Table of Contents
Advertisement
Line-Number Table Structure
A.6 Line-Number Table Structure
Table A–9. Line-Number Entry Format
Figure A–4. Line-Number Blocks
A-12
The object file contains a table of line-number entries that are useful for
symbolic debugging. When the C compiler produces several lines of assembly
language code, it creates a line-number entry that maps these lines back to
the original line of C source code that generated them. Each single line-
number entry contains 6 bytes of information. Table A–9 shows the format of
a line-number entry.
Byte
Number Type
0–3
Long integer
4–5
Unsigned
short integer
Figure A–4 shows how line-number entries are grouped into blocks.
As Figure A–4 shows, each entry is divided as follows:
-
For the first line of a function, bytes 0–3 point to the name of a symbol or
a function in the symbol table, and bytes 4–5 contain a 0, which indicates
the beginning of a block.
Description
This entry may have one of two values:
1) If it is the first entry in a block of line-number entries,
it points to a symbol entry in the symbol table.
2) If it is not the first entry in a block, it is the physical ad-
dress of the line indicated by bytes 4–5.
This entry may have one of two values:
1) If this field is 0, this is the first line of a function entry.
2) If this field is not 0, this is the line number of a line in
C source code.
Symbol Index 1
physical address
line number
physical address
line number
Symbol Index n
physical address
line number
physical address
line number
0
0
Advertisement
Chapters
Table of Contents
