pif.c

/*
 * Project 64 - A Nintendo 64 emulator.
 *
 * (c) Copyright 2001 zilmar (zilmar@emulation64.com) and
 * Jabo (jabo@emulation64.com).
 *
 * pj64 homepage: www.pj64.net
 *
 * Permission to use, copy, modify and distribute Project64 in both binary and
 * source form, for non-commercial purposes, is hereby granted without fee,
 * providing that this license information and copyright notice appear with
 * all copies and any derived work.
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event shall the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Project64 is freeware for PERSONAL USE only. Commercial users should
 * seek permission of the copyright holders first. Commercial use includes
 * charging money for Project64 or software derived from Project64.
 *
 * The copyright holders request that bug fixes and improvements to the code
 * should be forwarded to them so if they want them.
 *
 */
#include <stdint.h>

// Skeletal support so USFs that read the controller won't fail (bad practice, though)

void ProcessControllerCommand ( int32_t Control, uint8_t * Command);

uint8_t *PIF_Ram = 0;

void PifRamRead (void)
{
    int32_t Channel, CurPos;

    Channel = 0;
    CurPos  = 0;

    for(CurPos = 0; CurPos < 0x40; CurPos++)
    {
        switch(PIF_Ram[CurPos])
        {
        case 0x00:
            Channel += 1;
            if (Channel > 6)
            {
                CurPos = 0x40;
            }
            break;
        case 0xFE:
            CurPos = 0x40;
            break;
        case 0xFF:
            break;
        case 0xB4:
        case 0x56:
        case 0xB8:
            break; /* ??? */
        default:
            if ((PIF_Ram[CurPos] & 0xC0) == 0)
            {
                CurPos += PIF_Ram[CurPos] + (PIF_Ram[CurPos + 1] & 0x3F) + 1;
                Channel += 1;
            }
            else
            {
                CurPos = 0x40;
            }
            break;
        }
    }
}

void PifRamWrite (void)
{
    int Channel, CurPos;

    Channel = 0;

    for (CurPos = 0; CurPos < 0x40; CurPos++)
    {
        switch(PIF_Ram[CurPos])
        {
        case 0x00:
            Channel += 1;
            if (Channel > 6)
            {
                CurPos = 0x40;
            }
            break;
        case 0xFE:
            CurPos = 0x40;
            break;
        case 0xFF:
            break;
        case 0xB4:
        case 0x56:
        case 0xB8:
            break; /* ??? */
        default:
            if ((PIF_Ram[CurPos] & 0xC0) == 0)
            {
                if (Channel < 4)
                {
                    ProcessControllerCommand(Channel,&PIF_Ram[CurPos]);
                }
                CurPos += PIF_Ram[CurPos] + (PIF_Ram[CurPos + 1] & 0x3F) + 1;
                Channel += 1;
            }
            else
            {
                CurPos = 0x40;
            }

            break;
        }
    }
    PIF_Ram[0x3F] = 0;
}

// always return failure
void ProcessControllerCommand ( int32_t Control, uint8_t * Command)
{
    Command[1] |= 0x80;
}