// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
drcbeut.c
Utility functions for dynamic recompiling backends.
***************************************************************************/
#include "emu.h"
#include "drcbeut.h"
using namespace uml;
//**************************************************************************
// DEBUGGING
//**************************************************************************
#define LOG_RECOVER (0)
//**************************************************************************
// DRC HASH TABLE
//**************************************************************************
//-------------------------------------------------
// drc_hash_table - constructor
//-------------------------------------------------
drc_hash_table::drc_hash_table(drc_cache &cache, uint32_t modes, uint8_t addrbits, uint8_t ignorebits)
: m_cache(cache),
m_modes(modes),
m_nocodeptr(nullptr),
m_l1bits((addrbits - ignorebits) / 2),
m_l2bits((addrbits - ignorebits) - m_l1bits),
m_l1shift(ignorebits + m_l2bits),
m_l2shift(ignorebits),
m_l1mask((1 << m_l1bits) - 1),
m_l2mask((1 << m_l2bits) - 1),
m_base(reinterpret_cast<drccodeptr ***>(cache.alloc(modes * sizeof(**m_base)))),
m_emptyl1(nullptr),
m_emptyl2(nullptr)
{
reset();
}
//-------------------------------------------------
// reset - flush existing hash tables and create
// new ones
//-------------------------------------------------
bool drc_hash_table::reset()
{
// allocate an empty l2 hash table
m_emptyl2 = (drccodeptr *)m_cache.alloc_temporary(sizeof(drccodeptr) << m_l2bits);
if (m_emptyl2 == nullptr)
return false;
// populate it with pointers to the recompile_exit code
for (int entry = 0; entry < (1 << m_l2bits); entry++)
m_emptyl2[entry] = m_nocodeptr;
// allocate an empty l1 hash table
m_emptyl1 = (drccodeptr **)m_cache.alloc_temporary(sizeof(drccodeptr *) << m_l1bits);
if (m_emptyl1 == nullptr)
return false;
// populate it with pointers to the empty l2 table
for (int entry = 0; entry < (1 << m_l1bits); entry++)
m_emptyl1[entry] = m_emptyl2;
// reset the hash tables
for (int modenum = 0; modenum < m_modes; modenum++)
m_base[modenum] = m_emptyl1;
return true;
}
//-------------------------------------------------
// block_begin - note the beginning of a block
//-------------------------------------------------
void drc_hash_table::block_begin(drcuml_block &block, const uml::instruction *instlist, uint32_t numinst)
{
// before generating code, pre-allocate any hash entries; we do this by setting dummy hash values
for (int inum = 0; inum < numinst; inum++)
{
const uml::instruction &inst = instlist[inum];
// if the opcode is a hash, verify that it makes sense and then set a nullptr entry
if (inst.opcode() == OP_HASH)
{
assert(inst.numparams() == 2);
// if we fail to allocate, we must abort the block
if (!set_codeptr(inst.param(0).immediate(), inst.param(1).immediate(), nullptr))
block.abort();
}
// if the opcode is a hashjmp to a fixed location, make sure we preallocate the tables
if (inst.opcode() == OP_HASHJMP && inst.param(0).is_immediate() && inst.param(1).is_immediate())
{
// if we fail to allocate, we must abort the block
drccodeptr code = get_codeptr(inst.param(0).immediate(), inst.param(1).immediate());
if (!set_codeptr(inst.param(0).immediate(), inst.param(1).immediate(), code))
block.abort();
}
}
}
//-------------------------------------------------
// block_end - note the end of a block
//-------------------------------------------------
void drc_hash_table::block_end(drcuml_block &block)
{
// nothing to do here, yet
}
//-------------------------------------------------
// set_default_codeptr - change the default
// codeptr
//-------------------------------------------------
void drc_hash_table::set_default_codeptr(drccodeptr nocodeptr)
{
// nothing to do if the same
drccodeptr old = m_nocodeptr;
if (old == nocodeptr)
return;
m_nocodeptr = nocodeptr;
// update the empty L2 table first
for (int l2entry = 0; l2entry < (1 << m_l2bits); l2entry++)
m_emptyl2[l2entry] = nocodeptr;
// now scan all existing hashtables for entries
for (int modenum = 0; modenum < m_modes; modenum++)
if (m_base[modenum] != m_emptyl1)
for (int l1entry = 0; l1entry < (1 << m_l1bits); l1entry++)
if (m_base[modenum][l1entry] != m_emptyl2)
for (int l2entry = 0; l2entry < (1 << m_l2bits); l2entry++)
if (m_base[modenum][l1entry][l2entry] == old)
m_base[modenum][l1entry][l2entry] = nocodeptr;
}
//-------------------------------------------------
// set_codeptr - set the codeptr for the given
// mode/pc
//-------------------------------------------------
bool drc_hash_table::set_codeptr(uint32_t mode, uint32_t pc, drccodeptr code)
{
// copy-on-write for the l1 hash table
assert(mode < m_modes);
if (m_base[mode] == m_emptyl1)
{
drccodeptr **newtable = (drccodeptr **)m_cache.alloc_temporary(sizeof(drccodeptr *) << m_l1bits);
if (newtable == nullptr)
return false;
memcpy(newtable, m_emptyl1, sizeof(drccodeptr *) << m_l1bits);
m_base[mode] = newtable;
}
// copy-on-write for the l2 hash table
uint32_t l1 = (pc >> m_l1shift) & m_l1mask;
if (m_base[mode][l1] == m_emptyl2)
{
drccodeptr *newtable = (drccodeptr *)m_cache.alloc_temporary(sizeof(drccodeptr) << m_l2bits);
if (newtable == nullptr)
return false;
memcpy(newtable, m_emptyl2, sizeof(drccodeptr) << m_l2bits);
m_base[mode][l1] = newtable;
}
// set the new entry
uint32_t l2 = (pc >> m_l2shift) & m_l2mask;
m_base[mode][l1][l2] = code;
return true;
}
//**************************************************************************
// DRC MAP VARIABLES
//**************************************************************************
//-------------------------------------------------
// drc_map_variables - constructor
//-------------------------------------------------
drc_map_variables::drc_map_variables(drc_cache &cache, uint64_t uniquevalue)
: m_cache(cache),
m_uniquevalue(uniquevalue)
{
memset(m_mapvalue, 0, sizeof(m_mapvalue));
}
//-------------------------------------------------
// ~drc_map_variables - destructor
//-------------------------------------------------
drc_map_variables::~drc_map_variables()
{
// must detach all items from the entry list so that the list object
// doesn't try to free them on exit
m_entry_list.detach_all();
}
//-------------------------------------------------
// block_begin - note the beginning of a block
//-------------------------------------------------
void drc_map_variables::block_begin(drcuml_block &block)
{
// release any remaining live entries
map_entry *entry;
while ((entry = m_entry_list.detach_head()) != nullptr)
m_cache.dealloc(entry, sizeof(*entry));
// reset the variable values
memset(m_mapvalue, 0, sizeof(m_mapvalue));
}
//-------------------------------------------------
// block_end - note the end of a block
//-------------------------------------------------
void drc_map_variables::block_end(drcuml_block &block)
{
// only process if we have data
if (m_entry_list.first() == nullptr)
return;
// begin "code generation" aligned to an 8-byte boundary
drccodeptr *top = m_cache.begin_codegen(sizeof(uint64_t) + sizeof(uint32_t) + 2 * sizeof(uint32_t) * m_entry_list.count());
if (top == nullptr)
block.abort();
uint32_t *dest = (uint32_t *)(((uintptr_t)*top + 7) & ~7);
// store the cookie first
*(uint64_t *)dest = m_uniquevalue;
dest += 2;
// get the pointer to the first item and store an initial backwards offset
drccodeptr lastptr = m_entry_list.first()->m_codeptr;
*dest = (drccodeptr)dest - lastptr;
dest++;
// now iterate over entries and store them
uint32_t curvalue[MAPVAR_COUNT] = { 0 };
bool changed[MAPVAR_COUNT] = { false };
for (map_entry *entry = m_entry_list.first(); entry != nullptr; entry = entry->next())
{
// update the current value of the variable and detect changes
if (curvalue[entry->m_mapvar] != entry->m_newval)
{
curvalue[entry->m_mapvar] = entry->m_newval;
changed[entry->m_mapvar] = true;
}
// if the next code pointer is different, or if we're at the end, flush changes
if (entry->next() == nullptr || entry->next()->m_codeptr != entry->m_codeptr)
{
// build a mask of changed variables
int numchanged = 0;
uint32_t varmask = 0;
for (int varnum = 0; varnum < ARRAY_LENGTH(changed); varnum++)
if (changed[varnum])
{
changed[varnum] = false;
varmask |= 1 << varnum;
numchanged++;
}
// if nothing really changed, skip it
if (numchanged == 0)
continue;
// first word is a code delta plus mask of changed variables
uint32_t codedelta = entry->m_codeptr - lastptr;
while (codedelta > 0xffff)
{
*dest++ = 0xffff << 16;
codedelta -= 0xffff;
}
*dest++ = (codedelta << 16) | (varmask << 4) | numchanged;
// now output updated variable values
for (int varnum = 0; varnum < ARRAY_LENGTH(changed); varnum++)
if ((varmask >> varnum) & 1)
*dest++ = curvalue[varnum];
// remember our lastptr
lastptr = entry->m_codeptr;
}
}
// add a terminator
*dest++ = 0;
// complete codegen
*top = (drccodeptr)dest;
m_cache.end_codegen();
}
//-------------------------------------------------
// set_value - set a map value for the given
// code pointer
//-------------------------------------------------
void drc_map_variables::set_value(drccodeptr codebase, uint32_t mapvar, uint32_t newvalue)
{
assert(mapvar >= MAPVAR_M0 && mapvar < MAPVAR_END);
// if this value isn't different, skip it
if (m_mapvalue[mapvar - MAPVAR_M0] == newvalue)
return;
// allocate a new entry and fill it in
map_entry *entry = (map_entry *)m_cache.alloc(sizeof(*entry));
entry->m_next = nullptr;
entry->m_codeptr = codebase;
entry->m_mapvar = mapvar - MAPVAR_M0;
entry->m_newval = newvalue;
// hook us into the end of the list
m_entry_list.append(*entry);
// update our state in the table as well
m_mapvalue[mapvar - MAPVAR_M0] = newvalue;
}
//-------------------------------------------------
// get_value - return a map value for the given
// code pointer
//-------------------------------------------------
uint32_t drc_map_variables::get_value(drccodeptr codebase, uint32_t mapvar) const
{
assert(mapvar >= MAPVAR_M0 && mapvar < MAPVAR_END);
mapvar -= MAPVAR_M0;
// get an aligned pointer to start scanning
uint64_t *curscan = (uint64_t *)(((uintptr_t)codebase | 7) + 1);
uint64_t *endscan = (uint64_t *)m_cache.top();
// look for the signature
while (curscan < endscan && *curscan++ != m_uniquevalue) {};
if (curscan >= endscan)
return 0;
// switch to 32-bit pointers for processing the rest
uint32_t *data = (uint32_t *)curscan;
// first get the 32-bit starting offset to the code
drccodeptr curcode = (drccodeptr)data - *data;
data++;
// now loop until we advance past our target
uint32_t varmask = 0x10 << mapvar;
uint32_t result = 0;
while (true)
{
// a 0 is a terminator
uint32_t controlword = *data++;
if (controlword == 0)
break;
// update the codeptr; if this puts us past the end, we're done
curcode += (controlword >> 16) & 0xffff;
if (curcode > codebase)
break;
// if our mapvar has changed, process this word
if ((controlword & varmask) != 0)
{
// count how many words precede the one we care about
int dataoffs = 0;
for (uint32_t skipmask = (controlword & (varmask - 1)) >> 4; skipmask != 0; skipmask = skipmask & (skipmask - 1))
dataoffs++;
// fetch the one we want
result = data[dataoffs];
}
// low 4 bits contain the total number of words of data
data += controlword & 0x0f;
}
if (LOG_RECOVER)
printf("recover %d @ %p = %08X\n", mapvar, codebase, result);
return result;
}
uint32_t drc_map_variables::static_get_value(drc_map_variables &map, drccodeptr codebase, uint32_t mapvar)
{
return map.get_value(codebase, mapvar);
}
//-------------------------------------------------
// get_last_value - return the most recently set
// map value
//-------------------------------------------------
uint32_t drc_map_variables::get_last_value(uint32_t mapvar)
{
assert(mapvar >= MAPVAR_M0 && mapvar < MAPVAR_END);
return m_mapvalue[mapvar - MAPVAR_M0];
}
//**************************************************************************
// DRC LABEL LIST
//**************************************************************************
//-------------------------------------------------
// drc_label_list - constructor
//-------------------------------------------------
drc_label_list::drc_label_list(drc_cache &cache)
: m_cache(cache),
m_oob_callback_delegate(&drc_label_list::oob_callback, this)
{
}
//-------------------------------------------------
// ~drc_label_list - destructor
//-------------------------------------------------
drc_label_list::~drc_label_list()
{
// must detach all items from the entry list so that the list object
// doesn't try to free them on exit
m_list.detach_all();
}
//-------------------------------------------------
// block_begin - note the beginning of a block
//-------------------------------------------------
void drc_label_list::block_begin(drcuml_block &block)
{
// make sure the label list is clear, but don't fatalerror
reset(false);
}
//-------------------------------------------------
// block_end - note the end of a block
//-------------------------------------------------
void drc_label_list::block_end(drcuml_block &block)
{
// can't free until the cache is clean of our OOB requests
assert(!m_cache.generating_code());
// free all of the pending fixup requests
label_fixup *fixup;
while ((fixup = m_fixup_list.detach_head()) != nullptr)
m_cache.dealloc(fixup, sizeof(*fixup));
// make sure the label list is clear, and fatalerror if we missed anything
reset(true);
}
//-------------------------------------------------
// get_codeptr - find or allocate a new label;
// returns nullptr and requests an OOB callback if
// undefined
//-------------------------------------------------
drccodeptr drc_label_list::get_codeptr(uml::code_label label, drc_label_fixup_delegate callback, void *param)
{
label_entry *curlabel = find_or_allocate(label);
// if no code pointer, request an OOB callback
if (curlabel->m_codeptr == nullptr && !callback.isnull())
{
label_fixup *fixup = reinterpret_cast<label_fixup *>(m_cache.alloc(sizeof(*fixup)));
fixup->m_callback = callback;
fixup->m_label = curlabel;
m_fixup_list.append(*fixup);
m_cache.request_oob_codegen(m_oob_callback_delegate, fixup, param);
}
return curlabel->m_codeptr;
}
//-------------------------------------------------
// set_codeptr - set the pointer to a new label
//-------------------------------------------------
void drc_label_list::set_codeptr(uml::code_label label, drccodeptr codeptr)
{
// set the code pointer
label_entry *curlabel = find_or_allocate(label);
assert(curlabel->m_codeptr == nullptr);
curlabel->m_codeptr = codeptr;
}
//-------------------------------------------------
// reset - reset a label list (add all entries to
// the free list)
//-------------------------------------------------
void drc_label_list::reset(bool fatal_on_leftovers)
{
// loop until out of labels
label_entry *curlabel;
while ((curlabel = m_list.detach_head()) != nullptr)
{
// fatal if we were a leftover
if (fatal_on_leftovers && curlabel->m_codeptr == nullptr)
fatalerror("Label %08X never defined!\n", curlabel->m_label.label());
// free the label
m_cache.dealloc(curlabel, sizeof(*curlabel));
}
}
//-------------------------------------------------
// find_or_allocate - look up a label and
// allocate a new one if not found
//-------------------------------------------------
drc_label_list::label_entry *drc_label_list::find_or_allocate(uml::code_label label)
{
// find the label, or else allocate a new one
label_entry *curlabel;
for (curlabel = m_list.first(); curlabel != nullptr; curlabel = curlabel->next())
if (curlabel->m_label == label)
break;
// if none found, allocate
if (curlabel == nullptr)
{
curlabel = (label_entry *)m_cache.alloc(sizeof(*curlabel));
curlabel->m_label = label;
curlabel->m_codeptr = nullptr;
m_list.append(*curlabel);
}
return curlabel;
}
//-------------------------------------------------
// oob_callback - out-of-band codegen callback
// for labels
//-------------------------------------------------
void drc_label_list::oob_callback(drccodeptr *codeptr, void *param1, void *param2)
{
label_fixup *fixup = reinterpret_cast<label_fixup *>(param1);
fixup->m_callback(param2, fixup->m_label->m_codeptr);
}