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ISA: Make the decode function part of the ISA's decoder.

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This commit is contained in:
Gabe Black
2012-05-25 00:55:24 -07:00
parent 276f3e9535
commit eae1e97fb0
30 changed files with 423 additions and 161 deletions
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84
src/cpu/decode_cache.hh
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@@ -37,9 +37,11 @@
#include "config/the_isa.hh"
#include "cpu/static_inst.hh"
typedef StaticInstPtr (*DecodeInstFunc)(TheISA::ExtMachInst);
namespace TheISA
{
class Decoder;
}
template <DecodeInstFunc decodeInstFunc>
class DecodeCache
{
private:
@@ -63,92 +65,26 @@ class DecodeCache
/// Update the small cache of recent lookups.
/// @param recentest The most recent result;
void
update(PageIt recentest)
{
recent[1] = recent[0];
recent[0] = recentest;
}
void
addPage(Addr addr, DecodePage *page)
{
Addr page_addr = addr & ~(TheISA::PageBytes - 1);
typename PageMap::value_type to_insert(page_addr, page);
update(pageMap.insert(to_insert).first);
}
void update(PageIt recentest);
void addPage(Addr addr, DecodePage *page);
public:
/// Constructor
DecodePages()
{
recent[0] = recent[1] = pageMap.end();
}
DecodePages();
/// Attempt to find the DecodePage which goes with a particular
/// address. First check the small cache of recent results, then
/// actually look in the hash_map.
/// @param addr The address to look up.
DecodePage *
getPage(Addr addr)
{
Addr page_addr = addr & ~(TheISA::PageBytes - 1);
// Check against recent lookups.
if (recent[0] != pageMap.end()) {
if (recent[0]->first == page_addr)
return recent[0]->second;
if (recent[1] != pageMap.end() &&
recent[1]->first == page_addr) {
update(recent[1]);
// recent[1] has just become recent[0].
return recent[0]->second;
}
}
// Actually look in the has_map.
PageIt it = pageMap.find(page_addr);
if (it != pageMap.end()) {
update(it);
return it->second;
}
// Didn't find an existing page, so add a new one.
DecodePage *newPage = new DecodePage;
addPage(page_addr, newPage);
return newPage;
}
DecodePage *getPage(Addr addr);
} decodePages;
public:
/// Decode a machine instruction.
/// @param mach_inst The binary instruction to decode.
/// @retval A pointer to the corresponding StaticInst object.
StaticInstPtr
decode(ExtMachInst mach_inst, Addr addr)
{
// Try to find a matching address based table of instructions.
DecodePage *page = decodePages.getPage(addr);
// Use the table to decode the instruction. It will fall back to other
// mechanisms if it needs to.
Addr offset = addr & (TheISA::PageBytes - 1);
StaticInstPtr si = page->insts[offset];
if (si && (si->machInst == mach_inst))
return si;
InstMap::iterator iter = instMap.find(mach_inst);
if (iter != instMap.end()) {
si = iter->second;
page->insts[offset] = si;
return si;
}
si = decodeInstFunc(mach_inst);
instMap[mach_inst] = si;
page->insts[offset] = si;
return si;
}
StaticInstPtr decode(TheISA::Decoder * const decoder,
ExtMachInst mach_inst, Addr addr);
};
#endif // __CPU_DECODE_CACHE_HH__