Other options in brief:
- Disassemble a program which is not at its normal execution address.
- Change lines per page and page size.
- Display the output from only part of a disassembly of a large program
- NAS-DIS incorporates a subroutine called REVAS (!) which you could
call from your own program.
- Good validation of user input when selecting options.
We have tested NAS-DIS and can verify that it disassembles all
machine code correctly, with no nasty quirks. It is an excellent piece
NAS-DIS is available from Nascom through your dealers. Ask your
dealer about it. If he doesn’t know anything about it, nag Nascom Sales
Department for prices and ask them why it isn’t available.
SUPER DEBUG (we’ll call D-BUG) is a 1K program which runs under
NAS-SYS. In order to work, it requires that NAS-DIS also be installed.
D-BUG lives at C000H – C3FFH, D-BUG can therefore fill the eighth 2708
socket on the Nascom 2 CPU board, so that with NAS-DIS the whole
becomes a 4K package.
The aim of D-BUG is to make it easier to examine the workings
of other programs. The principle feature is a comprehensive and
labelled display of all the CPU registers, as well as the eight bytes
pointed to by each of the main registers. The example below gives an
idea of the display:
As you can see, the next instruction to be executed has also been
disassembled. This means that you can single step through a program and
read each instruction in assembler at the same time. This also works
D-BUG uses NAS-SYS editing in an unusual and advanced way. The
cursor can be moved up and the lines of display edited, one line at a
time. The memory locations pointed at by the registers can be altered,
and the values of SP, IX, IY, HL, DE, BC, AF, and PC can also be
altered. If the code after PC is altered, the disassembled source code
appears at once. The values of IFF2, I, and the alternate registers
cannot be directly altered in this way. A character representation of
the flags is output when the flags are set, and these can be altered by
editing the F register.