SYE-EX – A 1K extension program for NAS-SYS monitors – Part 2
by David G. Johnson
In the last part we described in outline, most of the
features of a 1K extension to NAS-SYS. The monitor extension
itself will be printed in full in a later issue. For now, we
will continue with a detailed description of the additional
keyboard commands provided by SYS-EX.
Display the contents of the arguments (ARG1 through
ARG10) in the NAS-SYS workspace.
Each argument is displayed as a four digit hexadecimal
number. Arguments 1 through 8 are displayed on the first line
following the command letter and arguments 9 and 10 are
displayed on the second line following the command letter.
Tabulate memory in double byte format
Tabulate the contents of memory in double byte, four
The contents of any specified portion of memory are
displayed. Each pair of consecutive bytes is treated as
representing a four digit hexadecimal number. The format of
the display is similar to that used in the ‘a’ command, with 8
four digit numbers displayed on each line.
AAAA – memory address at which the tabulation is to
BB – Length of required tabulation. (i.e. the number of
double byte values). If more than two digits are entered,
only the final two are used.
The ‘a’ and the ‘b’ commands share common processing which
relies heavily on the NAS-SYS routine TBCD3.
AAAA BBBB CCCC
Swap the contents of two specified areas of memory
The values which are present in two specified portions
of memory are exchanged.
This command is similar to the NAS-SYS ‘C’ (Copy)
command in that the arguments used define the same values.
However, instead of the ‘source’ area just overwriting the
‘target’ area, the source is moved to the target and the
target is simultaneously moved to the source.
The start address of each portion of memory and the
length of memory to be exchanged are supplied with the
command. Providing that the two specified portions of memory
do not overlap, the operation of the command is