System information

Section 4
CP/M Dynamic Debugging Tool
4.1 Introduction
The DDT program allows dynamic interactive testing and debugging of programs generated in
the CP/M environment. Invoke the debugger with a command of one of the following forms:
DDT
DDT filename.HEX
DDT filename.COM
where filename is the name of the program to be loaded and tested. In both cases, the DDT
program is brought into main memory in place of the Console Command Processor (CCP) and
resides directly below the Basic Disk Operating System (BDOS) portion of CP/M. Refer to
Section 5 for standard memory organization. The BDOS starting address, located in the address
field of the JMP instruction at location 5H, is altered to reflect the reduced Transient Program
Area (TPA) size.
The second and third forms of the DDT command perform the same actions as the first, except
there is a subsequent automatic load of the specified HEX or COM file. The action is identical to
the following sequence of commands:
DDT
Ifilename.HEX or Ifilename.COM
R
where the I and R commands set up and read the specified program to test. See the explanation of
the I and R commands below for exact details.
Upon initiation, DDT prints a sign-on message in the form:
DDT VER m.m
where m.m is the revision number.
3.7 A Sample Session CP/M Operating System Manual
4-1