projects / thirdparty / u-boot.git / blame
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1 | .. SPDX-License-Identifier: GPL-2.0+: |
| 2 | ||
| 60971e63 HS |
3 | .. index:: |
| 4 | single: cmp (command) | |
| 5 | ||
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6 | cmp command |
| 7 | =========== | |
| 8 | ||
| 9 | Synopsis | |
| 10 | -------- | |
| 11 | ||
| 12 | :: | |
| 13 | ||
| 14 | cmp [.b, .w, .l, .q] addr1 addr2 count | |
| 15 | ||
| 16 | Description | |
| 17 | ----------- | |
| 18 | ||
| 19 | The cmp command is used to compare two memory areas. By default it works on | |
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20 | four byte (32-bit) values. By appending .b, .w, .l, .q the size of the |
| 21 | values is controlled: | |
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22 | |
| 23 | cmp.b | |
| a356b50f | 24 | compare 1 byte (8-bit) values |
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25 | |
| 26 | cmp.w | |
| a356b50f | 27 | compare 2 byte (16-bit) values |
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28 | |
| 29 | cmp.l | |
| a356b50f | 30 | compare 4 byte (32-bit) values |
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31 | |
| 32 | cmp.q | |
| a356b50f | 33 | compare 8 byte (64-bit) values |
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34 | |
| 35 | The parameters are used as follows: | |
| 36 | ||
| 37 | addr1 | |
| 38 | Address of the first memory area. | |
| 39 | ||
| 40 | addr2 | |
| 41 | Address of the second memory area. | |
| 42 | ||
| 43 | count | |
| 44 | Number of bytes to compare (as hexadecimal number). | |
| 45 | ||
| 46 | Example | |
| 47 | ------- | |
| 48 | ||
| 49 | In the example below the strings "Hello world\n" and "Hello World\n" are written | |
| 50 | to memory and then compared. | |
| 51 | ||
| 52 | :: | |
| 53 | ||
| 54 | => mm.b 0x1000000 | |
| 55 | 01000000: 00 ? 48 | |
| 56 | 01000001: 00 ? 65 | |
| 57 | 01000002: 00 ? 6c | |
| 58 | 01000003: 00 ? 6c | |
| 59 | 01000004: 00 ? 6f | |
| 60 | 01000005: 00 ? 20 | |
| 61 | 01000006: 00 ? 77 | |
| 62 | 01000007: 00 ? 6f | |
| 63 | 01000008: 00 ? 72 | |
| 64 | 01000009: 00 ? 6c | |
| 65 | 0100000a: 00 ? 64 | |
| 66 | 0100000b: 00 ? 0d | |
| 67 | 0100000c: 00 ? => <INTERRUPT> | |
| 68 | => mm.b 0x101000 | |
| 69 | 00101000: 00 ? 48 | |
| 70 | 00101001: 00 ? 65 | |
| 71 | 00101002: 00 ? 6c | |
| 72 | 00101003: 00 ? 6c | |
| 73 | 00101004: 00 ? 6f | |
| 74 | 00101005: 00 ? 20 | |
| 75 | 00101006: 00 ? 57 | |
| 76 | 00101007: 00 ? 6f | |
| 77 | 00101008: 00 ? 72 | |
| 78 | 00101009: 00 ? 6c | |
| 79 | 0010100a: 00 ? 64 | |
| 80 | 0010100b: 00 ? 0d | |
| 81 | 0010100c: 00 ? => <INTERRUPT> | |
| 82 | => cmp 0x1000000 0x101000 0xc | |
| 83 | word at 0x01000004 (0x6f77206f) != word at 0x00101004 (0x6f57206f) | |
| 84 | Total of 1 word(s) were the same | |
| 85 | => cmp.b 0x1000000 0x101000 0xc | |
| 86 | byte at 0x01000006 (0x77) != byte at 0x00101006 (0x57) | |
| 87 | Total of 6 byte(s) were the same | |
| 88 | => cmp.w 0x1000000 0x101000 0xc | |
| 89 | halfword at 0x01000006 (0x6f77) != halfword at 0x00101006 (0x6f57) | |
| 90 | Total of 3 halfword(s) were the same | |
| 91 | => cmp.l 0x1000000 0x101000 0xc | |
| 92 | word at 0x01000004 (0x6f77206f) != word at 0x00101004 (0x6f57206f) | |
| 93 | Total of 1 word(s) were the same | |
| 94 | => cmp.q 0x1000000 0x101000 0xc | |
| 95 | double word at 0x01000000 (0x6f77206f6c6c6548) != double word at 0x00101000 (0x6f57206f6c6c6548) | |
| 96 | Total of 0 double word(s) were the same | |
| 97 | ||
| 98 | Configuration | |
| 99 | ------------- | |
| 100 | ||
| 101 | The cmp command is only available if CONFIG_CMD_MEMORY=y. The cmp.q command is | |
| 102 | only available if additionally CONFIG_MEM_SUPPORT_64BIT_DATA=y. | |
| 103 | ||
| 104 | Return value | |
| 105 | ------------ | |
| 106 | ||
| 107 | The return value $? is true (0) if the compared memory areas are equal. | |
| 108 | The reutrn value is false (1) if the compared memory areas differ. |