projects / OpenSPARC-T2-SAM / blame
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|---|---|---|
| 920dae64 AT |
1 | /* |
| 2 | * ========== Copyright Header Begin ========================================== | |
| 3 | * | |
| 4 | * Hypervisor Software File: checksum.c | |
| 5 | * | |
| 6 | * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. | |
| 7 | * | |
| 8 | * - Do no alter or remove copyright notices | |
| 9 | * | |
| 10 | * - Redistribution and use of this software in source and binary forms, with | |
| 11 | * or without modification, are permitted provided that the following | |
| 12 | * conditions are met: | |
| 13 | * | |
| 14 | * - Redistribution of source code must retain the above copyright notice, | |
| 15 | * this list of conditions and the following disclaimer. | |
| 16 | * | |
| 17 | * - Redistribution in binary form must reproduce the above copyright notice, | |
| 18 | * this list of conditions and the following disclaimer in the | |
| 19 | * documentation and/or other materials provided with the distribution. | |
| 20 | * | |
| 21 | * Neither the name of Sun Microsystems, Inc. or the names of contributors | |
| 22 | * may be used to endorse or promote products derived from this software | |
| 23 | * without specific prior written permission. | |
| 24 | * | |
| 25 | * This software is provided "AS IS," without a warranty of any kind. | |
| 26 | * ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, | |
| 27 | * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A | |
| 28 | * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN | |
| 29 | * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR | |
| 30 | * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR | |
| 31 | * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN | |
| 32 | * OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR | |
| 33 | * FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE | |
| 34 | * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, | |
| 35 | * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF | |
| 36 | * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. | |
| 37 | * | |
| 38 | * You acknowledge that this software is not designed, licensed or | |
| 39 | * intended for use in the design, construction, operation or maintenance of | |
| 40 | * any nuclear facility. | |
| 41 | * | |
| 42 | * ========== Copyright Header End ============================================ | |
| 43 | */ | |
| 44 | /* | |
| 45 | * id: @(#)checksum.c 1.9 01/03/04 | |
| 46 | * purpose: Flash PROM Update Utility | |
| 47 | * copyright: Copyright 1995-2001 Sun Microsystems, Inc. All Rights Reserved | |
| 48 | */ | |
| 49 | ||
| 50 | #include <sys/types.h> | |
| 51 | ||
| 52 | uint16_t | |
| 53 | checksum(uint16_t *addr, int32_t count) | |
| 54 | { | |
| 55 | ||
| 56 | /* | |
| 57 | * Compute Internet Checksum for "count" bytes beginning at | |
| 58 | * location "addr". | |
| 59 | */ | |
| 60 | register uint32_t sum = 0; | |
| 61 | ||
| 62 | while (count > 1) { | |
| 63 | /* This is the inner loop */ | |
| 64 | sum += *addr++; | |
| 65 | count -= 2; | |
| 66 | } | |
| 67 | ||
| 68 | /* Add left-over byte, if any */ | |
| 69 | if (count > 0) | |
| 70 | sum += *(unsigned char *) addr; | |
| 71 | ||
| 72 | /* Fold 32-bit sum to 16 bits */ | |
| 73 | while (sum >> 16) { | |
| 74 | sum = (sum & 0xffff) + (sum >> 16); | |
| 75 | } | |
| 76 | ||
| 77 | sum = (~sum) & 0xffff; | |
| 78 | if (sum == 0) | |
| 79 | sum = 0xffff; | |
| 80 | return (sum); | |
| 81 | } |