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Selection of Alternative Subfields for Table-Driven Trace Record Formatting

IP.com Disclosure Number: IPCOM000040337D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Ku, KS: AUTHOR [+2]

Abstract

When processing table-driven code, it is often necessary to select certain parts of the table. This is particularly useful with respect to a trace entry table. The control mechanism described below gives the following branch capabilities: 1) It allows for selection of alternatives on equal and unequal comparisons. 2) It allows for selecting alternative field processing within the table. 3) It allows for selecting alternative line processing within the table. A brief explanation of the table which is used for this example is needed to clarify how the selection of alternative subfields mechanism works. The table contains the information for the formatting of all trace entry types. For each kind of trace entry there are multiple line entries in the table.

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Selection of Alternative Subfields for Table-Driven Trace Record Formatting

When processing table-driven code, it is often necessary to select certain parts of the table. This is particularly useful with respect to a trace entry table. The control mechanism described below gives the following branch capabilities: 1) It allows for selection of alternatives on equal

and unequal comparisons.

2) It allows for selecting alternative field

processing within the table.

3) It allows for selecting alternative line

processing within the table. A brief explanation of the table which is used for this example is needed to clarify how the selection of alternative subfields mechanism works. The table contains the information for the formatting of all trace entry types. For each kind of trace entry there are multiple line entries in the table. Each line entry has a specific purpose in the formatting of a trace entry. There are two types of line entries: the selection control line entry and a data formatting line entry. A line entry may consist of the following type of information: Type Code

Line Number

Field Number

Output Displacement

Compare Data Field

Compare Unequal Action Code

Conversion Routine Address

Input Address

Length The type code field identifies the type of trace entry being processed. The line number field defines the output line number being processed relative to the trace entry currently being worked on. The field number identifies the field number being processed relative to the current line number being processed. The output displacement field is not used in the selection control entry.

The compare data field contains a value that is compared to the input address field. The equal return code and unequal return code fields contain return codes. The conversion routine address field contains the address of the routine (CHKCODE) that compares the input address field to the compare field. The input address contains the address of the input trace entry field that is being compared to the compare field. The length contains the length of the data to be compared. The selection control function of the table driven mechanism works in the following way: The main routine gets a trace entry. It determines the t...