Hardware Reference
In-Depth Information
Command
Meaning
Function
Load
Loads the file previously specified by the Name
(N)
command. The
file specification is held at address CS:0080. If no load address is specified,
the file is loaded from address CS:0100.
L [addr]
Move
Moves (replicates) memory in the given range so that it is replicated
starting at the specified address.
M range addr
Name
Names a file to be used for a subsequent Load
(L)
or Write
(W)
command.
Example:
NA:
\
MYPROG.COM
names the file MYPROG.COM stored in the root directory of drive A:
for a subsequent load or write command.
N filespec
Port output
Output a given byte value to the specified I/O port address.
O port
Example:
O 303 FE
outputs a byte value of FE from I/O port address 303.
byte
Proceed
Executes a subroutine, interrupt loop or string operation and resumes
control at the next instruction. Execution starts at the specified address and
continues for the specified number of instructions. If no address is
specified, execution commences at the address given by CS:IP.
P [=addr] [instr]
Quit
Exits debug and return control to the current MS-DOS shell.
Q
Register
Displays the contents of the specified register and allows the contents
to be modified. If a name is not specified, the contents of all of the CPU
registers (including flags) is displayed together with the next instruction to
be executed (in hexadecimal and in mnemonic format).
R [regname]
Search
Search memory within the specified range for the listed data bytes.
S range
Example:
S 0100 0800 20,1B
searches memory between address DS:0100 and DS:0800 for
consecutive data values of 20 and 1B.
list
T [=addr] [instr]
Trace
Traces the execution of a program from the specified address and executing
the given number of instructions. If no address is specified, the execution
starts at address CS:IP. If the number of instructions is not specified then
only a single instruction is executed. A register dump (together with a
disassembly of the next instruction to be executed) is displayed at each step.
Examples:
T
traces the execution of the single instruction referenced by CS:IP.
T =200,4
traces the execution of four instructions commencing at address CS:0200.
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continued
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