Silicon Graphics IRIS Series Terminal Manual page 71

IRIS TERMINAL GUIDE 67
Appendix F
system call. has the opposite effect.
setslowcom()
Both of these routines (and others) call the routine that sends 50
netinit()
nulls to the terminal. 50 nulls is longer than any possible graphical transaction,
so no matter what state the terminal was in, this will make sure that it is put in
terminal mode. (If it was in graphics mode, half-finished with an array
transmission, this will cause an error and force the IRIS into terminal mode.)
is the routine that is called to send a character to the IRIS. In the
putgchar()
attached example, it implements a simple buffer that guarantees that any
graphics command will not be broken across a buffer boundary. Thus, at the
end of each buffer transmission, the IRIS will be in terminal mode.
flushg()
is an internal routine to flush the host buffers out to the IRIS.
F.4 Special IRIS Graphics Library Commands
The five routines , , , , and should
ginit() gexit() greset() gfinish() gflush()
be implemented as shown in the included example. The automatically
generated graphics stubs include calls to and .
xginit() xgreset()
F.5 Echo Control
The routines and should make the operating system
echoff() echon()
dependent calls to turn off or on local echoing so that when the IRIS is sending
information back to the host, the host will not try to echo it. This may not be
necessary for operating systems that provide a non-echoing read.
F.6 Floating Point Number Conversion
The routines and convert from the IEEE floating point
IEEE2F() F2IEEE()
format to the host's internal floating point format, and vice-versa.
F.7 Data Transmission Routines
The remainder of the communications routines simply transmit and receive
data. In order to accommodate different hosts, all data is assumed to be sent
in the IRIS format. The IRIS has a 68000 or 68010 with its own peculiar byte
orderings.
F.8 IRIS Memory Organization
Suppose that the four hexadecimal values 0x00, 0x01, 0x02, and 0x03 are stored
in the IRIS in such a way that 0x00 is stored in byte 0, 0x01 in byte 1, and so
on. If we read address 0 as a word (16 bits), the IRIS will see the value 0x0001.
The word at address 2 is 0x0203. The long word (32 bits) at address 0 is
0x00010203. (On a DEC-11 machine, for example, the words at 0 and 2 would
be 0x0100 and 0x0302, and the long at address 0 would be 0x03020100.)
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