) | |
51 | int32 v; | |
52 | { | |
53 | if (reversing_bytes) { | |
54 | v = ((v >> 8) & 0xff) | ((v << 8) & 0xff00); | |
55 | } | |
56 | return v; | |
57 | } |