[comp.unix.sysv386] Unprotecting I/O above 10 bits

lamb@saddle.UUCP (Richard Lamb) (12/15/90)

	I wanna do "outb(0x3000,0xff)". How do I do this under SCO or
any other 386 unix from a user program. 
I have routines that go into the GDT, then TSS I/O bitmaps to clear out
protection on 0x000 to 0x3ff but thats it (the I/O bitmap only covers
that range).
				Thanx
					Rick

############################################################################
#  _  /|     | Richard Lamb                  Internet: lamb@lids.mit.edu   #
#  \'o.O'    | MCI Mail: 423-9516            Telex: 6504239516             #
#  =(___)=   | SnailNet: |XtcN Ltd         |    |XtcN Ltd                 |#
#     U      |           |16 Cochituate St.| OR |4425 Butterworth Pl. N.W.|#
# Ack! Phht! |           |Natick MA 01760  |    |Washington D.C. 20016    |#
#            |           |Voice:5086552960 |    |Voice:2023633661         |#
############################################################################
-- 
############################################################################
#  _  /|     | Richard Lamb                  Internet: lamb@lids.mit.edu   #
#  \'o.O'    | MCI Mail: 423-9516            Telex: 6504239516             #
#  =(___)=   | SnailNet: |XtcN Ltd         |    |XtcN Ltd                 |#
#     U      |           |16 Cochituate St.| OR |4425 Butterworth Pl. N.W.|#
# Ack! Phht! |           |Natick MA 01760  |    |Washington D.C. 20016    |#
#            |           |Voice:5086552960 |    |Voice:2023633661         |#
############################################################################

waltc@cpqhou.uucp (Walt Croom) (12/18/90)

> 	I wanna do "outb(0x3000,0xff)". How do I do this under SCO or
> any other 386 unix from a user program. 
> I have routines that go into the GDT, then TSS I/O bitmaps to clear out
> protection on 0x000 to 0x3ff but thats it (the I/O bitmap only covers
> that range).
> 				Thanx
> 					Rick

Do the following before your outb to write to any I/O address:

  #define SI86V86 71
  #define V86SC_IOPL 4

  sysi86(SI86V86, V86SC_IOPL, 0x3000);        /* must be root */

--
Walt Croom               ..!uunet!cpqhou!waltc
Compaq Computer Corp.    voice: 713-374-6027
20555 SH249, M040602     fax: 713-374-7769
Houston, TX  77070