/**

  * $Id$

  * 

  * 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;

     }

 }

 /**

  * Translate address for disassembly purposes (ie performs an instruction 

  * lookup) - does not raise exceptions or modify any state, and ignores

  * protection bits. Returns the translated address, or MMU_VMA_ERROR

  * on translation failure. 

  */

 sh4addr_t mmu_vma_to_phys_disasm( sh4vma_t vma )

 {

     if( vma & 0x80000000 ) {

 	if( vma < 0xC0000000 ) {

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

 	    return VMA_TO_EXT_ADDR(vma);

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

 	    /* Not translatable */

 	    return MMU_VMA_ERROR;

 	}

     }

     uint32_t mmucr = MMIO_READ(MMU,MMUCR);

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

 	return VMA_TO_EXT_ADDR(vma);

     }

     int entryNo = mmu_itlb_lookup_vpn( vma );

     if( entryNo == -2 ) {

 	entryNo = mmu_itlb_lookup_vpn_asid( vma );

     }

     if( entryNo < 0 ) {

 	return MMU_VMA_ERROR;

     } else {

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

 	    (vma & (~mmu_itlb[entryNo].mask));	

     }

 }

 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;

 }