
UDI Services Overview
2-10
Universal Debugger Interface Specification
It may be necessary for a TIP to allow a user to include symbolic expressions
in the transparent mode commands. The TIP can then ask the DFE (which
controls the symbol table) to map an expression to a value or an address.
Alternatively, the TIP, instead of displaying a raw address to the user in the
output of a transparent mode command, may need to map that raw address to a
symbolic expression. Again, only the DFE can provide this mapping. The TIP
asks the DFE to perform these services by “calling back” to the DFE.
The DFE may require TIP services (such as
UDIRead
) during its evaluation
and it is legal for the DFE to make any UDI call before returning the answer to
the TIP, as long as further transparent mode calls are avoided.
The symbolic mapping functions are:
UDIDFEEvalExpression
Evaluates a symbolic expression returning
either a value or a resource address.
UDIDFEEvalResource
Maps a resource address to an ASCII string of
the form “symbolname” or “symbolname +
offset”.
TIP Access to DFE Screen I/O
This set of functions, new with version 1.3 of UDI, is implemented by the DFE
and called by the TIP. As with all UDI DFE callback functions, the TIP is only
allowed to call these functions while in the process of handling a request from
the DFE.
The DFE screen I/O services are:
UDIDFEPutOutput
Directs output to the DFE screen. An
IOType
parameter indicates whether the output is from the
TIP itself or from a running target program.
UDIDFEGetInput
Gets input from the DFE, and again, an
IOType
parameter indicates whether the input is for the TIP
itself or for the target program.
UDIDFEEndTIPIO
Provides a way for the TIP to indicate a logical
boundary for a set of TIP–directed (as opposed to
target–directed) I/O requests before returning from
the original UDI request made by the DFE.
Possible uses of the functions is this group are: