/**

 * $Id$

 *

 * 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 <assert.h>

#include "sh4/sh4mmio.h"

#include "sh4/sh4core.h"

#include "sh4/sh4trans.h"

#include "mem.h"

#ifdef HAVE_FRAME_ADDRESS

#define RETURN_VIA(exc) do{ *(((void **)__builtin_frame_address(0))+1) = exc; return; } while(0)

#else

#define RETURN_VIA(exc) return MMU_VMA_ERROR

#endif

#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>>LXDREAM_PAGE_BITS)

#define OCRAM_END   (0x20000000>>LXDREAM_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

};

struct utlb_sort_entry {

    sh4addr_t key; // Masked VPN + ASID

    uint32_t mask; // Mask + 0x00FF

    int entryNo;

};

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 struct utlb_sort_entry mmu_utlb_sorted[UTLB_ENTRY_COUNT];

static uint32_t mmu_utlb_entries; // Number of entries in mmu_utlb_sorted. 

static sh4ptr_t cache = NULL;

static void mmu_invalidate_tlb();

static void mmu_utlb_sorted_reset();

static void mmu_utlb_sorted_reload(); 

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;

    default: return 0; /* Unreachable */

    }

}

MMIO_REGION_READ_FN( MMU, reg )

{

    reg &= 0xFFF;

    switch( reg ) {

    case MMUCR:

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

    default:

        return MMIO_READ( MMU, reg );

    }

}

MMIO_REGION_WRITE_FN( MMU, reg, val )

{

    uint32_t tmp;

    reg &= 0xFFF;

    switch(reg) {

    case SH4VER:

        return;

    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 TRA:

    	val &= 0x000003FC;

    	break;

    case EXPEVT:

    case INTEVT:

    	val &= 0x00000FFF;

    	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|MMUCR_SV) ) {

            // 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_flush_icache();

        }

        break;

    case CCR:

        mmu_set_cache_mode( val & (CCR_OIX|CCR_ORA|CCR_OCE) );

        val &= 0x81A7;

        break;

    case MMUUNK1:

    	/* Note that if the high bit is set, this appears to reset the machine.

    	 * Not emulating this behaviour yet until we know why...

    	 */

    	val &= 0x00010007;

    	break;

    case QACR0:

    case QACR1:

    	val &= 0x0000001C;

    	break;

    case PMCR1:

        PMM_write_control(0, val);

        val &= 0x0000C13F;

        break;

    case PMCR2:

        PMM_write_control(1, val);

        val &= 0x0000C13F;

        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 );

    mmu_utlb_sorted_reload();

}

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;

    }

    mmu_utlb_sorted_reload();

    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)<<(LXDREAM_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-LXDREAM_PAGE_BITS));

        break;

    default: /* disabled */

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

            page_map[i] = NULL;

        break;

    }

}

/******************* Sorted TLB data structure ****************/

/*

 * mmu_utlb_sorted maintains a list of all active (valid) entries,

 * sorted by masked VPN and then ASID. Multi-hit entries are resolved 

 * ahead of time, and have -1 recorded as the corresponding PPN.

 * 

 * FIXME: Multi-hit detection doesn't pick up cases where two pages 

 * overlap due to different sizes (and don't share the same base

 * address). 

 */ 

static void mmu_utlb_sorted_reset() 

{

    mmu_utlb_entries = 0;

}

/**

 * Find an entry in the sorted table (VPN+ASID check). 

 */

static inline int mmu_utlb_sorted_find( sh4addr_t vma )

{

    int low = 0;

    int high = mmu_utlb_entries;

    uint32_t lookup = (vma & 0xFFFFFC00) + mmu_asid;

    mmu_urc++;

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

        mmu_urc = 0;

    }

    while( low != high ) {

        int posn = (high+low)>>1;

        int masked = lookup & mmu_utlb_sorted[posn].mask;

        if( mmu_utlb_sorted[posn].key < masked ) {

            low = posn+1;

        } else if( mmu_utlb_sorted[posn].key > masked ) {

            high = posn;

        } else {

            return mmu_utlb_sorted[posn].entryNo;

        }

    }

    return -1;

}

static void mmu_utlb_insert_entry( int entry )

{

    int low = 0;

    int high = mmu_utlb_entries;

    uint32_t key = (mmu_utlb[entry].vpn & mmu_utlb[entry].mask) + mmu_utlb[entry].asid;

    assert( mmu_utlb_entries < UTLB_ENTRY_COUNT );

    /* Find the insertion point */

    while( low != high ) {

        int posn = (high+low)>>1;

        if( mmu_utlb_sorted[posn].key < key ) {

            low = posn+1;

        } else if( mmu_utlb_sorted[posn].key > key ) {

            high = posn;

        } else {

            /* Exact match - multi-hit */

            mmu_utlb_sorted[posn].entryNo = -2;

            return;

        }

    } /* 0 2 4 6 */

    memmove( &mmu_utlb_sorted[low+1], &mmu_utlb_sorted[low], 

             (mmu_utlb_entries - low) * sizeof(struct utlb_sort_entry) );

    mmu_utlb_sorted[low].key = key;

    mmu_utlb_sorted[low].mask = mmu_utlb[entry].mask | 0x000000FF;

    mmu_utlb_sorted[low].entryNo = entry;

    mmu_utlb_entries++;

}

static void mmu_utlb_remove_entry( int entry )

{

    int low = 0;

    int high = mmu_utlb_entries;

    uint32_t key = (mmu_utlb[entry].vpn & mmu_utlb[entry].mask) + mmu_utlb[entry].asid;

    while( low != high ) {

        int posn = (high+low)>>1;

        if( mmu_utlb_sorted[posn].key < key ) {

            low = posn+1;

        } else if( mmu_utlb_sorted[posn].key > key ) {

            high = posn;

        } else {

            if( mmu_utlb_sorted[posn].entryNo == -2 ) {

                /* Multiple-entry recorded - rebuild the whole table minus entry */

                int i;

                mmu_utlb_entries = 0;

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

                    if( i != entry && (mmu_utlb[i].flags & TLB_VALID)  ) {

                        mmu_utlb_insert_entry(i);

                    }

                }

            } else {

                mmu_utlb_entries--;

                memmove( &mmu_utlb_sorted[posn], &mmu_utlb_sorted[posn+1],

                         (mmu_utlb_entries - posn)*sizeof(struct utlb_sort_entry) );

            }

            return;

        }

    }

    assert( 0 && "UTLB key not found!" );

}

static void mmu_utlb_sorted_reload()

{

    int i;

    mmu_utlb_entries = 0;

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

        if( mmu_utlb[i].flags & TLB_VALID ) 

            mmu_utlb_insert_entry( i );

    }

}

/* 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()

{

    if( mmu_utlb[mmu_urc].flags & TLB_VALID )

        mmu_utlb_remove_entry( mmu_urc );

    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);

    if( mmu_utlb[mmu_urc].ppn >= 0x1C000000 )

        mmu_utlb[mmu_urc].ppn |= 0xE0000000;

    if( mmu_utlb[mmu_urc].flags & TLB_VALID )

        mmu_utlb_insert_entry( mmu_urc );

}

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);

    }

    mmu_utlb_entries = 0;

}

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

int32_t FASTCALL 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 FASTCALL mmu_itlb_data_read( sh4addr_t addr )

{

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

    return (ent->ppn & 0x1FFFFC00) | ent->flags;

}

void FASTCALL 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 FASTCALL 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);

    if( ent->ppn >= 0x1C000000 )

        ent->ppn |= 0xE0000000;

}

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

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

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

int32_t FASTCALL 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 FASTCALL 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&0x1FFFFC00) | ent->flags;

    }

}

/**

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

 * lookup but ignores the valid bit.

 */

static inline int 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 int 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 FASTCALL 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];

            uint32_t old_flags = ent->flags;

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

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

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

            if( (old_flags & TLB_VALID) && !(ent->flags&TLB_VALID) ) {

                mmu_utlb_remove_entry( utlb );

            } else if( !(old_flags & TLB_VALID) && (ent->flags&TLB_VALID) ) {

                mmu_utlb_insert_entry( utlb );

            }

        }

        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)];

        if( ent->flags & TLB_VALID ) 

            mmu_utlb_remove_entry( 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);

        if( ent->flags & TLB_VALID ) 

            mmu_utlb_insert_entry( UTLB_ENTRY(addr) );

    }

}

void FASTCALL 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 {

        if( ent->flags & TLB_VALID ) 

            mmu_utlb_remove_entry( UTLB_ENTRY(addr) );

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

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

        ent->mask = get_mask_for_flags(val);

        if( mmu_utlb[mmu_urc].ppn >= 0x1C000000 )

            mmu_utlb[mmu_urc].ppn |= 0xE0000000;

        if( ent->flags & TLB_VALID ) 

            mmu_utlb_insert_entry( UTLB_ENTRY(addr) );

    }

}

/* Cache access - not implemented */

int32_t FASTCALL mmu_icache_addr_read( sh4addr_t addr )

{

    return 0; // not implemented

}

int32_t FASTCALL mmu_icache_data_read( sh4addr_t addr )

{

    return 0; // not implemented

}

int32_t FASTCALL mmu_ocache_addr_read( sh4addr_t addr )

{

    return 0; // not implemented

}

int32_t FASTCALL mmu_ocache_data_read( sh4addr_t addr )

{

    return 0; // not implemented

}

void FASTCALL mmu_icache_addr_write( sh4addr_t addr, uint32_t val )

{

}

void FASTCALL mmu_icache_data_write( sh4addr_t addr, uint32_t val )

{

}

void FASTCALL mmu_ocache_addr_write( sh4addr_t addr, uint32_t val )

{

}

void FASTCALL 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_sorted_find( 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;

}

#ifdef HAVE_FRAME_ADDRESS

sh4addr_t FASTCALL mmu_vma_to_phys_read( sh4vma_t addr, void *exc )

#else

sh4addr_t FASTCALL mmu_vma_to_phys_read( sh4vma_t addr )

#endif

{

    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_VIA(exc);

        }

    }

    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_sorted_find( addr );

    } else {

        entryNo = mmu_utlb_lookup_vpn( addr );

    }

    switch(entryNo) {

    case -1:

    MMU_TLB_READ_MISS_ERROR(addr);

    RETURN_VIA(exc);

    case -2:

    MMU_TLB_MULTI_HIT_ERROR(addr);

    RETURN_VIA(exc);

    default:

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

                !IS_SH4_PRIVMODE() ) {

            /* protection violation */

            MMU_TLB_READ_PROT_ERROR(addr);

            RETURN_VIA(exc);

        }

        /* finally generate the target address */

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

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

    }

}

#ifdef HAVE_FRAME_ADDRESS

sh4addr_t FASTCALL mmu_vma_to_phys_write( sh4vma_t addr, void *exc )

#else

sh4addr_t FASTCALL mmu_vma_to_phys_write( sh4vma_t addr )

#endif

{

    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_VIA(exc);

        }

    }

    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_sorted_find( addr );

    } else {

        entryNo = mmu_utlb_lookup_vpn( addr );

    }

    switch(entryNo) {

    case -1:

    MMU_TLB_WRITE_MISS_ERROR(addr);

    RETURN_VIA(exc);

    case -2:

    MMU_TLB_MULTI_HIT_ERROR(addr);

    RETURN_VIA(exc);

    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_VIA(exc);

        }

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

            MMU_TLB_INITIAL_WRITE_ERROR(addr);

            RETURN_VIA(exc);

        }

        /* finally generate the target address */

        sh4addr_t pma = (mmu_utlb[entryNo].ppn & mmu_utlb[entryNo].mask) |

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

        return pma;

    }

}

/**

 * Update the icache for an untranslated address

 */

static inline 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.