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EPOS

Experimental Protected-mode Operating System

ports.h
/*
EPOS
http://www.atanaslaskov.com/epos/

FILE:        ports.h
DESCRIPTION: Hardware port services (for use by device drivers)

NOTE: Currently this module implements only single byte get and put
methods for port access. This is rather unefficient, having in mind
that each system call involves switching between user mode
and supervisor mode.
 
BSD LICENSE
Copyright (c) 2006, Atanas Laskov
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
   1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL ATANAS LASKOV BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


// Defines
//
#define PHANDLE unsigned long
#define PSTATE  unsigned char

#define P_ST_OK        0
#define P_ST_OUTOFRES  1
#define P_ST_INVPARAM  2

#define P_MAX_AREA_CNT_PER_PROCESS 10

// Data structures
//
struct PArea{
    unsigned short wStart;
    unsigned short wEnd;
    PHANDLE hAreahandle;
    PSTATE  st;
};

struct PHandle{
    PHANDLE hAreahandle;
    PSTATE  st;
};

struct PTransfer{
    PHANDLE hAreahandle;
    unsigned short wOfs;
    unsigned char bByte;
    PSTATE st;
};

// Kernel internals
//
void k_portInit();
void k_portClearMaskOf(PID dwPID);
void k_portSetMaskFor(PID dwPID);

// User services
//
void pLockPorts(struct PArea *p);
void pFreePorts(struct PHandle *p);
void pPutb(struct PTransfer *p);
void pGetb(struct PTransfer *p);