Computer and Software Support


Debug: T (Trace)

This page is from Microsoft

Page updated January 21, 2005

 

Executes one instruction and displays the contents of all registers, the status of all flags, and the decoded form of the instruction that is executed. Used without parameters, t begins tracing at the address specified by your program's CS:IP registers.
 
 
Syntax
t [=Address] [Number]
Parameters
Address
Specifies the address at which Debug.exe is to start tracing instructions.
Number
Specifies the number of instructions to be traced. This value must be a hexadecimal number. The default value is 1.
?
Displays a list of debug subcommands.
Remarks
  • Windows XP and the Windows Server 2003 family of products do not use this command. It is included only to preserve compatibility with existing MS-DOS files, but it has no effect at the command line because the functionality is automatic.
  • Specifying valid Address entries

    Address is a two-part designation, containing either an alphabetic segment register or a four-digit segment address with an offset value. You can omit the segment register or segment address. CS is the default segment for the following debug subcommands: a, g, l, t, u, and w. DS is the default segment for all other subcommands. All numeric values are in hexadecimal format. You must include a colon between the segment name and the offset value. The following are valid addresses:

    CS:0100

    04BA:0100

  • Tracing instructions in read-only memory

    The t subcommand uses the hardware trace mode of the 8086 or 8088 microprocessor. Therefore, you can also trace instructions stored in read-only memory (ROM).

  • For information about executing a loop, a repeated string instruction, a software interrupt, or a subroutine by using the p (proceed) subcommand, see Related Topics.
  • For information about executing the program currently in memory by using the g (go) subcommand, see Related Topics.
Examples
If the position of the instruction in the program is 04BA:011A, Debug.exe displays the following information:

AX=0E00 BX=00FF CX=0007 DX=01FF SP=039D BP=0000 SI=005C DI=0000

DS=04BA ES=04BA SS=04BA CS=O4BA IP=011A NV UP DI NG NZ AC PE NC

04BA:011A CD21 INT 21

Formatting legend

Format Meaning
Italic Information that the user must supply
Bold Elements that the user must type exactly as shown
Ellipsis (...) Parameter that can be repeated several times in a command line
Between brackets ([]) Optional items
Between braces ({}); choices separated by pipe (|). Example: {even|odd} Set of choices from which the user must choose only one
Courier font Code or program output

Some of these terms may be the same or similar to DOS commands. For information on DOS Commands, click here