Drawing data values with the eutodraw system

Drawing data values with the eutodraw system.

William Overington

As these documents have progressed, the eutodraw system has been gradually extended. Action codes 31, 32, 33, 34 and 35 have been gradually introduced to draw data as follows.

31 Draw the contents of ad1456 as a double.
32 Draw the contents of ai1456 as an integer.
33 Draw the contents of ac1456 as a character.
34 Draw the contents of ad1456 as a string.
35 Draw the contents of ai1456 as if a Boolean variable.

These action codes are indeed useful and continue to be part of the system. In addition five new action codes, action codes 41 through to 45, are introduced which correspond as far as the type of data drawn to action codes 31 through to 35.

41 Draw the contents of a designated element of md1456 as a double.
42 Draw the contents of a designated element of mi1456 as an integer.
43 Draw the contents of a designated element of mc1456 as a character.
44 Draw the contents of a designated element of md1456 as a string.
45 Draw the contents of a designated element of mi1456 as if a Boolean variable.

However, these new action codes get their data not from the a register but from a memory element. Unlike the action codes 31 through to 35, which each use one column of the eutodraw table, action codes 41 through to 45 each use two columns of the eutodraw table. The second column is used to identify which particular memory element, of the type signaled by the action code, is to be used as the source of the data. The x row of that column of the eutodraw table is used to carry this index number. It is termed the eutomemoryindex value. The y row of that column of the eutodraw table is conventionally set to zero. The contents of the memory element is unaltered.

Here is an example, for drawing the character that is in mc1456[17] at the point x = 200, y = 300 in blue, remembering that blue is colour 6. Please note that the data used is that in mc1456[17] when the $E command is obeyed.

x

200

17

y

300

0

c

4306

-2

The result is indistinguishable on the screen as to whether the item of data were obtained from the a register or from a memory element.

1456 object code

31	Draw the contents of ad1456 as a double.
32	Draw the contents of ai1456 as an integer.
33	Draw the contents of ac1456 as a character.
34	Draw the contents of ad1456 as a string.
35	Draw the contents of ai1456 as if a Boolean variable.

41	Draw the contents of a designated element of md1456 as a double.
42	Draw the contents of a designated element of mi1456 as an integer.
43	Draw the contents of a designated element of mc1456 as a character.
44	Draw the contents of a designated element of md1456 as a string.
45	Draw the contents of a designated element of mi1456 as if a Boolean variable.