Revision 2 == The original upload contained an error. The documents are
dated October 13. Sorry for the double upload!!!

October 14, 1986

The purpose of these routines is to provide improved communcation support
for the INS8250 chip on the IBM PC and compatible. These routines were
originally conceived to provide high speed ring buffered i/o between a
microvax and an IBM PC, primarily to support Kermit protocol in a non-
unix environment. The routine asyturbo.pas/.inc is designed as an ed-
ucational tool to show people how to program an 8250 and support all int-
errupt modes. None of the routines currently available in the Borland SIG
support all interrupt modes, while providing ring buffered input AND output.
These routines have also been useful supporting an HP laser printer, where
gobs of data transfer are necessary. You will find that buffered output will
significantly speed up your programs. Programs like ITERM can be speeded up
by as much as 30% when uploading a file, provided that a sufficiently large
buffer is allocated. The program asyinlin.pas/.inc is built only for speed.
The assmebler source is provided, but it may not be inherently obvious as to
the program logic.

To compile the programs, either compile asyinlin.pas or asyturbo.pas. There
is a short screen that tells you to hit escape to exit. The program will
dump lots of interrupt statistics at you at the end. These are not necessary
but will help me provide you with debugging info if it is needed. The only
odd characteristics of the programs are that the modem MUST be on when
initially run. The modem can be turned off and back on during operation.
The bug is because of the way I don't handle the data bits. The next
revision will fix the problem by providing a check for delta bits.

Gene Harris
72067,321

October 14, 1986

All bugs have been fixed, and you can turn on your modem anytime you feel
like it. Also, several minor improvements concerning the way the write
interrupts were handled have been made.