dolphin/Source/Plugins/Plugin_DSP_HLE/Src/UCodes/UCode_GBA.cpp

// Copyright (C) 2003 Dolphin Project.

// This program 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, version 2.0.

// This program 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 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#include "../Globals.h"
#include "../DSPHandler.h"
#include "UCodes.h"
#include "UCode_GBA.h"

CUCode_GBA::CUCode_GBA(CMailHandler& _rMailHandler)
: IUCode(_rMailHandler)
{
	m_rMailHandler.PushMail(DSP_INIT);
}

CUCode_GBA::~CUCode_GBA()
{
	m_rMailHandler.Clear();
}

void CUCode_GBA::Update(int cycles)
{
	// check if we have to send something
	if (!m_rMailHandler.IsEmpty())
	{
		g_dspInitialize.pGenerateDSPInterrupt();
	}
}

void CUCode_GBA::HandleMail(u32 _uMail)
{
	static bool nextmail_is_mramaddr = false;
	static bool calc_done = false;

	if (m_UploadSetupInProgress)
	{
		PrepareBootUCode(_uMail);
	}
	else if ((_uMail >> 16 == 0xabba) && !nextmail_is_mramaddr)
	{
		nextmail_is_mramaddr = true;
	}
	else if (nextmail_is_mramaddr)
	{
		nextmail_is_mramaddr = false;
		u32 mramaddr = _uMail;

		struct sec_params_t {
			u16 key[2];
			u16 unk1[2];
			u16 unk2[2];
			u32 length;
			u32 dest_addr;
			u32 pad[3];
		} sec_params;

		// 32 bytes from mram addr to dram @ 0
		for (int i = 0; i < 8; i++, mramaddr += 4)
			((u32*)&sec_params)[i] = Memory_Read_U32(mramaddr);

		// This is the main decrypt routine
		u16 x11 = 0, x12 = 0,
			x20 = 0, x21 = 0, x22 = 0, x23 = 0;

		x20 = Common::swap16(sec_params.key[0]) ^ 0x6f64;
		x21 = Common::swap16(sec_params.key[1]) ^ 0x6573;

		s16 unk2 = (s8)sec_params.unk2[0];
		if (unk2 < 0)
		{
			x11 = ((~unk2 + 3) << 1) | (sec_params.unk1[0] << 4);
		}
		else if (unk2 == 0)
		{
			x11 = (sec_params.unk1[0] << 1) | 0x70;
		}
		else // unk2 > 0
		{
			x11 = ((unk2 - 1) << 1) | (sec_params.unk1[0] << 4);
		}

		s32 rounded_sub = ((sec_params.length + 7) & ~7) - 0x200;
		u16 size = (rounded_sub < 0) ? 0 : rounded_sub >> 3;

		u32 t = (((size << 16) | 0x3f80) & 0x3f80ffff) << 1;
		s16 t_low = (s8)(t >> 8);
		t += (t_low & size) << 16;
		x12 = t >> 16;
		x11 |= (size & 0x4000) >> 14; // this would be stored in ac0.h if we weren't constrained to 32bit :)
		t = ((x11 & 0xff) << 16) + ((x12 & 0xff) << 16) + (x12 << 8);

		u16 final11 = 0, final12 = 0;
		final11 = x11 | ((t >> 8) & 0xff00) | 0x8080;
		final12 = x12 | 0x8080;

		if ((final12 & 0x200) != 0)
		{
			x22 = final11 ^ 0x6f64;
			x23 = final12 ^ 0x6573;
		}
		else
		{
			x22 = final11 ^ 0x6177;
			x23 = final12 ^ 0x614b;
		}

		// Send the result back to mram
		*(u32*)Memory_Get_Pointer(sec_params.dest_addr) = Common::swap32((x20 << 16) | x21);
		*(u32*)Memory_Get_Pointer(sec_params.dest_addr+4) = Common::swap32((x22 << 16) | x23);

		// Done!
		DEBUG_LOG(DSPHLE, "\n%08x -> key %08x len %08x dest_addr %08x unk1 %08x unk2 %08x"
			" 22 %04x 23 %04x",
			mramaddr,
			*(u32*)sec_params.key, sec_params.length, sec_params.dest_addr,
			*(u32*)sec_params.unk1, *(u32*)sec_params.unk2,
			x22, x23);

		calc_done = true;
		m_rMailHandler.PushMail(DSP_DONE);
	}
	else if ((_uMail >> 16 == 0xcdd1) && calc_done)
	{
		switch (_uMail & 0xffff)
		{
		case 1:
			m_UploadSetupInProgress = true;
			break;
		case 2:
			CDSPHandler::GetInstance().SetUCode(UCODE_ROM);
			break;
		default:
			DEBUG_LOG(DSPHLE, "CUCode_GBA - unknown 0xcdd1 cmd: %08x", _uMail);
			break;
		}
	}
	else
	{
		DEBUG_LOG(DSPHLE, "CUCode_GBA - unknown cmd: %08x", _uMail);
	}
}