/*
  Copyright 2004 Ronald S. Burkey <info@sandroid.org>

  This file is part of yaAGC. 

  yaAGC is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  yaAGC is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with yaAGC; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  Filename:     Parse2CADR.c
  Purpose:      Assembles the 2CADR and 2BCADR pseudo-ops.
  History:      07/09/04 RSB.   Adapted from 2FCADR.
                2012-10-02 JL   Added note.
                2012-10-04 JL   Move FixSuperbankBits to Utilities.c.
                2017-06-17 MAS  Refactored superbank bit logic.
 */

#include "yaYUL.h"
#include <stdlib.h>
#include <math.h>
#include <string.h>

/* (JL, 2012-10-02)
 *
 * NOTE: 2FCADR is not used by any of the actual flight software sources we currently have.
 * 2CADR is used instead.
 */

//-------------------------------------------------------------------------
// Returns non-zero on unrecoverable error.
int Parse2CADR(ParseInput_t *InRecord, ParseOutput_t *OutRecord)
{
    Address_t Address;
    int i;

    IncPc(&InRecord->ProgramCounter, 2, &OutRecord->ProgramCounter);
    if (!OutRecord->ProgramCounter.Invalid && OutRecord->ProgramCounter.Overflow) {
        strcpy(OutRecord->ErrorMessage, "Next code may overflow storage.");
        OutRecord->Warning = 1;
    }

    OutRecord->EBank = InRecord->EBank;
    OutRecord->SBank = InRecord->SBank;
    OutRecord->NumWords = 2;
    OutRecord->Words[0] = 0;
    OutRecord->Words[1] = 0;

    if (InRecord->Extend && !InRecord->IndexValid) {
        strcpy(OutRecord->ErrorMessage, "Illegally preceded by EXTEND.");
        OutRecord->Fatal = 1;
        OutRecord->Extend = 0;
    }

    if (InRecord->IndexValid) {
        strcpy(OutRecord->ErrorMessage, "Illegally preceded by INDEX.");
        OutRecord->Fatal = 1;
        OutRecord->IndexValid = 0;
    }

    i = FetchSymbolPlusOffset(&InRecord->ProgramCounter, InRecord->Operand, InRecord->Mod1, &Address);
    if (i) {
        sprintf(OutRecord->ErrorMessage, "Symbol \"%s\" undefined or offset bad", InRecord->Operand);
        OutRecord->Fatal = 1;
    } else {
        if (Address.Invalid) {
            strcpy(OutRecord->ErrorMessage, "Destination address not resolved.");
            OutRecord->Fatal = 1;
            return (0);
        }

        if (!Address.Address) {
            strcpy(OutRecord->ErrorMessage, "Destination is not a memory address.");
            OutRecord->Fatal = 1;
            return (0);
        }

        OutRecord->Words[0] = Address.SReg;

        if (InRecord->EBank.current.SReg >= 0 && InRecord->EBank.current.SReg < 01400)
            OutRecord->Words[1] = InRecord->EBank.current.SReg / 0400;
        else
            OutRecord->Words[1] = InRecord->EBank.current.EB;

        if (Address.SReg < 02000)
            ;
        else if (Address.SReg <= 07777) {
            if (Address.SReg < 04000)
                OutRecord->Words[1] |= (Address.FB << 10);
            else
                OutRecord->Words[1] |= ((Address.SReg / 02000) << 10);
        } else {
            strcpy(OutRecord->ErrorMessage, "Internal error implementing 2CADR.");
            OutRecord->Fatal = 1;
            return (0);
        }

        if (Address.FB >= 030 && Address.FB <= 037) {
            // Determine the superbank needed for the target address
            unsigned AddressSBank;
            if (Address.Super)
                AddressSBank = 4;
            else
                AddressSBank = 3;

            OutRecord->Words[1] |= AddressSBank << 4;

            // Generate a warning if we're implicitly referencing a different superbank.
            // ... someday? It really looks like there are things that YUL would have cussed
            // in, e.g., Luminary 210, but GAP does not appear to have done so. For now
            // we will just let it slide...

            //if (InRecord->ProgramCounter.FB >= 030 && InRecord->ProgramCounter.FB <= 037
            //   && AddressSBank != InRecord->SBank.current) {
            //    sprintf(OutRecord->ErrorMessage, 
            //            "2CADR referencing unestablished superbank %u when in superbank %u", 
            //            AddressSBank, InRecord->SBank.current);
            //    OutRecord->Warning = 1;
            //}

        } else if (!EarlySBank) {
            // If the target address is not in a superbank, then simply fill in the
            // superbank bits with whatever the established superbank is...
            // *unless* we're building with pre-1967 superbank behavior.
            OutRecord->Words[1] |= InRecord->SBank.current << 4;
        }
    }

#ifdef YAYUL_TRACE
    PrintTrace(InRecord, OutRecord);
#endif

    return (0);
}