/**

 * $Id$

 * 

 * 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 "eventq.h"

#include "syscall.h"

#include "clock.h"

#include "dreamcast.h"

#include "sh4/sh4core.h"

#include "sh4/sh4trans.h"

#include "sh4/sh4mmio.h"

#include "sh4/mmu.h"

#include "xlat/xltcache.h"

/**

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

 */

uint32_t sh4_translate_run_slice( uint32_t nanosecs ) 

{

    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( IS_SYSCALL(sh4r.pc) ) {

                syscall_invoke( sh4r.pc );

                sh4r.in_delay_slot = 0;

                sh4r.pc = sh4r.pr;

            }

            code = xlat_get_code_by_vma( sh4r.pc );

            if( code == NULL || sh4r.xlat_sh4_mode != XLAT_BLOCK_MODE(code) ) {

                code = sh4_translate_basic_block( sh4r.pc );

            }

        } else if( sh4r.xlat_sh4_mode != XLAT_BLOCK_MODE(code) ) {

            if( !IS_IN_ICACHE(sh4r.pc) ) {

                /* If TLB is off, we may have gotten here without updating

                 * the icache, so do it now. This should never fail, so...

                 */

                mmu_update_icache(sh4r.pc);

                assert( IS_IN_ICACHE(sh4r.pc) ); 

            }

            code = sh4_translate_basic_block( sh4r.pc );

        }

        code = code();

    }

    return nanosecs;

}

uint8_t *xlat_output;

xlat_cache_block_t xlat_current_block;

struct xlat_recovery_record xlat_recovery[MAX_RECOVERY_SIZE];

uint32_t xlat_recovery_posn;

void sh4_translate_add_recovery( uint32_t icount )

{

    xlat_recovery[xlat_recovery_posn].xlat_offset = 

        ((uintptr_t)xlat_output) - ((uintptr_t)xlat_current_block->code);

    xlat_recovery[xlat_recovery_posn].sh4_icount = icount;

    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.

 * @param start VMA of the block start (which must already be in the icache)

 * @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, i;

    xlat_current_block = xlat_start_block( GET_ICACHE_PHYS(start) );

    xlat_output = (uint8_t *)xlat_current_block->code;

    xlat_recovery_posn = 0;

    uint8_t *eob = xlat_output + xlat_current_block->size;

    if( GET_ICACHE_END() < lastpc ) {

        lastpc = GET_ICACHE_END();

    }

    sh4_translate_begin_block(pc);

    do {

        if( eob - xlat_output < MAX_INSTRUCTION_SIZE ) {

            uint8_t *oldstart = xlat_current_block->code;

            xlat_current_block = xlat_extend_block( xlat_output - oldstart + MAX_INSTRUCTION_SIZE );

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

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

        }

        done = sh4_translate_instruction( pc ); 

        assert( xlat_output <= eob );

        pc += 2;

        if ( pc >= lastpc ) {

            done = 2;

        }

    } while( !done );

    pc += (done - 2);

    // Add end-of-block recovery for post-instruction checks

    sh4_translate_add_recovery( (pc - start)>>1 ); 

    int epilogue_size = sh4_translate_end_block_size();

    uint32_t recovery_size = sizeof(struct xlat_recovery_record)*xlat_recovery_posn;

    uint32_t finalsize = (xlat_output - xlat_current_block->code) + epilogue_size + recovery_size;

    if( xlat_current_block->size < finalsize ) {

        uint8_t *oldstart = xlat_current_block->code;

        xlat_current_block = xlat_extend_block( finalsize );

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

    }	

    sh4_translate_end_block(pc);

    assert( xlat_output <= (xlat_current_block->code + xlat_current_block->size - recovery_size) );

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

    memcpy( xlat_output, xlat_recovery, recovery_size);

    xlat_current_block->recover_table_offset = xlat_output - (uint8_t *)xlat_current_block->code;

    xlat_current_block->recover_table_size = xlat_recovery_posn;

    xlat_current_block->xlat_sh4_mode = sh4r.xlat_sh4_mode;

    xlat_commit_block( finalsize, pc-start );

    return xlat_current_block->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);

}

/**

 * Same as sh4_translate_run_recovery, but is used to recover from a taken

 * exception - that is, it fixes sh4r.spc rather than sh4r.pc

 */

void sh4_translate_run_exception_recovery( xlat_recovery_record_t recovery )

{

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

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

}    

void sh4_translate_exit_recover( )

{

    void *code = xlat_get_code_by_vma( sh4r.pc );

    if( code != NULL ) {

        uint32_t size = xlat_get_code_size( code );

        void *pc = xlat_get_native_pc( code, size );

        if( pc != NULL ) {

            // could be null if we're not actually running inside the translator

            xlat_recovery_record_t recover = xlat_get_pre_recovery(code, pc);

            if( recover != NULL ) {

                // Can be null if there is no recovery necessary

                sh4_translate_run_recovery(recover);

            }

        }

    }

}

void sh4_translate_exception_exit_recover( )

{

    void *code = xlat_get_code_by_vma( sh4r.spc );

    if( code != NULL ) {

        uint32_t size = xlat_get_code_size( code );

        void *pc = xlat_get_native_pc( code, size );

        if( pc != NULL ) {

            // could be null if we're not actually running inside the translator

            xlat_recovery_record_t recover = xlat_get_pre_recovery(code, pc);

            if( recover != NULL ) {

                // Can be null if there is no recovery necessary

                sh4_translate_run_exception_recovery(recover);

            }

        }

    }

}

void FASTCALL sh4_translate_breakpoint_hit(uint32_t pc)

{

    if( sh4_starting && sh4r.slice_cycle == 0 && pc == sh4r.pc ) {

        return;

    }

    sh4_core_exit( CORE_EXIT_BREAKPOINT );

}

void * FASTCALL xlat_get_code_by_vma( sh4vma_t vma )

{

    void *result = NULL;

    if( IS_IN_ICACHE(vma) ) {

        return xlat_get_code( GET_ICACHE_PHYS(vma) );

    }

    if( IS_SYSCALL(vma) ) {

        // lxdream hook

        return NULL;

    }

    if( !mmu_update_icache(vma) ) {

        // fault - off to the fault handler

        if( !mmu_update_icache(sh4r.pc) ) {

            // double fault - halt

            ERROR( "Double fault - halting" );

            sh4_core_exit(CORE_EXIT_HALT);

            return NULL;

        }

    }

    assert( IS_IN_ICACHE(sh4r.pc) );

    result = xlat_get_code( GET_ICACHE_PHYS(sh4r.pc) );

    return result;

}