Intel XENIX 286 Programmers Guide (86) - Tenox.tc

XENIX Programming adb: Program Debugger
Decimal, Octal, and Hexadecimal Integers
Decimal integers must begin with a nonzero decimal digit. Octal numbers must begin
with a zero and may have octal digits only. Hexadecimal numbers must begin with the
prefix "Ox" and may contain decimal digits and the letters "a" through "f" {in both
uppercase and lowercase). The following are valid numbers:
Decimal
34
4090
Octal
042
07772
Hexadecimal
Ox22
Oxffa
Although decimal numbers are displayed with a trailing decimal point (.), you must not
use the decimal point when typing the number.
Symbols
Symbols are the names of global variables and functions defined within the program
being debugged and are equal to the address of the given variable or function. Symbols
are stored in the program's symbol table and are available if the symbol table has not
been stripped from the program file (see strip in Appendix B, "Programming
Commands").
In expressions, you may spell the symbol exactly as it is in the source program or as it
has been stored in the symbol table. Symbols in the symbol table are no more than eight
characters long, and those defined in C programs are given a leading underscore ( -).
The following are examples of symbols:
main main hex2bin out of
Note that if the spelling of any two symbols is the same (except for a leading
underscore), adb will ignore one of the symbols and allow references only to the other.
For example, if both "main" and "_main" exist in a program, then adb accesses only the
first to appear in the source and ignores the other.
When you use the ? command, adb uses the symbols found in the symbol table of the
program file to create symbolic addresses. Thus, the command sometimes gives a
function name when it displays data. This does not happen if the ? command is used for
text (instructions) and the I command for data. Local variables cannot be addressed.
6-5