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author Olivier Galibert <galibert@pobox.com>2011-06-05 09:03:31 +0000
committer Olivier Galibert <galibert@pobox.com>2011-06-05 09:03:31 +0000
commit87a6c3f7f8886ada0537fe014d0c0f923669b33f (patch)
tree0585ac6acdf5817de72e494f2d8a3b45c81a2f2a
parent55c58f6bdf6b4c379f12fa52d4667e74c67eb77e (diff)
memory: Change the gc into a refcounter, for speed reasons. [O. Galibert]
-rw-r--r--src/emu/memory.c186
1 files changed, 131 insertions, 55 deletions
diff --git a/src/emu/memory.c b/src/emu/memory.c
index 041a2fd45e2..497cea486c0 100644
--- a/src/emu/memory.c
+++ b/src/emu/memory.c
@@ -837,7 +837,6 @@ protected:
// table population/depopulation
void populate_range_mirrored(offs_t bytestart, offs_t byteend, offs_t bytemirror, UINT8 handler);
void populate_range(offs_t bytestart, offs_t byteend, UINT8 handler);
- void depopulate_unused();
// subtable management
UINT8 subtable_alloc();
@@ -874,7 +873,30 @@ protected:
static UINT8 s_watchpoint_table[1 << LEVEL1_BITS];
private:
+ int handler_refcount[SUBTABLE_BASE-STATIC_COUNT];
+ UINT8 handler_next_free[SUBTABLE_BASE-STATIC_COUNT];
+ UINT8 handler_free;
UINT8 get_free_handler();
+ void verify_reference_counts();
+
+ void handler_ref(UINT8 entry, int count)
+ {
+ assert(entry < SUBTABLE_BASE);
+ if (entry >= STATIC_COUNT)
+ handler_refcount[entry - STATIC_COUNT] += count;
+ }
+
+ void handler_unref(UINT8 entry)
+ {
+ assert(entry < SUBTABLE_BASE);
+ if (entry >= STATIC_COUNT)
+ if (! --handler_refcount[entry - STATIC_COUNT])
+ {
+ handler(entry).deconfigure();
+ handler_next_free[entry - STATIC_COUNT] = handler_free;
+ handler_free = entry;
+ }
+ }
};
@@ -3207,6 +3229,15 @@ address_table::address_table(address_space &space, bool large)
// initialize everything to unmapped
memset(m_table, STATIC_UNMAP, 1 << LEVEL1_BITS);
+
+ // initialize the handlers freelist
+ for (int i=0; i != SUBTABLE_BASE-STATIC_COUNT-1; i++)
+ handler_next_free[i] = i+STATIC_COUNT+1;
+ handler_next_free[SUBTABLE_BASE-STATIC_COUNT-1] = STATIC_INVALID;
+ handler_free = STATIC_COUNT;
+
+ // initialize the handlers refcounts
+ memset(handler_refcount, 0, sizeof(handler_refcount));
}
@@ -3250,22 +3281,18 @@ void address_table::map_range(offs_t addrstart, offs_t addrend, offs_t addrmask,
// recompute any direct access on this space if it is a read modification
m_space.m_direct.force_update(entry);
+
+ // verify_reference_counts();
}
UINT8 address_table::get_free_handler()
{
- // scan all possible assigned entries for something unpopulated
- for (UINT8 scanentry = STATIC_COUNT; scanentry < SUBTABLE_BASE; scanentry++)
- if (!handler(scanentry).populated())
- return scanentry;
+ if (handler_free == STATIC_INVALID)
+ throw emu_fatalerror("Out of handler entries in address table");
- // if we didn't find anything, find something to depopulate and try again
- depopulate_unused();
- for (UINT8 scanentry = STATIC_COUNT; scanentry < SUBTABLE_BASE; scanentry++)
- if (!handler(scanentry).populated())
- return scanentry;
-
- throw emu_fatalerror("Out of handler entries in address table");
+ UINT8 handler = handler_free;
+ handler_free = handler_next_free[handler - STATIC_COUNT];
+ return handler;
}
@@ -3284,7 +3311,6 @@ namespace {
void address_table::setup_range(offs_t addrstart, offs_t addrend, offs_t addrmask, offs_t addrmirror, UINT64 mask, std::list<UINT32> &entries)
{
-
// convert addresses to bytes
offs_t bytestart = addrstart;
offs_t byteend = addrend;
@@ -3391,6 +3417,54 @@ void address_table::setup_range(offs_t addrstart, offs_t addrend, offs_t addrmas
m_space.m_direct.force_update(entry);
}
}
+
+ // verify_reference_counts();
+}
+
+
+//-------------------------------------------------
+// verify_reference_counts - check how much of a
+// hash we've made of things
+//-------------------------------------------------
+
+void address_table::verify_reference_counts()
+{
+ int actual_refcounts[SUBTABLE_BASE-STATIC_COUNT];
+ memset(actual_refcounts, 0, sizeof(actual_refcounts));
+
+ bool subtable_seen[256 - SUBTABLE_BASE];
+ memset(subtable_seen, 0, sizeof(subtable_seen));
+
+ for (int level1 = 0; level1 != 1 << LEVEL1_BITS; level1++)
+ {
+ UINT8 l1_entry = m_table[level1];
+ if (l1_entry >= SUBTABLE_BASE)
+ {
+ assert(m_large);
+ if (subtable_seen[l1_entry - SUBTABLE_BASE])
+ continue;
+
+ subtable_seen[l1_entry - SUBTABLE_BASE] = true;
+ const UINT8 *subtable = subtable_ptr(l1_entry);
+ for (int level2 = 0; level2 != 1 << LEVEL2_BITS; level2++)
+ {
+ UINT8 l2_entry = subtable[level2];
+ assert(l2_entry < SUBTABLE_BASE);
+ if (l2_entry >= STATIC_COUNT)
+ actual_refcounts[l2_entry - STATIC_COUNT]++;
+ }
+ }
+ else if (l1_entry >= STATIC_COUNT)
+ actual_refcounts[l1_entry - STATIC_COUNT]++;
+ }
+
+ if (memcmp(actual_refcounts, handler_refcount, sizeof(handler_refcount)))
+ {
+ logerror("Refcount failure:\n");
+ for(int i = STATIC_COUNT; i != SUBTABLE_BASE; i++)
+ logerror("%02x: %4x .. %4x\n", i, handler_refcount[i-STATIC_COUNT], actual_refcounts[i-STATIC_COUNT]);
+ throw emu_fatalerror("memory.c: refcounts are fucked.\n");
+ }
}
@@ -3419,13 +3493,23 @@ void address_table::populate_range(offs_t bytestart, offs_t byteend, UINT8 handl
// if the start and stop end within the same block, handle that
if (l1start == l1stop)
{
- memset(&subtable[l2start], handlerindex, l2stop - l2start + 1);
+ handler_ref(handlerindex, l2stop-l2start+1);
+ for (int i = l2start; i <= l2stop; i++)
+ {
+ handler_unref(subtable[i]);
+ subtable[i] = handlerindex;
+ }
subtable_close(l1start);
return;
}
// otherwise, fill until the end
- memset(&subtable[l2start], handlerindex, (1 << level2_bits()) - l2start);
+ handler_ref(handlerindex, l2mask - l2start + 1);
+ for (int i = l2start; i <= l2mask; i++)
+ {
+ handler_unref(subtable[i]);
+ subtable[i] = handlerindex;
+ }
subtable_close(l1start);
if (l1start != (offs_t)~0)
l1start++;
@@ -3437,7 +3521,12 @@ void address_table::populate_range(offs_t bytestart, offs_t byteend, UINT8 handl
UINT8 *subtable = subtable_open(l1stop);
// fill from the beginning
- memset(&subtable[0], handlerindex, l2stop + 1);
+ handler_ref(handlerindex, l2stop+1);
+ for (int i = 0; i <= l2stop; i++)
+ {
+ handler_unref(subtable[i]);
+ subtable[i] = handlerindex;
+ }
subtable_close(l1stop);
// if the start and stop end within the same block, handle that
@@ -3448,11 +3537,16 @@ void address_table::populate_range(offs_t bytestart, offs_t byteend, UINT8 handl
}
// now fill in the middle tables
+ handler_ref(handlerindex, l1stop - l1start + 1);
for (offs_t l1index = l1start; l1index <= l1stop; l1index++)
{
+ UINT8 subindex = m_table[l1index];
+
// if we have a subtable here, release it
- if (m_table[l1index] >= SUBTABLE_BASE)
- subtable_release(m_table[l1index]);
+ if (subindex >= SUBTABLE_BASE)
+ subtable_release(subindex);
+ else
+ handler_unref(subindex);
m_table[l1index] = handlerindex;
}
}
@@ -3514,10 +3608,14 @@ void address_table::populate_range_mirrored(offs_t bytestart, offs_t byteend, of
// release the subtable if the old value was a subtable
if (m_table[cur_index] >= SUBTABLE_BASE)
subtable_release(m_table[cur_index]);
+ else
+ handler_unref(m_table[cur_index]);
// reallocate the subtable if the new value is a subtable
if (m_table[prev_index] >= SUBTABLE_BASE)
subtable_realloc(m_table[prev_index]);
+ else
+ handler_ref(m_table[prev_index], 1);
// set the new value and short-circuit the mapping step
m_table[cur_index] = m_table[prev_index];
@@ -3544,41 +3642,6 @@ void address_table::populate_range_mirrored(offs_t bytestart, offs_t byteend, of
//-------------------------------------------------
-// depopulate_unused - scan the table and
-// eliminate entries that are no longer used
-//-------------------------------------------------
-
-void address_table::depopulate_unused()
-{
- bool used[SUBTABLE_BASE - STATIC_COUNT];
- memset(used, 0, sizeof(used));
-
- for (int level1 = 0; level1 != 1 << LEVEL1_BITS; level1++)
- {
- UINT8 l1_entry = m_table[level1];
- if (l1_entry >= SUBTABLE_BASE)
- {
- assert(m_large);
- const UINT8 *subtable = subtable_ptr(l1_entry);
- for (int level2 = 0; level2 != 1 << LEVEL2_BITS; level2++)
- {
- UINT8 l2_entry = subtable[level2];
- assert(l2_entry < SUBTABLE_BASE);
- if (l2_entry >= STATIC_COUNT)
- used[l2_entry - STATIC_COUNT] = true;
- }
- }
- else if (l1_entry >= STATIC_COUNT)
- used[l1_entry - STATIC_COUNT] = true;
- }
-
- for (int slot=0; slot != SUBTABLE_BASE - STATIC_COUNT; slot++)
- if (!used[slot])
- handler(slot + STATIC_COUNT).deconfigure();
-}
-
-
-//-------------------------------------------------
// derive_range - look up the entry for a memory
// range, and then compute the extent of that
// range based on the lookup tables
@@ -3826,9 +3889,15 @@ void address_table::subtable_release(UINT8 subentry)
fatalerror("Called subtable_release on a table with a usecount of 0");
// decrement the usecount and clear the checksum if we're at 0
+ // also unref the subhandlers
m_subtable[subindex].m_usecount--;
if (m_subtable[subindex].m_usecount == 0)
+ {
m_subtable[subindex].m_checksum = 0;
+ UINT8 *subtable = subtable_ptr(subentry);
+ for (int i = 0; i < (1 << LEVEL2_BITS); i++)
+ handler_unref(subtable[i]);
+ }
}
@@ -3844,8 +3913,10 @@ UINT8 *address_table::subtable_open(offs_t l1index)
// if we don't have a subtable yet, allocate a new one
if (subentry < SUBTABLE_BASE)
{
+ int size = 1 << level2_bits();
UINT8 newentry = subtable_alloc();
- memset(subtable_ptr(newentry), subentry, 1 << level2_bits());
+ handler_ref(subentry, size-1);
+ memset(subtable_ptr(newentry), subentry, size);
m_table[l1index] = newentry;
m_subtable[newentry - SUBTABLE_BASE].m_checksum = (subentry + (subentry << 8) + (subentry << 16) + (subentry << 24)) * ((1 << level2_bits())/4);
subentry = newentry;
@@ -3862,7 +3933,12 @@ UINT8 *address_table::subtable_open(offs_t l1index)
assert(subentry >= SUBTABLE_BASE);
assert(m_subtable[subentry - SUBTABLE_BASE].m_usecount > 1);
- memcpy(subtable_ptr(newentry), subtable_ptr(subentry), 1 << level2_bits());
+ int size = 1 << level2_bits();
+ UINT8 *src = subtable_ptr(subentry);
+ for(int i=0; i != size; i++)
+ handler_ref(src[i], 1);
+
+ memcpy(subtable_ptr(newentry), src, size);
subtable_release(subentry);
m_table[l1index] = newentry;
m_subtable[newentry - SUBTABLE_BASE].m_checksum = m_subtable[subentry - SUBTABLE_BASE].m_checksum;