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Table Driven Break Offset Mapping

IP.com Disclosure Number: IPCOM000082033D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Frye, HE: AUTHOR [+2]

Abstract

Break offset mapping provides a means for debugging programs written in a High Level Language (HLL). A single instruction in a HLL may correspond to many machine instructions. The basis of table driven break off-set mapping is a table, which indicates which machine instruction corresponds to the beginning (or end) of a HLL instruction. When a machine instruction which corresponds to an entry in the table is executed, the machine interrupts program execution and initiates a testing services routine.

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Table Driven Break Offset Mapping

Break offset mapping provides a means for debugging programs written in a High Level Language (HLL). A single instruction in a HLL may correspond to many machine instructions. The basis of table driven break off-set mapping is a table, which indicates which machine instruction corresponds to the beginning (or end) of a HLL instruction. When a machine instruction which corresponds to an entry in the table is executed, the machine interrupts program execution and initiates a testing services routine.

A HLL processor, which generates intermediate text for a Lower Level Language processor, inserts a BREAK statement after each group of statements which corresponds to a single HLL source statement. The BREAK operators demarcate HLL processor-generated source statement code groups and have as an operand an identifier for the HLL.

The lowest level processor, which generates machine executable code, builds a Break Offset Map (BOM) table for each level of intermediate text. The BOM tables can take on several different forms, two of which are described below.

In the first form, a BOM table consists of the displacements relative to the beginning of the module of those instructions corresponding to break points for a given level of code. When the module is loaded into storage, these relative displacements are converted to absolute addresses as determined by the location where the start of the module is located.

To avoid having to scan the table bef...