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.

a

Display arguments

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.

b

AAAA BB
Tabulate memory in double byte format

Tabulate the contents of memory in double byte, four digit values.

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 start.

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.

c

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