Commodore PC - Trace

236 MS-DOS User's Reference
(T)race
Using the Trace
command
Trace
Purpose:
Executes one instruction and displays the contents of all registers,
flags, and the decoded instruction.
Syntax:
T[ = address] [value]
Comments:
If you include the = address option in the T (trace) command,
tracing occurs at the specified = address. The value option causes
debug to execute and trace the number of steps specified by
value.
The T command uses the hardware trace mode of the 8086 or
8088 microprocessor. Consequently, you may also trace instruc
tions stored in ROM (Read Only Memory).
Example:
Suppose you type the following command:
U
u
u
In response, debug would return a display of the registers, flags,
and decoded instruction for that one instruction. Assuming, for
this example, that the current position is 04BA:011A, debug
might return the following display:
AX=OEOO BX=OOFF CX=0007 DX=01FF SP=039D BP=OOOO
SI=005C DI=0000 DS=04BA ES=04BA SS=O4BA CS=04BA
IP=011A NV UP DI NG NZ AC PE NC
04BA:011A CD21 INT 21
If you type the following command, debug executes sixteen (10
hex) instructions beginning at Oil A in the current segment, and
then displays all registers and flags for each instruction as it is
executed. The display scrolls away until the last instruction is exe
cuted, and then stops. Now you can see the register and flag
values for the last few instructions performed:
T=011A 10
Remember that if you want to study the registers and flags for any
instruction (at any time), you can press controls to stop the
display from scrolling.
U
u
u
u