/**

 * $Id$

 * 

 * SH4 translation core module. This part handles the non-target-specific

 * section of the translation.

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * 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.

 */

#include <assert.h>

#include <setjmp.h>

#include "eventq.h"

#include "syscall.h"

#include "clock.h"

#include "sh4/sh4core.h"

#include "sh4/sh4trans.h"

#include "sh4/xltcache.h"

static jmp_buf xlat_jmp_buf;

/**

 * Execute a timeslice using translated code only (ie translate/execute loop)

 * Note this version does not support breakpoints

 */

uint32_t sh4_xlat_run_slice( uint32_t nanosecs ) 

{

    sh4r.slice_cycle = 0;

    if( sh4r.sh4_state != SH4_STATE_RUNNING ) {

	if( sh4r.event_pending < nanosecs ) {

	    sh4r.sh4_state = SH4_STATE_RUNNING;

	    sh4r.slice_cycle = sh4r.event_pending;

	}

    }

    int jmp = setjmp(xlat_jmp_buf);

    void * (*code)() = NULL;

    while( sh4r.slice_cycle < nanosecs ) {

	if( sh4r.event_pending <= sh4r.slice_cycle ) {

	    if( sh4r.event_types & PENDING_EVENT ) {

		event_execute();

	    }

	    /* Eventq execute may (quite likely) deliver an immediate IRQ */

	    if( sh4r.event_types & PENDING_IRQ ) {

		sh4_accept_interrupt();

		code = NULL;

	    }

	}

	if( code == NULL ) {

	    if( sh4r.pc > 0xFFFFFF00 ) {

		syscall_invoke( sh4r.pc );

		sh4r.in_delay_slot = 0;

		sh4r.pc = sh4r.pr;

	    }

	    code = xlat_get_code_by_vma( sh4r.pc );

	    if( code == NULL ) {

		code = sh4_translate_basic_block( sh4r.pc );

	    }

	}

	code = code();

    }

    if( sh4r.sh4_state != SH4_STATE_STANDBY ) {

	TMU_run_slice( nanosecs );

	SCIF_run_slice( nanosecs );

    }

    return nanosecs;

}

uint8_t *xlat_output;

struct xlat_recovery_record xlat_recovery[MAX_RECOVERY_SIZE];

uint32_t xlat_recovery_posn;

/**

 * Translate a linear basic block, ie all instructions from the start address

 * (inclusive) until the next branch/jump instruction or the end of the page

 * is reached.

 * @return the address of the translated block

 * eg due to lack of buffer space.

 */

void * sh4_translate_basic_block( sh4addr_t start )

{

    sh4addr_t pc = start;

    sh4addr_t lastpc = (pc&0xFFFFF000)+0x1000;

    int done;

    xlat_cache_block_t block = xlat_start_block( start );

    xlat_output = (uint8_t *)block->code;

    xlat_recovery_posn = 0;

    uint8_t *eob = xlat_output + block->size;

    sh4_translate_begin_block(pc);

    do {

	if( eob - xlat_output < MAX_INSTRUCTION_SIZE ) {

	    uint8_t *oldstart = block->code;

	    block = xlat_extend_block( xlat_output - oldstart + MAX_INSTRUCTION_SIZE );

	    xlat_output = block->code + (xlat_output - oldstart);

	    eob = block->code + block->size;

	}

	done = sh4_translate_instruction( pc ); 

	assert( xlat_output <= eob );

	pc += 2;

	if ( pc >= lastpc ) {

	    done = 2;

	}

    } while( !done );

    pc += (done - 2);

    if( eob - xlat_output < EPILOGUE_SIZE ) {

	uint8_t *oldstart = block->code;

	block = xlat_extend_block( xlat_output - oldstart + EPILOGUE_SIZE );

	xlat_output = block->code + (xlat_output - oldstart);

    }	

    sh4_translate_end_block(pc);

    /* Write the recovery records onto the end of the code block */

    uint32_t recovery_size = sizeof(struct xlat_recovery_record)*xlat_recovery_posn;

    uint32_t finalsize = xlat_output - block->code + recovery_size;

    if( finalsize > block->size ) {

	uint8_t *oldstart = block->code;

	block = xlat_extend_block( finalsize );

	xlat_output = block->code + (xlat_output - oldstart);

    }

    memcpy( xlat_output, xlat_recovery, recovery_size);

    block->recover_table = (xlat_recovery_record_t)xlat_output;

    block->recover_table_size = xlat_recovery_posn;

    xlat_commit_block( finalsize, pc-start );

    return block->code;

}

/**

 * Translate a linear basic block to a temporary buffer, execute it, and return

 * the result of the execution. The translation is discarded.

 */

void *sh4_translate_and_run( sh4addr_t start )

{

    unsigned char buf[65536];

    sh4addr_t pc = start;

    int done;

    xlat_output = buf;

    uint8_t *eob = xlat_output + sizeof(buf);

    sh4_translate_begin_block(pc);

    while( (done = sh4_translate_instruction( pc )) == 0 ) {

	assert( (eob - xlat_output) >= MAX_INSTRUCTION_SIZE );

	pc += 2;

    }

    pc+=2;

    sh4_translate_end_block(pc);

    void * (*code)() = (void *)buf;

    return code();

}

/**

 * "Execute" the supplied recovery record. Currently this only updates

 * sh4r.pc and sh4r.slice_cycle according to the currently executing

 * instruction. In future this may be more sophisticated (ie will

 * call into generated code).

 */

void sh4_translate_run_recovery( xlat_recovery_record_t recovery )

{

    sh4r.slice_cycle += (recovery->sh4_icount * sh4_cpu_period);

    sh4r.pc += (recovery->sh4_icount<<1);

}

void sh4_translate_unwind_stack( gboolean abort_after, unwind_thunk_t thunk )

{

    void *pc = xlat_get_native_pc();

    if( pc == NULL ) {

	// This should never happen - indicative of a bug somewhere.

	FATAL("Attempted to unwind stack, but translator is not running or stack is corrupt");

    }

    void *code = xlat_get_code( sh4r.pc );

    xlat_recovery_record_t recover = xlat_get_recovery(code, pc, TRUE);

    if( recover != NULL ) {

	// Can be null if there is no recovery necessary

	sh4_translate_run_recovery(recover);

    }

    if( thunk != NULL ) {

	thunk();

    }

    // finally longjmp back into sh4_xlat_run_slice

    longjmp(xlat_jmp_buf, 1);

} 

/**

 * Exit the current block at the end of the current instruction, flush the

 * translation cache (completely) and return control to sh4_xlat_run_slice.

 *

 * As a special case, if the current instruction is actually the last 

 * instruction in the block (ie it's in a delay slot), this function 

 * returns to allow normal completion of the translation block. Otherwise

 * this function never returns.

 *

 * Must only be invoked (indirectly) from within translated code.

 */

void sh4_translate_flush_cache()

{

    void *pc = xlat_get_native_pc();

    if( pc == NULL ) {

	// This should never happen - indicative of a bug somewhere.

	FATAL("Attempted to unwind stack, but translator is not running or stack is corrupt");

    }

    void *code = xlat_get_code( sh4r.pc );

    xlat_recovery_record_t recover = xlat_get_recovery(code, pc, TRUE);

    if( recover != NULL ) {

	// Can be null if there is no recovery necessary

	sh4_translate_run_recovery(recover);

	xlat_flush_cache();

	longjmp(xlat_jmp_buf, 1);

    } else {

	xlat_flush_cache();

	return;

    }

}

void *xlat_get_code_by_vma( sh4vma_t vma )

{

    void *result = NULL;

    if( !IS_IN_ICACHE(vma) ) {

	if( !mmu_update_icache(sh4r.pc) ) {

	    // fault - off to the fault handler

	    if( !mmu_update_icache(sh4r.pc) ) {

		// double fault - halt

		dreamcast_stop();

		ERROR( "Double fault - halting" );

		return NULL;

	    }

	}

    }

    if( sh4_icache.page_vma != -1 ) {

	result = xlat_get_code( GET_ICACHE_PHYS(vma) );

    }

    return result;

}