DRL T.PAGE (octal 104) - set pagination options.

Usage:

drl    t.page
zero   buff,0

Where:

buff: is a pointer to a three-word buffer that is copied directly into the UST's pagination control words.

Description:

The three pagination control words at offset .LPAGE in the UST are used by the system to determine when to pause terminal output. The upper half of the first word contains the page length; the lower half contains the current line count (maintained by the system). If this word is zero, the pagination is turned off completely.

The next two words consist of a sequence of eight 9-bit bytes, each one defining one pagination character. Each of these bytes contains two fields.

The lower seven bits determine the pagination character.

The upper two bits determine the action taken by the system when the specified character is put out. These bits have the following meaning.

0 - The character is a linefeed character.
1 - The character is a pause character.
2 - The character is a reverse linefeed character.
3 - The character is a formfeed character.

When the system outputs a character designated as a linefeed character, the current line count (the lower half of pagination word 0) is incremented. If this count is greater than the page length, the terminal output pauses before putting out the character. The current count is then set to zero.

When the system outputs a formfeed character, the output pauses before putting the character out, provided the current line count is non-zero. If the current line count is zero, the character is put out without pausing. If the output pauses, the current line count is set to zero. Thus, several formfeeds in a row only cause one pause, since the current line count is zero for subsequent formfeeds.

When the system outputs a reverse line feed, the current line count is decremented by one if it was originally non-zero.

When the system puts out a pause character, the output pauses just after sending the character. The current line count is then set to zero.

Examples:

       drl     t.page
       zero    poff,0
.
poff   zero
       bss     2       these words are irrelevant

This turns off pagination, by setting the first pagination control word to zero.

lfchar equ     0       type for linefeed char
ffchar equ     3       type for formfeed char
.
       drl     t.page
       zero    normal,0
.
normal zero    20,0    page length of 20,
       vfd     2o/lfchar,7o/012,2o/ffchar,7o/014
       zero

This sets a page length of 20, using the ASCII line feed as a linefeed character and the ASCII formfeed character as a formfeed character.

Bugs:

The append characters provided for a DRL KOUT, DRL KOUTN, or DRL KOTNOW are ignored by the system when it is checking for the pagination characters.