Amiga Monitor 1.07 instructions
===============================
The monitor can be started both from CLI and from workbench. If you want
to start the monitor from workbench, you must first make an icon for it.
(starting the monitor from workbench is not recommended, because the
programs that are run under the control of the monitor may require the
CLI environment or else they may wait for workbench startup message
forever...)
Input line editing and command line history:
--------------------------------------------
You can edit the input lines by using the left/right cursor keys to move
left and right, backspace to delete the character before the cursor and
del to delete the character under the cursor. You can use the up/down
cursor keys to get the old command lines (the monitor remembers 10 last
command lines). Shift-cursor-up gets the last command and enters it
automatically (you need not to press <CR>). In assembler mode you can
press Ctrl-E to edit the assembler instruction currently stored in that
address.
Stopping the output:
--------------------
In most cases the output of the monitor can be suspended by pressing SPACE
and continued by pressing SPACE again. To permanently stop the output,
press Ctrl-C.
Numbers:
--------
Hexadecimal numbers can include the '$'-prefix but it is not necessary
when the numbers are positive (or unsigned).
Negative hex numbers must include the '$'-prefix, for example -$12A3.
Positive decimal number must have the '+'-sign, for example +17051.
Numbers can also be represented as ASCII-strings with max. 4 characters,
for example 'HELP' is $48454C50 hex and 'PC' is $00005043 hex.
Note: It is necessary to include the '$' prefix to posivive hex numbers
beginning with 'A' or 'D' in some assembler instructions, because
otherwise they could be interpreted as register names.
Strings:
--------
Strings are used in the fill command, the hunt command, the modify memory
command and the assembler directive dc.b .
Strings are series of bytes, represented by numbers or ASCII-characters
in single quotes or both together separated by commas.
Note: the single quote itself may be included in a quoted string if it
is duplicated.
examples:
'this is a string'
12,34,56
'''' -- this means one single quote
'both',0A,'text',+10,'and','numbers'
New features and bug fixes in version 1.07:
-------------------------------------------
- The disassembler and assembler handle exg Dn,An correctly
(previously the data and address register numbers were reversed)
- The disassembler no more displays any invalid codes as valid
instructions (On the 68000 processor, of course. The monitor does
currently not support 68010/68020 extra instructions).
- The pc-relative indexed addressing mode now works with the assembler.
- Some little bugs were fixed in the assembler.
+ And/or-instructions work with a pc-relative source operand.
+ cmpm works with all sizes
+ most(if not all...) of the bugs that caused the assembler to
assembler invalid instructions have been fixed.
- 'sp' can be used instead of 'a7' in the assembler and the disassmbler
displays a7 as 'sp'.
- The assembler now unserstands blo/bhs, slo/shs and dblo/sbhs
and assembles them as bcs/bcc, scs/scc and dbcs/dbcc
- The disassembler displays address-register relative offsets and short
absolute addresses as signed numbers.
- The monitor works now better with 60-column mode.
- Disk read/write commands can be used with non-chip memory
- Play digisound command has an optional parameter to specify
how many times the sample is played.
- A new command has been added to specify a command line for programs
executed under the control of the monitor.
- Breakpoints work even if you jump into the code at to breakpoint.
The breakpoint does not activate until the instruction at the break
position is executed, so you don't get immediately interrupted.
(internally the monitor uses the trace-exception to skip the breakpoint
at the first time...)
Special Note:
-------------
There is a problem with the walk (trace) command and several instructions
that cause processor exceptions. These instructions are chk, trap #n,
trapv and divu/divs (with divisions by zero). If you try to trace these
instructions, a trace-exception occurs in supervisor-mode, out of the
monitors control and you get a guru meditation alert with number 00000009.
This problem was with the earlier monitor versions as well. In the new
version it can also also occur if you jump to the code at a breakpoint
address, as the monitor internally traces over the breakpoint.
Included with the monitor is a program called patchtrace that changes
directly the processor hardware trace-exception vector to point a new
routine that removes the trap-trace problem.
The following commands are available in the monitor:
----------------------------------------------------
? or the HELP key on the keyboard
displays a help screen.
i -- info
displays info-message
o -- redirect output
usage:
o name -- redirects monitor output to file or device 'name'
o -- returns to normal, output comes to the monitor window
for example, to send the output to printer use 'o PRT:'.
m -- display memory in hex and ASCII
usage:
m -- display 20 lines from current address
m <addr> -- display 20 lines from <addr>
m <addr> <end-addr> -- display from <addr> to <end-addr>
: -- modify memory
usage:
: <addr> <string>
puts the <string> in memory at <addr>
this can also be done with the command 'a <addr> dc.b <string>'
f -- fill memory with a byte or a string of bytes
usage:
f <start-addr> <end-addr> <byte> ;fills with <byte>
f <start-addr> <end-addr> <string> ;fills with the string
example:
f 60000 601FF 4E,71 fills from $60000 to $601FF with NOP-instruction
t -- transfer (move) memory
usage:
t <start-addr> <end-addr> <destination-addr>
the command works correctly even if the source and destination memory
blocks overlap. (if destination is at a higher address than source,
the block is moved backwards, starting at the end)
h -- hunt (find) string in memory
usage:
h <start-addr> <end-addr> <string>
displays all addresses in the range <start-addr>..<end-addr>
where the <string> is found.
c -- compare memory
usage:
c <start-addr> <end-addr> <string>
displays all addresses in the range <start-addr>..<end-addr>
where is corresponding byte in the destination block is different from
the source.
a -- assemble
usage:
a : assemble to the current address
a <addr> : assemble to <addr>
a <addr> <instruction> : assemble <instruction> at <addr>
After assembling an instruction the monitor prompts with the address of
the location following the instruction just assembled and waits a new
instruction to be entered. To exit this mode, simply press <CR> without
entering an instruction. To edit an existing instruction, press Ctrl-E when
the monitor is waiting an assembler instruction.
The assembler understands all the normal 68000 instructions and also
the 'pseudo-instructions' dc.b, dc.w and dc.l, which can be used to
directly put data in memory.
Some notes about using the assembler:
-------------------------------------
When entering assembler instructions which have an implicit size, no
size specifier is allowed in the monitor assembler. These instructions
are for example btst, bchg, bclr, btst, lea, move to/from sr/ccr/usp,
andi/ori/eori #data,sr/ccr Scc (set according to condition),
abcd/sbcd/nbcd and shifts with memory operands.
Instructions that can have different sizes must have the size specifier,
there is no 'default size' (normal assemblers use a default size of word.
the omission of default size is intentional, because it is so easy to
forget the size specifier when you really don't mean the size to be word).
Branch instructions with no size specifier or the .l-specifier assemble
to normal (16-bit offset) branches, if given the .s-size specifier they
assemble to the short form (8-bit offset). The dbxx-(decrement and branch)
-instructions allows no size specifier.
The assembler converts add/sub/and/or/eor with immediate data source
automatically to adda/addi/subi/andi/eori. It does not convert move or
add/sub to the quick form nor does it convert branches automatically to
the short form. You must specify those yourself (so you must use the
moveq/addq/subq- instructions or specify the size .s to branches
as noted above). Also cmp-memory instruction must be entered as cmpm,
the assembler does not convert cmp (an)+,(an)+ to cmpm.
The above conversion rules do not apply to andi/ori/eori with status
register or condition code register. In these cases you must enter the
instruction as andi/ori/eori (don't leave the 'i' out). Also, you
can't enter any size specifier in this case.
d -- disassemble
usage:
d -- disassemble 20 lines from current address
d <addr> -- disassemble 20 lines from <addr>
d <addr> <end-addr> -- disassemble from <addr> to <end-addr>
r -- show or change registers
usage:
r -- displays all registers
r <reg>=<number> or
r <reg> <number> -- puts the value <number> into <reg>
examples:
r D0=0
r A5 $60000
b -- set breakpoints
usage:
b <addr> -- sets a breakpoint to <addr>
Breakpoints are implemented by putting an illegal opcode ($4AFC) in the
breakpoint locations when a G or J command is given. After returning to
the monitor the original contents of the breakpoints are restored. This
means that you can not put breakpoints to ROM (but you can trace ROM code).
br -- remove breakpoints
usage:
br <addr> -- removes the breakpoint at <addr>
br all -- removes all breakpoints
bl -- list breakpoints
usage:
bl -- display a list of all breakpoints
g [addr] -- go (execute machine code)
j [addr] -- jump to subroutine
w [addr] -- walk (single step trace)
the g, j and w-commands use the current program counter value
(displayed with the r-command) if you don't give them an address.
note: there is no easy way to run BCPL programs (CLI commands) or other
programs that use the internal BCPL library from the monitor.
 -- enter command line
usage:
[command line]. If you don't specify a command line (enter only <cr>)
then the monitor will prompt for command line. the command line will
be put in a special memory area and the register a0 will contain pointer
to the string and d0 will contain length of the string (with a linefeed
appended to end of it).
The purpose of this command is to specify a command line for the program
that you are running from the monitor.
l -- load segment
usage:
l <name> -- loads the executable file <name> in memory and displays
the starting address of the first hunk, also sets PC to this address.
only one segment can be loaded at the same time. Before loading a new
segment you must unload the old segment with the u-command. To display
the starting & ending addresses of all the hunks in the file, use the
sl-command.
u -- unload segment
usage:
u -- unload the current segments (frees the memory of that segment)
sl -- segment list
usage:
sl -- displays the starting & ending addresses and length of each hunk
of the currently loaded file.
n -- number base conversion
usage:
n <number> -- displays the <number> in hex, decimal, octal and binary.
If the number is negative, displays it as signed and unsigned.
( -- allocate memory
usage:
( <length> -- allocate <length> bytes any type of memory
( <length> 'CHIP' -- allocate <length> bytes of chip memory
Displays the start & end addresses of the allocated memory block.
& -- allocate absolute memory location
usage:
& <addr> <length> -- allocate <length> bytes at <addr>
) -- free memory
usage:
) <addr> -- frees the memory block starting at <addr>
) all -- frees all the memory allocated with the (- and &-commands
sm -- show allocated memory
usage:
sm -- display all memory blocks allocated with the (- and &-commands
[ -- read file
usage:
[ <addr> <name> -- reads the file <name> to memory starting at <addr>
] -- write file
usage:
] <addr> <length> <name> -- creates a file named <name> and writes <length>
bytes of memory starting at <addr> to the file.
< -- read disk sectors
usage:
< <addr> <drive> <start-sector> <number-of-sectors>
Reads <number-of-sectors> sectors from the disk in unit <drive> to memory
starting at <addr>. <drive> is a number between 0..3,
corresponding the DOS devices DF0: -- DF3:
In this version the read destination address
does not need to be in chip memory.
> -- write disk sectors
usage:
> <addr> <drive> <start-sector> <number-of-sectors>
Writes <number-of-sectors> sectors to the disk in unit <drive> from memory
starting at <addr>. <drive> is a number between 0..3,
corresponding the DOS devices DF0: -- DF3:
In this version the write source address
does not need to be in chip memory.
= -- corrects a disk block checksum
usage:
= <addr> -- if there is a DOS-format disk block read into memory at <addr>,
calculates the correct checksum for the block and stores it in the block.
Displays old and new checksums. This command is useful if use use the
monitor as a disk editor.
# -- corrects bootblock checksum
usage:
# <addr> -- if there is a disk bootblock (2 disk blocks, 1024 bytes) read
into memory at <addr>, calculates a new checksum for the bootblock and stores
it in the bootblock. Displays old and new checksums.
! -- play digisound
usage:
! <addr> <length> <period> [<count>]
Plays sound <length> bytes starting at <addr> and using sampling period
<period>. the sound repeats <count> times or until you stop it by
pressing Ctrl-C. <addr> must be in CHIP memory!.
cls -- clears the monitor window
del <filename> -- deletes a file
cd <dirname> -- sets the current directory
dir [<name>] -- displays the directory
\ -- new CLI
Opens a new CLI window. This CLI is a separate process, so you can continue
to use the monitor when the CLI window is there. Also the CLI window does
not close automatically when you exit the monitor. You must close it with
the CLI command EndCLI. In fact the monitor uses the NewCLI command
to open the new CLI window.
x -- exit
frees all memory allocated by the monitor, closes redirection file (if open)
and exits the monitor.
version 1.07 of the monitor (and this document) by Timo Rossi 1989-08-28
* Note from John van Dijk (Who put this in Public Domain)
I would like to thank Timo for hearing my critisism and removing the bugs
I found in a record time, it proves that feedback to the programmer can
be very helpful for both the user and the programmer to make a better
product. The reason why I like this monitor so much is it's size, the
complete multitasking (by using a seperate window) and the vast number
of handy options. Timo asked me to make sure that the PATCHTRACE program
was included too. And for installing ROSSIMON V1.07 on your disk is a
ZOO file also available. Have 'fun' with your debugging.
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