2.2 The IBM 7171 ASCII Device Attachment Control Unit - Index of

These output strings are called Control Sequence Strings (CSS). They are specificto each terminal and must be found in the terminal manufacturer's specificationmanual. There are 19 defined Control Sequence Strings, but CSSs 7 and 8 are notused.Following is a list of each of the CSSs and their meanings:1. Reposition is required to generate the terminal specific control charactersequence to position the cursor. When it is received by the terminal, the cursoris positioned according to the data sent in the string. As such some charactersor character strings in this control string are variable and must be dynamicallygenerated using the current cursor position. The dynamic generation of cursorposition is performed by the routines shown in the following figure:X'FE'X'FC'X'FA'X'F8'X'F6'X'F4'X'FO'BINXBINYCHARXCHARYUSERXUSERYHARDCOPYBinary column valueBinary row valueCharacter column valueCharacter row valueUser generated column valueUser generated row valueHardcopy terminal positioningFigure 4-2. Cursor Positioning Routine Namesa. The two routines BINX and BINY each form a one byte binary position byadding the cursor base value to the column or row number. This is themost common cursor positioning method. The following table gives thehex values generated by BINX and BINY for different possible cursor basevalues.row/column Base = X'0020' Base = X'OOOO' Base = X'0001'(decimal) HEX ANSI HEX ANSI HEX ANSI0 20 2/0 00 0/0 01 0/11 21 2/1 01 0/1 02 0/22 22 2/2 02 0/2 03 0/316 30 3/0 10 1/0 11 1/123 37 3/7 17 1/7 18 1/833 41 4/1 21 2/1 22 2/279 6F 6/15 4F 4/15 50 5/0b. The ANSI X3.64 standard for terminal control sequences defines insteadthe use of character text strings for numeric values. In this scheme, column20 would be represented in the proper control string context by the ASCIIcharacter string "20" (X' 3230'). The two routines CHARX andCHARY will produce such numeric character parameters for terminals thatconform to this convention. When this form of addressing is used, thecursor base should be specified as the number (not the character) zero orone. The following table gives the hex values generated by CHARX andCHARY for different possible cursor base values.4-12 IBM 7171 Reference Manual and Programming Guide