--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sh4/xltcache.c	Thu Aug 23 12:33:27 2007 +0000
@@ -0,0 +1,347 @@
+/**
+ * $Id: xltcache.c,v 1.1 2007-08-23 12:33:27 nkeynes Exp $
+ * 
+ * Translation cache management. This part is architecture independent.
+ *
+ * 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 "sh4/xltcache.h"
+#include "dreamcast.h"
+#include <sys/mman.h>
+#include <assert.h>
+
+#define XLAT_LUT_PAGE_BITS 12
+#define XLAT_LUT_TOTAL_BITS 28
+#define XLAT_LUT_PAGE(addr) (((addr)>>13) & 0xFFFF)
+#define XLAT_LUT_ENTRY(addr) (((addr)&0x1FFE) >> 1)
+
+#define XLAT_LUT_PAGES (1<<(XLAT_LUT_TOTAL_BITS-XLAT_LUT_PAGE_BITS))
+#define XLAT_LUT_PAGE_ENTRIES (1<<XLAT_LUT_PAGE_BITS)
+#define XLAT_LUT_PAGE_SIZE (XLAT_LUT_PAGE_ENTRIES * sizeof(void *))
+
+#define XLAT_LUT_ENTRY_EMPTY (void *)0
+#define XLAT_LUT_ENTRY_USED  (void *)1
+
+#define NEXT(block) ( (xlat_cache_block_t)&((block)->code[(block)->size]))
+#define BLOCK_FOR_CODE(code) (((xlat_cache_block_t)code)-1)
+#define IS_ENTRY_POINT(ent) (ent > XLAT_LUT_ENTRY_USED)
+#define IS_ENTRY_USED(ent) (ent != XLAT_LUT_ENTRY_EMPTY)
+
+#define MIN_BLOCK_SIZE 32
+#define MIN_TOTAL_SIZE (sizeof(struct xlat_cache_block)+MIN_BLOCK_SIZE)
+
+#define BLOCK_INACTIVE 0
+#define BLOCK_ACTIVE 1
+#define BLOCK_USED 2
+
+xlat_cache_block_t xlat_new_cache;
+xlat_cache_block_t xlat_new_cache_ptr;
+xlat_cache_block_t xlat_new_create_ptr;
+xlat_cache_block_t xlat_temp_cache;
+xlat_cache_block_t xlat_temp_cache_ptr;
+xlat_cache_block_t xlat_old_cache;
+xlat_cache_block_t xlat_old_cache_ptr;
+static void ***xlat_lut;
+static void **xlat_lut2; /* second-tier page info */
+
+void xlat_cache_init() 
+{
+    xlat_new_cache = mmap( NULL, XLAT_NEW_CACHE_SIZE, PROT_EXEC|PROT_READ|PROT_WRITE,
+			   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );
+    xlat_temp_cache = mmap( NULL, XLAT_TEMP_CACHE_SIZE, PROT_EXEC|PROT_READ|PROT_WRITE,
+			   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );
+    xlat_old_cache = mmap( NULL, XLAT_OLD_CACHE_SIZE, PROT_EXEC|PROT_READ|PROT_WRITE,
+			   MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );
+    xlat_new_cache_ptr = xlat_new_cache;
+    xlat_temp_cache_ptr = xlat_temp_cache;
+    xlat_old_cache_ptr = xlat_old_cache;
+    xlat_new_create_ptr = xlat_new_cache;
+    
+    xlat_lut = mmap( NULL, XLAT_LUT_PAGES*sizeof(void *), PROT_READ|PROT_WRITE,
+		     MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    memset( xlat_lut, 0, XLAT_LUT_PAGES*sizeof(void *) );
+
+    xlat_flush_cache();
+}
+
+/**
+ * Reset the cache structure to its default state
+ */
+void xlat_flush_cache() 
+{
+    xlat_cache_block_t tmp;
+    int i;
+    xlat_new_cache_ptr = xlat_new_cache;
+    xlat_new_cache_ptr->active = 0;
+    xlat_new_cache_ptr->size = XLAT_NEW_CACHE_SIZE - 2*sizeof(struct xlat_cache_block);
+    tmp = NEXT(xlat_new_cache_ptr);
+    tmp->active = 1;
+    tmp->size = 0;
+    xlat_temp_cache_ptr = xlat_temp_cache;
+    xlat_temp_cache_ptr->active = 0;
+    xlat_temp_cache_ptr->size = XLAT_TEMP_CACHE_SIZE - 2*sizeof(struct xlat_cache_block);
+    tmp = NEXT(xlat_temp_cache_ptr);
+    tmp->active = 1;
+    tmp->size = 0;
+    xlat_old_cache_ptr = xlat_old_cache;
+    xlat_old_cache_ptr->active = 0;
+    xlat_old_cache_ptr->size = XLAT_OLD_CACHE_SIZE - 2*sizeof(struct xlat_cache_block);
+    tmp = NEXT(xlat_old_cache_ptr);
+    tmp->active = 1;
+    tmp->size = 0;
+    for( i=0; i<XLAT_LUT_PAGES; i++ ) {
+	if( xlat_lut[i] != NULL ) {
+	    memset( xlat_lut[i], 0, XLAT_LUT_PAGE_SIZE );
+	}
+    }
+}
+
+void xlat_flush_page( sh4addr_t address )
+{
+    int i;
+    void **page = xlat_lut[XLAT_LUT_PAGE(address)];
+    for( i=0; i<XLAT_LUT_PAGE_ENTRIES; i++ ) {
+	if( IS_ENTRY_POINT(page[i]) ) {
+	    BLOCK_FOR_CODE(page[i])->active = 0;
+	}
+	page[i] = NULL;
+    }
+}
+
+void *xlat_get_code( sh4addr_t address )
+{
+    void **page = xlat_lut[XLAT_LUT_PAGE(address)];
+    if( page == NULL ) {
+	return NULL;
+    }
+    return page[XLAT_LUT_ENTRY(address)];
+}
+
+/**
+ * Cut the specified block so that it has the given size, with the remaining data
+ * forming a new free block. If the free block would be less than the minimum size,
+ * the cut is not performed.
+ * @return the next block after the (possibly cut) block.
+ */
+static inline xlat_cache_block_t xlat_cut_block( xlat_cache_block_t block, int cutsize )
+{
+    if( block->size > cutsize + MIN_TOTAL_SIZE ) {
+	int oldsize = block->size;
+	block->size = cutsize;
+	xlat_cache_block_t next = NEXT(block);
+	next->active = 0;
+	next->size = oldsize - cutsize - sizeof(struct xlat_cache_block);
+	return next;
+    } else {
+	return NEXT(block);
+    }
+}
+
+/**
+ * Promote a block in temp space (or elsewhere for that matter) to old space.
+ *
+ * @param block to promote.
+ */
+static void xlat_promote_to_old_space( xlat_cache_block_t block )
+{
+    int allocation = -sizeof(struct xlat_cache_block);
+    int size = block->size;
+    xlat_cache_block_t curr = xlat_old_cache_ptr;
+    xlat_cache_block_t start_block = curr;
+    do {
+	allocation += curr->size + sizeof(struct xlat_cache_block);
+	curr = NEXT(curr);
+	if( allocation > size ) {
+	    break; /* done */
+	}
+	if( curr->size == 0 ) { /* End-of-cache Sentinel */
+	    /* Leave what we just released as free space and start again from the
+	     * top of the cache
+	     */
+	    start_block->active = 0;
+	    start_block->size = allocation;
+	    allocation = -sizeof(struct xlat_cache_block);
+	    start_block = curr = xlat_old_cache;
+	}
+    } while(1);
+    start_block->active = 1;
+    start_block->size = allocation;
+    start_block->lut_entry = block->lut_entry;
+    *block->lut_entry = &start_block->code;
+    memcpy( start_block->code, block->code, block->size );
+    xlat_old_cache_ptr = xlat_cut_block(start_block, size );
+    if( xlat_old_cache_ptr->size == 0 ) {
+	xlat_old_cache_ptr = xlat_old_cache;
+    }
+}
+
+/**
+ * Similarly to the above method, promotes a block to temp space.
+ * TODO: Try to combine these - they're nearly identical
+ */
+void xlat_promote_to_temp_space( xlat_cache_block_t block )
+{
+    int size = block->size;
+    int allocation = -sizeof(struct xlat_cache_block);
+    xlat_cache_block_t curr = xlat_temp_cache_ptr;
+    xlat_cache_block_t start_block = curr;
+    do {
+	if( curr->active == BLOCK_USED ) {
+	    xlat_promote_to_old_space( curr );
+	}
+	allocation += curr->size + sizeof(struct xlat_cache_block);
+	curr = NEXT(curr);
+	if( allocation > size ) {
+	    break; /* done */
+	}
+	if( curr->size == 0 ) { /* End-of-cache Sentinel */
+	    /* Leave what we just released as free space and start again from the
+	     * top of the cache
+	     */
+	    start_block->active = 0;
+	    start_block->size = allocation;
+	    allocation = -sizeof(struct xlat_cache_block);
+	    start_block = curr = xlat_temp_cache;
+	}
+    } while(1);
+    start_block->active = 1;
+    start_block->size = allocation;
+    start_block->lut_entry = block->lut_entry;
+    *block->lut_entry = &start_block->code;
+    memcpy( start_block->code, block->code, block->size );
+    xlat_temp_cache_ptr = xlat_cut_block(start_block, size );
+    if( xlat_temp_cache_ptr->size == 0 ) {
+	xlat_temp_cache_ptr = xlat_temp_cache;
+    }
+    
+}
+
+/**
+ * Returns the next block in the new cache list that can be written to by the
+ * translator. If the next block is active, it is evicted first.
+ */
+xlat_cache_block_t xlat_start_block( sh4addr_t address )
+{
+    if( xlat_new_cache_ptr->size == 0 ) {
+	xlat_new_cache_ptr = xlat_new_cache;
+    }
+
+    if( xlat_new_cache_ptr->active ) {
+	xlat_promote_to_temp_space( xlat_new_cache_ptr );
+    }
+    xlat_new_create_ptr = xlat_new_cache_ptr;
+    xlat_new_create_ptr->active = 1;
+    xlat_new_cache_ptr = NEXT(xlat_new_cache_ptr);
+
+    /* Add the LUT entry for the block */
+    if( xlat_lut[XLAT_LUT_PAGE(address)] == NULL ) {
+	xlat_lut[XLAT_LUT_PAGE(address)] =
+	    mmap( NULL, XLAT_LUT_PAGE_SIZE, PROT_READ|PROT_WRITE,
+		  MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );
+	memset( xlat_lut[XLAT_LUT_PAGE(address)], 0, XLAT_LUT_PAGE_SIZE );
+    }
+
+    if( IS_ENTRY_POINT(xlat_lut[XLAT_LUT_PAGE(address)][XLAT_LUT_ENTRY(address)]) ) {
+	xlat_cache_block_t oldblock = BLOCK_FOR_CODE(xlat_lut[XLAT_LUT_PAGE(address)][XLAT_LUT_ENTRY(address)]);
+	oldblock->active = 0;
+    }
+
+    xlat_lut[XLAT_LUT_PAGE(address)][XLAT_LUT_ENTRY(address)] = 
+	&xlat_new_create_ptr->code;
+    xlat_new_create_ptr->lut_entry = xlat_lut[XLAT_LUT_PAGE(address)] + XLAT_LUT_ENTRY(address);
+    
+    return xlat_new_create_ptr;
+}
+
+xlat_cache_block_t xlat_extend_block()
+{
+    if( xlat_new_cache_ptr->size == 0 ) {
+	/* Migrate to the front of the cache to keep it contiguous */
+	xlat_new_create_ptr->active = 0;
+	char *olddata = xlat_new_create_ptr->code;
+	int oldsize = xlat_new_create_ptr->size;
+	int size = oldsize + MIN_BLOCK_SIZE; /* minimum expansion */
+	void **lut_entry = xlat_new_create_ptr->lut_entry;
+	int allocation = -sizeof(struct xlat_cache_block);
+	xlat_new_cache_ptr = xlat_new_cache;
+	do {
+	    if( xlat_new_cache_ptr->active ) {
+		xlat_promote_to_temp_space( xlat_new_cache_ptr );
+	    }
+	    allocation += xlat_new_cache_ptr->size + sizeof(struct xlat_cache_block);
+	    xlat_new_cache_ptr = NEXT(xlat_new_cache_ptr);
+	} while( allocation < size );
+	xlat_new_create_ptr = xlat_new_cache;
+	xlat_new_create_ptr->active = 1;
+	xlat_new_create_ptr->size = allocation;
+	xlat_new_create_ptr->lut_entry = lut_entry;
+	*lut_entry = &xlat_new_create_ptr->code;
+	memmove( xlat_new_create_ptr->code, olddata, oldsize );
+    } else {
+	if( xlat_new_cache_ptr->active ) {
+	    xlat_promote_to_temp_space( xlat_new_cache_ptr );
+	}
+	xlat_new_create_ptr->size += xlat_new_cache_ptr->size + sizeof(struct xlat_cache_block);
+	xlat_new_cache_ptr = NEXT(xlat_new_cache_ptr);
+    }
+    return xlat_new_create_ptr;
+
+}
+
+void xlat_commit_block( uint32_t destsize, uint32_t srcsize )
+{
+    void **ptr = xlat_new_create_ptr->lut_entry;
+    void **endptr = ptr + (srcsize>>2);
+    while( ptr < endptr ) {
+	if( *ptr == NULL ) {
+	    *ptr = XLAT_LUT_ENTRY_USED;
+	}
+	ptr++;
+    }
+
+    xlat_new_cache_ptr = xlat_cut_block( xlat_new_create_ptr, destsize );
+}
+
+void xlat_delete_block( xlat_cache_block_t block ) 
+{
+    block->active = 0;
+    *block->lut_entry = NULL;
+}
+
+void xlat_check_cache_integrity( xlat_cache_block_t cache, xlat_cache_block_t ptr, int size )
+{
+    int foundptr = 0;
+    xlat_cache_block_t tail = 
+	(xlat_cache_block_t)(((char *)cache) + size - sizeof(struct xlat_cache_block));
+
+    assert( tail->active == 1 );
+    assert( tail->size == 0 ); 
+    while( cache < tail ) {
+	assert( cache->active >= 0 && cache->active <= 2 );
+	assert( cache->size >= 0 && cache->size < size );
+	if( cache == ptr ) {
+	    foundptr = 1;
+	}
+	cache = NEXT(cache);
+    }
+    assert( cache == tail );
+    assert( foundptr == 1 );
+}
+
+void xlat_check_integrity( )
+{
+    xlat_check_cache_integrity( xlat_new_cache, xlat_new_cache_ptr, XLAT_NEW_CACHE_SIZE );
+    xlat_check_cache_integrity( xlat_temp_cache, xlat_temp_cache_ptr, XLAT_TEMP_CACHE_SIZE );
+    xlat_check_cache_integrity( xlat_old_cache, xlat_old_cache_ptr, XLAT_OLD_CACHE_SIZE );
+}