/**

 * $Id$

 * 

 * MMU implementation

 *

 * 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.

 */

#define MODULE sh4_module

#include <stdio.h>

#include "sh4/sh4mmio.h"

#include "sh4/sh4core.h"

#include "mem.h"

#define VMA_TO_EXT_ADDR(vma) ((vma)&0x1FFFFFFF)

/* The MMU (practically unique in the system) is allowed to raise exceptions

 * directly, with a return code indicating that one was raised and the caller

 * had better behave appropriately.

 */

#define RAISE_TLB_ERROR(code, vpn) \

    MMIO_WRITE(MMU, TEA, vpn); \

    MMIO_WRITE(MMU, PTEH, ((MMIO_READ(MMU, PTEH) & 0x000003FF) | (vpn&0xFFFFFC00))); \

    sh4_raise_tlb_exception(code);

#define RAISE_MEM_ERROR(code, vpn) \

    MMIO_WRITE(MMU, TEA, vpn); \

    MMIO_WRITE(MMU, PTEH, ((MMIO_READ(MMU, PTEH) & 0x000003FF) | (vpn&0xFFFFFC00))); \

    sh4_raise_exception(code);

#define RAISE_OTHER_ERROR(code) \

    sh4_raise_exception(code);

/**

 * Abort with a non-MMU address error. Caused by user-mode code attempting

 * to access privileged regions, or alignment faults.

 */

#define MMU_READ_ADDR_ERROR() RAISE_OTHER_ERROR(EXC_DATA_ADDR_READ)

#define MMU_WRITE_ADDR_ERROR() RAISE_OTHER_ERROR(EXC_DATA_ADDR_WRITE)

#define MMU_TLB_READ_MISS_ERROR(vpn) RAISE_TLB_ERROR(EXC_TLB_MISS_READ, vpn)

#define MMU_TLB_WRITE_MISS_ERROR(vpn) RAISE_TLB_ERROR(EXC_TLB_MISS_WRITE, vpn)

#define MMU_TLB_INITIAL_WRITE_ERROR(vpn) RAISE_MEM_ERROR(EXC_INIT_PAGE_WRITE, vpn)

#define MMU_TLB_READ_PROT_ERROR(vpn) RAISE_MEM_ERROR(EXC_TLB_PROT_READ, vpn)

#define MMU_TLB_WRITE_PROT_ERROR(vpn) RAISE_MEM_ERROR(EXC_TLB_PROT_WRITE, vpn)

#define MMU_TLB_MULTI_HIT_ERROR(vpn) sh4_raise_reset(EXC_TLB_MULTI_HIT); \

    MMIO_WRITE(MMU, TEA, vpn); \

    MMIO_WRITE(MMU, PTEH, ((MMIO_READ(MMU, PTEH) & 0x000003FF) | (vpn&0xFFFFFC00)));

#define OCRAM_START (0x1C000000>>PAGE_BITS)

#define OCRAM_END   (0x20000000>>PAGE_BITS)

#define ITLB_ENTRY_COUNT 4

#define UTLB_ENTRY_COUNT 64

/* Entry address */

#define TLB_VALID     0x00000100

#define TLB_USERMODE  0x00000040

#define TLB_WRITABLE  0x00000020

#define TLB_USERWRITABLE (TLB_WRITABLE|TLB_USERMODE)

#define TLB_SIZE_MASK 0x00000090

#define TLB_SIZE_1K   0x00000000

#define TLB_SIZE_4K   0x00000010

#define TLB_SIZE_64K  0x00000080

#define TLB_SIZE_1M   0x00000090

#define TLB_CACHEABLE 0x00000008

#define TLB_DIRTY     0x00000004

#define TLB_SHARE     0x00000002

#define TLB_WRITETHRU 0x00000001

#define MASK_1K  0xFFFFFC00

#define MASK_4K  0xFFFFF000

#define MASK_64K 0xFFFF0000

#define MASK_1M  0xFFF00000

struct itlb_entry {

    sh4addr_t vpn; // Virtual Page Number

    uint32_t asid; // Process ID

    uint32_t mask;

    sh4addr_t ppn; // Physical Page Number

    uint32_t flags;

};

struct utlb_entry {

    sh4addr_t vpn; // Virtual Page Number

    uint32_t mask; // Page size mask

    uint32_t asid; // Process ID

    sh4addr_t ppn; // Physical Page Number

    uint32_t flags;

    uint32_t pcmcia; // extra pcmcia data - not used

};

static struct itlb_entry mmu_itlb[ITLB_ENTRY_COUNT];

static struct utlb_entry mmu_utlb[UTLB_ENTRY_COUNT];

static uint32_t mmu_urc;

static uint32_t mmu_urb;

static uint32_t mmu_lrui;

static uint32_t mmu_asid; // current asid

static sh4ptr_t cache = NULL;

static void mmu_invalidate_tlb();

static uint32_t get_mask_for_flags( uint32_t flags )

{

    switch( flags & TLB_SIZE_MASK ) {

    case TLB_SIZE_1K: return MASK_1K;

    case TLB_SIZE_4K: return MASK_4K;

    case TLB_SIZE_64K: return MASK_64K;

    case TLB_SIZE_1M: return MASK_1M;

    }

}

int32_t mmio_region_MMU_read( uint32_t reg )

{

    switch( reg ) {

    case MMUCR:

	return MMIO_READ( MMU, MMUCR) | (mmu_urc<<10) | (mmu_urb<<18) | (mmu_lrui<<26);

    default:

	return MMIO_READ( MMU, reg );

    }

}

void mmio_region_MMU_write( uint32_t reg, uint32_t val )

{

    uint32_t tmp;

    switch(reg) {

    case PTEH:

	val &= 0xFFFFFCFF;

	if( (val & 0xFF) != mmu_asid ) {

	    mmu_asid = val&0xFF;

	    sh4_icache.page_vma = -1; // invalidate icache as asid has changed

	}

	break;

    case PTEL:

	val &= 0x1FFFFDFF;

	break;

    case PTEA:

	val &= 0x0000000F;

	break;

    case MMUCR:

	if( val & MMUCR_TI ) {

	    mmu_invalidate_tlb();

	}

	mmu_urc = (val >> 10) & 0x3F;

	mmu_urb = (val >> 18) & 0x3F;

	mmu_lrui = (val >> 26) & 0x3F;

	val &= 0x00000301;

	tmp = MMIO_READ( MMU, MMUCR );

	if( ((val ^ tmp) & MMUCR_AT) && sh4_is_using_xlat() ) {

	    // AT flag has changed state - flush the xlt cache as all bets

	    // are off now. We also need to force an immediate exit from the

	    // current block

	    MMIO_WRITE( MMU, MMUCR, val );

	    sh4_translate_flush_cache();

	}

	break;

    case CCR:

	mmu_set_cache_mode( val & (CCR_OIX|CCR_ORA) );

	break;

    default:

	break;

    }

    MMIO_WRITE( MMU, reg, val );

}

void MMU_init() 

{

    cache = mem_alloc_pages(2);

}

void MMU_reset()

{

    mmio_region_MMU_write( CCR, 0 );

    mmio_region_MMU_write( MMUCR, 0 );

}

void MMU_save_state( FILE *f )

{

    fwrite( cache, 4096, 2, f );

    fwrite( &mmu_itlb, sizeof(mmu_itlb), 1, f );

    fwrite( &mmu_utlb, sizeof(mmu_utlb), 1, f );

    fwrite( &mmu_urc, sizeof(mmu_urc), 1, f );

    fwrite( &mmu_urb, sizeof(mmu_urb), 1, f );

    fwrite( &mmu_lrui, sizeof(mmu_lrui), 1, f );

    fwrite( &mmu_asid, sizeof(mmu_asid), 1, f );

}

int MMU_load_state( FILE *f )

{

    /* Setup the cache mode according to the saved register value

     * (mem_load runs before this point to load all MMIO data)

     */

    mmio_region_MMU_write( CCR, MMIO_READ(MMU, CCR) );

    if( fread( cache, 4096, 2, f ) != 2 ) {

	return 1;

    }

    if( fread( &mmu_itlb, sizeof(mmu_itlb), 1, f ) != 1 ) {

	return 1;

    }

    if( fread( &mmu_utlb, sizeof(mmu_utlb), 1, f ) != 1 ) {

	return 1;

    }

    if( fread( &mmu_urc, sizeof(mmu_urc), 1, f ) != 1 ) {

	return 1;

    }

    if( fread( &mmu_urc, sizeof(mmu_urb), 1, f ) != 1 ) {

	return 1;

    }

    if( fread( &mmu_lrui, sizeof(mmu_lrui), 1, f ) != 1 ) {

	return 1;

    }

    if( fread( &mmu_asid, sizeof(mmu_asid), 1, f ) != 1 ) {

    	return 1;

    }

    return 0;

}

void mmu_set_cache_mode( int mode )

{

    uint32_t i;

    switch( mode ) {

        case MEM_OC_INDEX0: /* OIX=0 */

            for( i=OCRAM_START; i<OCRAM_END; i++ )

                page_map[i] = cache + ((i&0x02)<<(PAGE_BITS-1));

            break;

        case MEM_OC_INDEX1: /* OIX=1 */

            for( i=OCRAM_START; i<OCRAM_END; i++ )

                page_map[i] = cache + ((i&0x02000000)>>(25-PAGE_BITS));

            break;

        default: /* disabled */

            for( i=OCRAM_START; i<OCRAM_END; i++ )

                page_map[i] = NULL;

            break;

    }

}

/* TLB maintanence */

/**

 * LDTLB instruction implementation. Copies PTEH, PTEL and PTEA into the UTLB

 * entry identified by MMUCR.URC. Does not modify MMUCR or the ITLB.

 */

void MMU_ldtlb()

{

    mmu_utlb[mmu_urc].vpn = MMIO_READ(MMU, PTEH) & 0xFFFFFC00;

    mmu_utlb[mmu_urc].asid = MMIO_READ(MMU, PTEH) & 0x000000FF;

    mmu_utlb[mmu_urc].ppn = MMIO_READ(MMU, PTEL) & 0x1FFFFC00;

    mmu_utlb[mmu_urc].flags = MMIO_READ(MMU, PTEL) & 0x00001FF;

    mmu_utlb[mmu_urc].pcmcia = MMIO_READ(MMU, PTEA);

    mmu_utlb[mmu_urc].mask = get_mask_for_flags(mmu_utlb[mmu_urc].flags);

}

static void mmu_invalidate_tlb()

{

    int i;

    for( i=0; i<ITLB_ENTRY_COUNT; i++ ) {

	mmu_itlb[i].flags &= (~TLB_VALID);

    }

    for( i=0; i<UTLB_ENTRY_COUNT; i++ ) {

	mmu_utlb[i].flags &= (~TLB_VALID);

    }

}

#define ITLB_ENTRY(addr) ((addr>>7)&0x03)

int32_t mmu_itlb_addr_read( sh4addr_t addr )

{

    struct itlb_entry *ent = &mmu_itlb[ITLB_ENTRY(addr)];

    return ent->vpn | ent->asid | (ent->flags & TLB_VALID);

}

int32_t mmu_itlb_data_read( sh4addr_t addr )

{

    struct itlb_entry *ent = &mmu_itlb[ITLB_ENTRY(addr)];

    return ent->ppn | ent->flags;

}

void mmu_itlb_addr_write( sh4addr_t addr, uint32_t val )

{

    struct itlb_entry *ent = &mmu_itlb[ITLB_ENTRY(addr)];

    ent->vpn = val & 0xFFFFFC00;

    ent->asid = val & 0x000000FF;

    ent->flags = (ent->flags & ~(TLB_VALID)) | (val&TLB_VALID);

}

void mmu_itlb_data_write( sh4addr_t addr, uint32_t val )

{

    struct itlb_entry *ent = &mmu_itlb[ITLB_ENTRY(addr)];

    ent->ppn = val & 0x1FFFFC00;

    ent->flags = val & 0x00001DA;

    ent->mask = get_mask_for_flags(val);

}

#define UTLB_ENTRY(addr) ((addr>>8)&0x3F)

#define UTLB_ASSOC(addr) (addr&0x80)

#define UTLB_DATA2(addr) (addr&0x00800000)

int32_t mmu_utlb_addr_read( sh4addr_t addr )

{

    struct utlb_entry *ent = &mmu_utlb[UTLB_ENTRY(addr)];

    return ent->vpn | ent->asid | (ent->flags & TLB_VALID) |

	((ent->flags & TLB_DIRTY)<<7);

}

int32_t mmu_utlb_data_read( sh4addr_t addr )

{

    struct utlb_entry *ent = &mmu_utlb[UTLB_ENTRY(addr)];

    if( UTLB_DATA2(addr) ) {

	return ent->pcmcia;

    } else {

	return ent->ppn | ent->flags;

    }

}

/**

 * Find a UTLB entry for the associative TLB write - same as the normal

 * lookup but ignores the valid bit.

 */

static inline mmu_utlb_lookup_assoc( uint32_t vpn, uint32_t asid )

{

    int result = -1;

    unsigned int i;

    for( i = 0; i < UTLB_ENTRY_COUNT; i++ ) {

	if( (mmu_utlb[i].flags & TLB_VALID) &&

	    ((mmu_utlb[i].flags & TLB_SHARE) || asid == mmu_utlb[i].asid) && 

	    ((mmu_utlb[i].vpn ^ vpn) & mmu_utlb[i].mask) == 0 ) {

	    if( result != -1 ) {

		fprintf( stderr, "TLB Multi hit: %d %d\n", result, i );

		return -2;

	    }

	    result = i;

	}

    }

    return result;

}

/**

 * Find a ITLB entry for the associative TLB write - same as the normal

 * lookup but ignores the valid bit.

 */

static inline mmu_itlb_lookup_assoc( uint32_t vpn, uint32_t asid )

{

    int result = -1;

    unsigned int i;

    for( i = 0; i < ITLB_ENTRY_COUNT; i++ ) {

	if( (mmu_itlb[i].flags & TLB_VALID) &&

	    ((mmu_itlb[i].flags & TLB_SHARE) || asid == mmu_itlb[i].asid) && 

	    ((mmu_itlb[i].vpn ^ vpn) & mmu_itlb[i].mask) == 0 ) {

	    if( result != -1 ) {

		return -2;

	    }

	    result = i;

	}

    }

    return result;

}

void mmu_utlb_addr_write( sh4addr_t addr, uint32_t val )

{

    if( UTLB_ASSOC(addr) ) {

	int utlb = mmu_utlb_lookup_assoc( val, mmu_asid );

	if( utlb >= 0 ) {

	    struct utlb_entry *ent = &mmu_utlb[utlb];

	    ent->flags = ent->flags & ~(TLB_DIRTY|TLB_VALID);

	    ent->flags |= (val & TLB_VALID);

	    ent->flags |= ((val & 0x200)>>7);

	}

	int itlb = mmu_itlb_lookup_assoc( val, mmu_asid );

	if( itlb >= 0 ) {

	    struct itlb_entry *ent = &mmu_itlb[itlb];

	    ent->flags = (ent->flags & (~TLB_VALID)) | (val & TLB_VALID);

	}

	if( itlb == -2 || utlb == -2 ) {

	    MMU_TLB_MULTI_HIT_ERROR(addr);

	    return;

	}

    } else {

	struct utlb_entry *ent = &mmu_utlb[UTLB_ENTRY(addr)];

	ent->vpn = (val & 0xFFFFFC00);

	ent->asid = (val & 0xFF);

	ent->flags = (ent->flags & ~(TLB_DIRTY|TLB_VALID));

	ent->flags |= (val & TLB_VALID);

	ent->flags |= ((val & 0x200)>>7);

    }

}

void mmu_utlb_data_write( sh4addr_t addr, uint32_t val )

{

    struct utlb_entry *ent = &mmu_utlb[UTLB_ENTRY(addr)];

    if( UTLB_DATA2(addr) ) {

	ent->pcmcia = val & 0x0000000F;

    } else {

	ent->ppn = (val & 0x1FFFFC00);

	ent->flags = (val & 0x000001FF);

	ent->mask = get_mask_for_flags(val);

    }

}

/* Cache access - not implemented */

int32_t mmu_icache_addr_read( sh4addr_t addr )

{

    return 0; // not implemented

}

int32_t mmu_icache_data_read( sh4addr_t addr )

{

    return 0; // not implemented

}

int32_t mmu_ocache_addr_read( sh4addr_t addr )

{

    return 0; // not implemented

}

int32_t mmu_ocache_data_read( sh4addr_t addr )

{

    return 0; // not implemented

}

void mmu_icache_addr_write( sh4addr_t addr, uint32_t val )

{

}

void mmu_icache_data_write( sh4addr_t addr, uint32_t val )

{

}

void mmu_ocache_addr_write( sh4addr_t addr, uint32_t val )

{

}

void mmu_ocache_data_write( sh4addr_t addr, uint32_t val )

{

}

/******************************************************************************/

/*                        MMU TLB address translation                         */

/******************************************************************************/

/**

 * The translations are excessively complicated, but unfortunately it's a 

 * complicated system. TODO: make this not be painfully slow.

 */

/**

 * Perform the actual utlb lookup w/ asid matching.

 * Possible utcomes are:

 *   0..63 Single match - good, return entry found

 *   -1 No match - raise a tlb data miss exception

 *   -2 Multiple matches - raise a multi-hit exception (reset)

 * @param vpn virtual address to resolve

 * @return the resultant UTLB entry, or an error.

 */

static inline int mmu_utlb_lookup_vpn_asid( uint32_t vpn )

{

    int result = -1;

    unsigned int i;

    mmu_urc++;

    if( mmu_urc == mmu_urb || mmu_urc == 0x40 ) {

	mmu_urc = 0;

    }

    for( i = 0; i < UTLB_ENTRY_COUNT; i++ ) {

	if( (mmu_utlb[i].flags & TLB_VALID) &&

	    ((mmu_utlb[i].flags & TLB_SHARE) || mmu_asid == mmu_utlb[i].asid) && 

	    ((mmu_utlb[i].vpn ^ vpn) & mmu_utlb[i].mask) == 0 ) {

	    if( result != -1 ) {

		return -2;

	    }

	    result = i;

	}

    }

    return result;

}

/**

 * Perform the actual utlb lookup matching on vpn only

 * Possible utcomes are:

 *   0..63 Single match - good, return entry found

 *   -1 No match - raise a tlb data miss exception

 *   -2 Multiple matches - raise a multi-hit exception (reset)

 * @param vpn virtual address to resolve

 * @return the resultant UTLB entry, or an error.

 */

static inline int mmu_utlb_lookup_vpn( uint32_t vpn )

{

    int result = -1;

    unsigned int i;

    mmu_urc++;

    if( mmu_urc == mmu_urb || mmu_urc == 0x40 ) {

	mmu_urc = 0;

    }

    for( i = 0; i < UTLB_ENTRY_COUNT; i++ ) {

	if( (mmu_utlb[i].flags & TLB_VALID) &&

	    ((mmu_utlb[i].vpn ^ vpn) & mmu_utlb[i].mask) == 0 ) {

	    if( result != -1 ) {

		return -2;

	    }

	    result = i;

	}

    }

    return result;

}

/**

 * Update the ITLB by replacing the LRU entry with the specified UTLB entry.

 * @return the number (0-3) of the replaced entry.

 */

static int inline mmu_itlb_update_from_utlb( int entryNo )

{

    int replace;

    /* Determine entry to replace based on lrui */

    if( (mmu_lrui & 0x38) == 0x38 ) {

	replace = 0;

	mmu_lrui = mmu_lrui & 0x07;

    } else if( (mmu_lrui & 0x26) == 0x06 ) {

	replace = 1;

	mmu_lrui = (mmu_lrui & 0x19) | 0x20;

    } else if( (mmu_lrui & 0x15) == 0x01 ) {

	replace = 2;

	mmu_lrui = (mmu_lrui & 0x3E) | 0x14;

    } else { // Note - gets invalid entries too

	replace = 3;

	mmu_lrui = (mmu_lrui | 0x0B);

    } 

    mmu_itlb[replace].vpn = mmu_utlb[entryNo].vpn;

    mmu_itlb[replace].mask = mmu_utlb[entryNo].mask;

    mmu_itlb[replace].ppn = mmu_utlb[entryNo].ppn;

    mmu_itlb[replace].asid = mmu_utlb[entryNo].asid;

    mmu_itlb[replace].flags = mmu_utlb[entryNo].flags & 0x01DA;

    return replace;

}

/**

 * Perform the actual itlb lookup w/ asid protection

 * Possible utcomes are:

 *   0..63 Single match - good, return entry found

 *   -1 No match - raise a tlb data miss exception

 *   -2 Multiple matches - raise a multi-hit exception (reset)

 * @param vpn virtual address to resolve

 * @return the resultant ITLB entry, or an error.

 */

static inline int mmu_itlb_lookup_vpn_asid( uint32_t vpn )

{

    int result = -1;

    unsigned int i;

    for( i = 0; i < ITLB_ENTRY_COUNT; i++ ) {

	if( (mmu_itlb[i].flags & TLB_VALID) &&

	    ((mmu_itlb[i].flags & TLB_SHARE) || mmu_asid == mmu_itlb[i].asid) && 

	    ((mmu_itlb[i].vpn ^ vpn) & mmu_itlb[i].mask) == 0 ) {

	    if( result != -1 ) {

		return -2;

	    }

	    result = i;

	}

    }

    if( result == -1 ) {

	int utlbEntry = mmu_utlb_lookup_vpn_asid( vpn );

	if( utlbEntry < 0 ) {

	    return utlbEntry;

	} else {

	    return mmu_itlb_update_from_utlb( utlbEntry );

	}

    }

    switch( result ) {

    case 0: mmu_lrui = (mmu_lrui & 0x07); break;

    case 1: mmu_lrui = (mmu_lrui & 0x19) | 0x20; break;

    case 2: mmu_lrui = (mmu_lrui & 0x3E) | 0x14; break;

    case 3: mmu_lrui = (mmu_lrui | 0x0B); break;

    }

    return result;

}

/**

 * Perform the actual itlb lookup on vpn only

 * Possible utcomes are:

 *   0..63 Single match - good, return entry found

 *   -1 No match - raise a tlb data miss exception

 *   -2 Multiple matches - raise a multi-hit exception (reset)

 * @param vpn virtual address to resolve

 * @return the resultant ITLB entry, or an error.

 */

static inline int mmu_itlb_lookup_vpn( uint32_t vpn )

{

    int result = -1;

    unsigned int i;

    for( i = 0; i < ITLB_ENTRY_COUNT; i++ ) {

	if( (mmu_itlb[i].flags & TLB_VALID) &&

	    ((mmu_itlb[i].vpn ^ vpn) & mmu_itlb[i].mask) == 0 ) {

	    if( result != -1 ) {

		return -2;

	    }

	    result = i;

	}

    }

    if( result == -1 ) {

	int utlbEntry = mmu_utlb_lookup_vpn( vpn );

	if( utlbEntry < 0 ) {

	    return utlbEntry;

	} else {

	    return mmu_itlb_update_from_utlb( utlbEntry );

	}

    }

    switch( result ) {

    case 0: mmu_lrui = (mmu_lrui & 0x07); break;

    case 1: mmu_lrui = (mmu_lrui & 0x19) | 0x20; break;

    case 2: mmu_lrui = (mmu_lrui & 0x3E) | 0x14; break;

    case 3: mmu_lrui = (mmu_lrui | 0x0B); break;

    }

    return result;

}

sh4addr_t mmu_vma_to_phys_read( sh4vma_t addr )

{

    uint32_t mmucr = MMIO_READ(MMU,MMUCR);

    if( addr & 0x80000000 ) {

	if( IS_SH4_PRIVMODE() ) {

	    if( addr >= 0xE0000000 ) {

		return addr; /* P4 - passthrough */

	    } else if( addr < 0xC0000000 ) {

		/* P1, P2 regions are pass-through (no translation) */

		return VMA_TO_EXT_ADDR(addr);

	    }

	} else {

	    if( addr >= 0xE0000000 && addr < 0xE4000000 &&

		((mmucr&MMUCR_SQMD) == 0) ) {

		/* Conditional user-mode access to the store-queue (no translation) */

		return addr;

	    }

	    MMU_READ_ADDR_ERROR();

	    return MMU_VMA_ERROR;

	}

    }

    if( (mmucr & MMUCR_AT) == 0 ) {

	return VMA_TO_EXT_ADDR(addr);

    }

    /* If we get this far, translation is required */

    int entryNo;

    if( ((mmucr & MMUCR_SV) == 0) || !IS_SH4_PRIVMODE() ) {

	entryNo = mmu_utlb_lookup_vpn_asid( addr );

    } else {

	entryNo = mmu_utlb_lookup_vpn( addr );

    }

    switch(entryNo) {

    case -1:

	MMU_TLB_READ_MISS_ERROR(addr);

	return MMU_VMA_ERROR;

    case -2:

	MMU_TLB_MULTI_HIT_ERROR(addr);

	return MMU_VMA_ERROR;

    default:

	if( (mmu_utlb[entryNo].flags & TLB_USERMODE) == 0 &&

	    !IS_SH4_PRIVMODE() ) {

	    /* protection violation */

	    MMU_TLB_READ_PROT_ERROR(addr);

	    return MMU_VMA_ERROR;

	}

	/* finally generate the target address */

	return (mmu_utlb[entryNo].ppn & mmu_utlb[entryNo].mask) | 

	    (addr & (~mmu_utlb[entryNo].mask));

    }

}

sh4addr_t mmu_vma_to_phys_write( sh4vma_t addr )

{

    uint32_t mmucr = MMIO_READ(MMU,MMUCR);

    if( addr & 0x80000000 ) {

	if( IS_SH4_PRIVMODE() ) {

	    if( addr >= 0xE0000000 ) {

		return addr; /* P4 - passthrough */

	    } else if( addr < 0xC0000000 ) {

		/* P1, P2 regions are pass-through (no translation) */

		return VMA_TO_EXT_ADDR(addr);

	    }

	} else {

	    if( addr >= 0xE0000000 && addr < 0xE4000000 &&

		((mmucr&MMUCR_SQMD) == 0) ) {

		/* Conditional user-mode access to the store-queue (no translation) */

		return addr;

	    }

	    MMU_WRITE_ADDR_ERROR();

	    return MMU_VMA_ERROR;

	}

    }

    if( (mmucr & MMUCR_AT) == 0 ) {

	return VMA_TO_EXT_ADDR(addr);

    }

    /* If we get this far, translation is required */

    int entryNo;

    if( ((mmucr & MMUCR_SV) == 0) || !IS_SH4_PRIVMODE() ) {

	entryNo = mmu_utlb_lookup_vpn_asid( addr );

    } else {

	entryNo = mmu_utlb_lookup_vpn( addr );

    }

    switch(entryNo) {

    case -1:

	MMU_TLB_WRITE_MISS_ERROR(addr);

	return MMU_VMA_ERROR;

    case -2:

	MMU_TLB_MULTI_HIT_ERROR(addr);

	return MMU_VMA_ERROR;

    default:

	if( IS_SH4_PRIVMODE() ? ((mmu_utlb[entryNo].flags & TLB_WRITABLE) == 0)

	    : ((mmu_utlb[entryNo].flags & TLB_USERWRITABLE) != TLB_USERWRITABLE) ) {

	    /* protection violation */

	    MMU_TLB_WRITE_PROT_ERROR(addr);

	    return MMU_VMA_ERROR;

	}

	if( (mmu_utlb[entryNo].flags & TLB_DIRTY) == 0 ) {

	    MMU_TLB_INITIAL_WRITE_ERROR(addr);

	    return MMU_VMA_ERROR;

	}

	/* finally generate the target address */

	return (mmu_utlb[entryNo].ppn & mmu_utlb[entryNo].mask) | 

	    (addr & (~mmu_utlb[entryNo].mask));

    }

}

/**

 * Update the icache for an untranslated address

 */

void mmu_update_icache_phys( sh4addr_t addr )

{

    if( (addr & 0x1C000000) == 0x0C000000 ) {

	/* Main ram */

	sh4_icache.page_vma = addr & 0xFF000000;

	sh4_icache.page_ppa = 0x0C000000;

	sh4_icache.mask = 0xFF000000;

	sh4_icache.page = sh4_main_ram;

    } else if( (addr & 0x1FE00000) == 0 ) {

	/* BIOS ROM */

	sh4_icache.page_vma = addr & 0xFFE00000;

	sh4_icache.page_ppa = 0;

	sh4_icache.mask = 0xFFE00000;

	sh4_icache.page = mem_get_region(0);

    } else {

	/* not supported */

	sh4_icache.page_vma = -1;

    }

}

/**

 * Update the sh4_icache structure to describe the page(s) containing the

 * given vma. If the address does not reference a RAM/ROM region, the icache

 * will be invalidated instead.

 * If AT is on, this method will raise TLB exceptions normally

 * (hence this method should only be used immediately prior to execution of

 * code), and otherwise will set the icache according to the matching TLB entry.

 * If AT is off, this method will set the entire referenced RAM/ROM region in

 * the icache.

 * @return TRUE if the update completed (successfully or otherwise), FALSE

 * if an exception was raised.

 */

gboolean mmu_update_icache( sh4vma_t addr )

{

    int entryNo;

    if( IS_SH4_PRIVMODE()  ) {

	if( addr & 0x80000000 ) {

	    if( addr < 0xC0000000 ) {

		/* P1, P2 and P4 regions are pass-through (no translation) */

		mmu_update_icache_phys(addr);

		return TRUE;

	    } else if( addr >= 0xE0000000 && addr < 0xFFFFFF00 ) {

		MMU_READ_ADDR_ERROR();

		return FALSE;

	    }

	}

	uint32_t mmucr = MMIO_READ(MMU,MMUCR);

	if( (mmucr & MMUCR_AT) == 0 ) {

	    mmu_update_icache_phys(addr);

	    return TRUE;

	}

	entryNo = mmu_itlb_lookup_vpn( addr );

    } else {

	if( addr & 0x80000000 ) {

	    MMU_READ_ADDR_ERROR();

	    return FALSE;

	}

	uint32_t mmucr = MMIO_READ(MMU,MMUCR);

	if( (mmucr & MMUCR_AT) == 0 ) {

	    mmu_update_icache_phys(addr);

	    return TRUE;

	}

	if( mmucr & MMUCR_SV ) {

	    entryNo = mmu_itlb_lookup_vpn( addr );

	} else {

	    entryNo = mmu_itlb_lookup_vpn_asid( addr );

	}

	if( entryNo != -1 && (mmu_itlb[entryNo].flags & TLB_USERMODE) == 0 ) {

	    MMU_TLB_READ_PROT_ERROR(addr);

	    return FALSE;

	}

    }

    switch(entryNo) {

    case -1:

	MMU_TLB_READ_MISS_ERROR(addr);

	return FALSE;

    case -2:

	MMU_TLB_MULTI_HIT_ERROR(addr);

	return FALSE;

    default:

	sh4_icache.page_ppa = mmu_itlb[entryNo].ppn & mmu_itlb[entryNo].mask;

	sh4_icache.page = mem_get_region( sh4_icache.page_ppa );

	if( sh4_icache.page == NULL ) {

	    sh4_icache.page_vma = -1;

	} else {

	    sh4_icache.page_vma = mmu_itlb[entryNo].vpn & mmu_itlb[entryNo].mask;

	    sh4_icache.mask = mmu_itlb[entryNo].mask;

	}

	return TRUE;

    }

}

gboolean sh4_flush_store_queue( sh4addr_t addr )

{

    uint32_t mmucr = MMIO_READ(MMU,MMUCR);

    int queue = (addr&0x20)>>2;

    sh4ptr_t src = (sh4ptr_t)&sh4r.store_queue[queue];

    sh4addr_t target;

    /* Store queue operation */

    if( mmucr & MMUCR_AT ) {

	int entryNo;

	if( ((mmucr & MMUCR_SV) == 0) || !IS_SH4_PRIVMODE() ) {

	    entryNo = mmu_utlb_lookup_vpn_asid( addr );

	} else {

	    entryNo = mmu_utlb_lookup_vpn( addr );

	}

	switch(entryNo) {

	case -1:

	    MMU_TLB_WRITE_MISS_ERROR(addr);

	    return FALSE;

	case -2:

	    MMU_TLB_MULTI_HIT_ERROR(addr);

	    return FALSE;

	default:

	    if( IS_SH4_PRIVMODE() ? ((mmu_utlb[entryNo].flags & TLB_WRITABLE) == 0)

		: ((mmu_utlb[entryNo].flags & TLB_USERWRITABLE) != TLB_USERWRITABLE) ) {

		/* protection violation */

		MMU_TLB_WRITE_PROT_ERROR(addr);

		return FALSE;

	    }

	    if( (mmu_utlb[entryNo].flags & TLB_DIRTY) == 0 ) {

		MMU_TLB_INITIAL_WRITE_ERROR(addr);

		return FALSE;

	    }

	    /* finally generate the target address */

	    target = ((mmu_utlb[entryNo].ppn & mmu_utlb[entryNo].mask) | 

		      (addr & (~mmu_utlb[entryNo].mask))) & 0xFFFFFFE0;

	}

    } else {

	uint32_t hi = (MMIO_READ( MMU, (queue == 0 ? QACR0 : QACR1) ) & 0x1C) << 24;

	target = (addr&0x03FFFFE0) | hi;

    }

    mem_copy_to_sh4( target, src, 32 );

    return TRUE;

}