dolphin/Source/Plugins/Plugin_DSP_LLE/Src/gdsp_interpreter.cpp

/*====================================================================

   filename:     gdsp_interpreter.cpp
   project:      GCemu
   created:      2004-6-18
   mail:		  duddie@walla.com

   Copyright (c) 2005 Duddie & Tratax

   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; either version 2
   of the License, or (at your option) any later version.

   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 for more details.

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

   ====================================================================*/

#include <stdio.h>
#include <stdlib.h>

#include "gdsp_interface.h"
#include "gdsp_opcodes_helper.h"
#include "Tools.h"

//-------------------------------------------------------------------------------

SDSP g_dsp;

uint16 SDSP::r[32];
uint16 SDSP::pc = 0;
uint16 SDSP::err_pc = 0;
uint16* SDSP::iram   = 0;
uint16* SDSP::dram   = 0;
uint16* SDSP::irom   = 0;
uint16* SDSP::drom   = 0;
uint16* SDSP::coef   = 0;
uint8* SDSP::cpu_ram = 0;
uint16 SDSP::cr = 0;
uint8 SDSP::reg_stack_ptr[4];
// lets make stack depth to 32 for now
uint16 SDSP::reg_stack[4][DSP_STACK_DEPTH];
void (*SDSP::irq_request)() = NULL;
bool SDSP::exception_in_progress_hack = false;

// for debugger only
uint32 SDSP::iram_crc = 0;
uint64 SDSP::step_counter = 0;


//-------------------------------------------------------------------------------

static bool CR_HALT = true;
static bool CR_EXTERNAL_INT = false;

void UpdateCachedCR()
{
	CR_HALT = (g_dsp.cr & 0x4) != 0;
	CR_EXTERNAL_INT = (g_dsp.cr & 0x02) != 0;
}



//-------------------------------------------------------------------------------
void (*dsp_op[])(uint16 opc) =
{
	dsp_op0, dsp_op1, dsp_op2, dsp_op3,
	dsp_op4, dsp_op5, dsp_op6, dsp_op7,
	dsp_op8, dsp_op9, dsp_opab, dsp_opab,
	dsp_opcd, dsp_opcd, dsp_ope, dsp_opf,
};

void dbg_error(char* err_msg)
{
	return;
}


void gdsp_init()
{
	g_dsp.irom = (uint16*)malloc(DSP_IROM_SIZE * sizeof(uint16));
	g_dsp.iram = (uint16*)malloc(DSP_IRAM_SIZE * sizeof(uint16));
	g_dsp.drom = (uint16*)malloc(DSP_DROM_SIZE * sizeof(uint16));
	g_dsp.dram = (uint16*)malloc(DSP_DRAM_SIZE * sizeof(uint16));
	g_dsp.coef = (uint16*)malloc(DSP_COEF_SIZE * sizeof(uint16));

	for (int i = 0; i < DSP_IRAM_SIZE; i++)
	{
		g_dsp.iram[i] = 0x0021; // HALT opcode
	}

	for (int i = 0; i < DSP_DRAM_SIZE; i++)
	{
		g_dsp.dram[i] = 0x0021; // HALT opcode
	}

	for (int i = 0; i < 32; i++)
	{
		g_dsp.r[i] = 0;
	}

	for (int i = 0; i < 4; i++)
	{
		g_dsp.reg_stack_ptr[i] = 0;

		for (int j = 0; j < DSP_STACK_DEPTH; j++)
		{
			g_dsp.reg_stack[i][j] = 0;
		}
	}

	// copied from a real console after the custom UCode has been loaded
	g_dsp.r[0x08] = 0xffff;
	g_dsp.r[0x09] = 0xffff;
	g_dsp.r[0x0a] = 0xffff;
	g_dsp.r[0x0b] = 0xffff;

	g_dsp.cr = 0x804;
	gdsp_ifx_init();

	UpdateCachedCR();
}


void gdsp_reset()
{
//	_dbg_assert_msg_(0, "gdsp_reset()");
	_dbg_assert_msg_(!g_dsp.exception_in_progress_hack, "assert while exception");
	g_dsp.pc = DSP_RESET_VECTOR;
	g_dsp.exception_in_progress_hack = false;
}


void gdsp_generate_exception(uint8 level)
{
	_dbg_assert_msg_(!g_dsp.exception_in_progress_hack, "assert while exception");

	dsp_reg_store_stack(DSP_STACK_C, g_dsp.pc);
	dsp_reg_store_stack(DSP_STACK_D, g_dsp.r[R_SR]);

	g_dsp.pc = level * 2;

	g_dsp.exception_in_progress_hack = true;
}


uint32 gdsp_exception_ready = 0;

void gdsp_exception(uint8 level)
{
	switch (level & 0x7)
	{
	    case 0x5: // ACCA > ACCH exception

		    if (g_dsp.r[R_SR] & 0x200)
		    {
			    gdsp_exception_ready = level;
		    }

		    break;

	    default:
		    break;
	}
}


bool gdsp_load_rom(char* fname)
{
	FILE* pFile = fopen(fname, "rb");

	if (pFile)
	{
		fread(g_dsp.irom, 1, DSP_IRAM_SIZE, pFile);
		fclose(pFile);
		return(true);
	}

	return(false);
}


bool gdsp_load_coef(char* fname)
{
	FILE* pFile = fopen(fname, "rb");

	if (pFile)
	{
		fread(g_dsp.coef, 1, DSP_COEF_SIZE, pFile);
		fclose(pFile);
		return(true);
	}

	return(false);
}


void gdsp_write_cr(uint16 val)
{
	// reset
	if (val & 0x0001)
	{
		gdsp_reset();
	}

	val &= ~0x0001;

	// update cr
	g_dsp.cr = val;

	UpdateCachedCR();
}


uint16  gdsp_read_cr()
{
	if (g_dsp.pc & 0x8000)
	{
		g_dsp.cr |= 0x800;
	}
	else
	{
		g_dsp.cr &= ~0x800;
	}

	UpdateCachedCR();

	return(g_dsp.cr);
}


// special loop step.. because exception in loop or loopi fails
// dunno how we have to fix it
// atm we execute this instructions directly inside the loop command
// so it cant be interrupted by an exception
void gdsp_loop_step()
{
	g_dsp.err_pc = g_dsp.pc;
	uint16 opc = dsp_fetch_code();
	dsp_op[opc >> 12](opc);
}


void gdsp_step()
{
	g_dsp.step_counter++;

	g_dsp.err_pc = g_dsp.pc;
	uint16 opc = dsp_fetch_code();
	dsp_op[opc >> 12](opc);

	uint16& rLoopCounter = g_dsp.r[DSP_REG_ST0 + 3];

	if (rLoopCounter > 0)
	{
		const uint16& rCallAddress = g_dsp.r[DSP_REG_ST0 + 0];
		const uint16& rLoopAddress = g_dsp.r[DSP_REG_ST0 + 2];

		if (g_dsp.pc == (rLoopAddress + 1))
		{
			rLoopCounter--;

			if (rLoopCounter > 0)
			{
				g_dsp.pc = rCallAddress;
			}
			else
			{
				// end of loop
				dsp_reg_load_stack(0);
				dsp_reg_load_stack(2);
				dsp_reg_load_stack(3);
			}
		}
	}

	// check if there is an external interrupt
	if  (CR_EXTERNAL_INT)
	{
		if (dsp_SR_is_flag_set(FLAG_ENABLE_INTERUPT) && (g_dsp.exception_in_progress_hack == false))
		{
			gdsp_generate_exception(7);
			g_dsp.cr &= ~0x0002;
			UpdateCachedCR();
		}

		// level 7 is the interrupt exception
		gdsp_exception_ready = 7;
	}

}


bool gdsp_running;
extern volatile uint32 dsp_running;

bool gdsp_run()
{
	gdsp_running = true;

	while (!CR_HALT)
	{
		gdsp_step();
	}

	gdsp_running = false;
	return(true);
}


bool gdsp_runx(uint16 cnt)
{
	gdsp_running = true;

	while (!(g_dsp.cr & 0x4) && gdsp_running)
	{
		gdsp_step();
		cnt--;

		if (cnt == 0)
		{
			break;
		}
	}

	gdsp_running = false;
	return(true);
}


void gdsp_stop()
{
	gdsp_running = false;
}