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