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96 lines
2.6 KiB
96 lines
2.6 KiB
18 years ago
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The b Command
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b
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The b command sets and displays breakpoints.
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Format
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The format for the b command is:
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b
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b adr..
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b adr -s str
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where:
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adr specifies an address for the breakpoint.
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Up to 32 breakpoints addresses can be set.
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-s str executes the command string when the breakpoint is hit.
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Invoking the b command with no options causes the Monitor to print a list
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of the current breakpoints.
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Functional Description
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The b command sets a breakpoint at the specified
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address or addresses. Multiple addresses may be specified. Specified
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addresses must be word-aligned.
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This command is effectively a "pass-thru" to the
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when command. Issuing the command,
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"b main" is equivalent to issuing the command,
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"when @pc==main stop". However, unlike the
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when command, the b command can
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take multiple addresses.
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The Monitor automatically assigns a number to each breakpoint.
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The Monitor allocates the lowest
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available breakpoint number from 0 to 31 to any new breakpoint.
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The Monitor reports a new breakpoint's number immediately after the
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breakpoint is set (see the examples at the end of this subsection for
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illustration of this). The assigned numbers can be used in the
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db (Delete Breakpoint) command.
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The brkcmd Variable
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When a breakpoint is reached, the command list specified in the
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environment variable brkcmd is executed. The default setting for brkcmd is:
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brkcmd = "l @pc 1"
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This command "l @pc 1", specifies that when the breakpoint
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occurs, the Monitor will disassemble one line starting at the address
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of the program counter.
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You can change the breakpoint command variable with the set command.
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For example, you can include additional monitor commands in the brkcmd
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variable. You must separate additional commands on the command line
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with a semicolon. For example, entering the following command lists one
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line after reaching a breakpoint, and then displays all the register values.
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set brkcmd "l @epc 1;r *"
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By default, breakpoints are cleared when the load command is executed.
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See the section on the load command later in this document for details on
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how to override automatic breakpoint clearing after a download operation.
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Some examples illustrating the use of the b command follow.
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PMON b a002000c Set a breakpoint at 0xa002000c.
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Bpt 1 = a002000c
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PMON b
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Bpt 0 = 8002022c
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Bpt 1 = a002000c
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Display all breakpoints.
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PMON b 80021248 -s "r" Set a breakpoint at 0x80021248. Display registers
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when the breakpoint is encountered.
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See Also
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db,
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when,
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and load commands.
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Navigation:
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Document Home |
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Document Contents |
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Document Index
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