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- .. SPDX-License-Identifier: GPL-2.0+:
- cmp command
- ===========
- Synopsis
- --------
- ::
- cmp [.b, .w, .l, .q] addr1 addr2 count
- Description
- -----------
- The cmp command is used to compare two memory areas. By default it works on
- four byte (32-bit) values. By appending .b, .w, .l, .q the size of the
- values is controlled:
- cmp.b
- compare 1 byte (8-bit) values
- cmp.w
- compare 2 byte (16-bit) values
- cmp.l
- compare 4 byte (32-bit) values
- cmp.q
- compare 8 byte (64-bit) values
- The parameters are used as follows:
- addr1
- Address of the first memory area.
- addr2
- Address of the second memory area.
- count
- Number of bytes to compare (as hexadecimal number).
- Example
- -------
- In the example below the strings "Hello world\n" and "Hello World\n" are written
- to memory and then compared.
- ::
- => mm.b 0x1000000
- 01000000: 00 ? 48
- 01000001: 00 ? 65
- 01000002: 00 ? 6c
- 01000003: 00 ? 6c
- 01000004: 00 ? 6f
- 01000005: 00 ? 20
- 01000006: 00 ? 77
- 01000007: 00 ? 6f
- 01000008: 00 ? 72
- 01000009: 00 ? 6c
- 0100000a: 00 ? 64
- 0100000b: 00 ? 0d
- 0100000c: 00 ? => <INTERRUPT>
- => mm.b 0x101000
- 00101000: 00 ? 48
- 00101001: 00 ? 65
- 00101002: 00 ? 6c
- 00101003: 00 ? 6c
- 00101004: 00 ? 6f
- 00101005: 00 ? 20
- 00101006: 00 ? 57
- 00101007: 00 ? 6f
- 00101008: 00 ? 72
- 00101009: 00 ? 6c
- 0010100a: 00 ? 64
- 0010100b: 00 ? 0d
- 0010100c: 00 ? => <INTERRUPT>
- => cmp 0x1000000 0x101000 0xc
- word at 0x01000004 (0x6f77206f) != word at 0x00101004 (0x6f57206f)
- Total of 1 word(s) were the same
- => cmp.b 0x1000000 0x101000 0xc
- byte at 0x01000006 (0x77) != byte at 0x00101006 (0x57)
- Total of 6 byte(s) were the same
- => cmp.w 0x1000000 0x101000 0xc
- halfword at 0x01000006 (0x6f77) != halfword at 0x00101006 (0x6f57)
- Total of 3 halfword(s) were the same
- => cmp.l 0x1000000 0x101000 0xc
- word at 0x01000004 (0x6f77206f) != word at 0x00101004 (0x6f57206f)
- Total of 1 word(s) were the same
- => cmp.q 0x1000000 0x101000 0xc
- double word at 0x01000000 (0x6f77206f6c6c6548) != double word at 0x00101000 (0x6f57206f6c6c6548)
- Total of 0 double word(s) were the same
- Configuration
- -------------
- The cmp command is only available if CONFIG_CMD_MEMORY=y. The cmp.q command is
- only available if additionally CONFIG_MEM_SUPPORT_64BIT_DATA=y.
- Return value
- ------------
- The return value $? is true (0) if the compared memory areas are equal.
- The reutrn value is false (1) if the compared memory areas differ.
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