HP 1660CS, User Manual

Page: 53 / 347

The Inverse Assembler
When the analyzer captures a trace, it captures binary information.
The analyzer can then present this information in symbol, binary,
octal, decimal, hexadecimal, or ASCII. Or, if given information about
the meaning of the data captured, the analyzer can inverse assemble
the trace. The inverse assembler makes the trace list more readable
by presenting the trace results in terms of processor opcodes and data
transactions.
To use an inverse assembler
Most preprocessors include an inverse assembler in their software. Loading
the configuration file for the preprocessor sets up the logic analyzer to
provide certain types of information for the inverse assembler. This section
is provided in case you ever have to set up an analyzer for inverse assembly
yourself.
The inverse assembly software needs at least these five pieces of information:
•
Address bus. The inverse assembler expects to see the label ADDR, with
bits ordered in a particular sequence.
•
Data bus. The inverse assembler expects to see the label DATA, with bits
ordered in a particular sequence.
•
Status. The inverse assembler expects to see the label STAT, with bits
ordered in a particular sequence.
•
Start state for disassembly. This is the first displayed state in the trace list,
not the cursor position. See the figure on the next page.
•
Tables indicating the meaning of particular status and data combinations.
The particular sequences that each label requires depends on the type of
chip the inverse assembler was designed for. Because of this, inverse
assemblers cannot generally be transferred between platforms.
To run the inverse assembler, you must be sure the labels are spelled
correctly as shown here, or as directed in your inverse assembler
documentation. Even a minor difference such as not capitalizing each letter
will cause the inverse assembler to not work.
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