diff options
Diffstat (limited to 'src/cpu/o3/rename_map.hh')
| -rw-r--r-- | src/cpu/o3/rename_map.hh | 302 |
1 files changed, 225 insertions, 77 deletions
diff --git a/src/cpu/o3/rename_map.hh b/src/cpu/o3/rename_map.hh index 51d8db4d8..c989fb88f 100644 --- a/src/cpu/o3/rename_map.hh +++ b/src/cpu/o3/rename_map.hh @@ -1,5 +1,6 @@ /* * Copyright (c) 2004-2005 The Regents of The University of Michigan + * Copyright (c) 2013 Advanced Micro Devices, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -26,6 +27,7 @@ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * Authors: Kevin Lim + * Steve Reinhardt */ // Todo: Create destructor. @@ -42,18 +44,54 @@ #include "arch/types.hh" #include "config/the_isa.hh" #include "cpu/o3/free_list.hh" - +#include "cpu/o3/regfile.hh" +#include "cpu/reg_class.hh" + +/** + * Register rename map for a single class of registers (e.g., integer + * or floating point). Because the register class is implicitly + * determined by the rename map instance being accessed, all + * architectural register index parameters and values in this class + * are relative (e.g., %fp2 is just index 2). + */ class SimpleRenameMap { - protected: + public: + typedef TheISA::RegIndex RegIndex; + + private: + + /** The acutal arch-to-phys register map */ + std::vector<PhysRegIndex> map; + + /** + * Pointer to the free list from which new physical registers + * should be allocated in rename() + */ + SimpleFreeList *freeList; + + /** + * The architectural index of the zero register. This register is + * mapped but read-only, so we ignore attempts to rename it via + * the rename() method. If there is no such register for this map + * table, it should be set to an invalid index so that it never + * matches. + */ + RegIndex zeroReg; + public: + + SimpleRenameMap(); + + ~SimpleRenameMap() {}; + /** - * Pair of a logical register and a physical register. Tells the - * previous mapping of a logical register to a physical register. - * Used to roll back the rename map to a previous state. + * Because we have an array of rename maps (one per thread) in the CPU, + * it's awkward to initialize this object via the constructor. + * Instead, this method is used for initialization. */ - typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo; + void init(unsigned size, SimpleFreeList *_freeList, RegIndex _zeroReg); /** * Pair of a physical register and a physical register. Used to @@ -63,106 +101,216 @@ class SimpleRenameMap */ typedef std::pair<PhysRegIndex, PhysRegIndex> RenameInfo; - public: - /** Default constructor. init() must be called prior to use. */ - SimpleRenameMap() {}; - - /** Destructor. */ - ~SimpleRenameMap(); - - /** Initializes rename map with given parameters. */ - void init(unsigned _numLogicalIntRegs, - unsigned _numPhysicalIntRegs, - PhysRegIndex &_int_reg_start, + /** + * Tell rename map to get a new free physical register to remap + * the specified architectural register. + * @param arch_reg The architectural register to remap. + * @return A RenameInfo pair indicating both the new and previous + * physical registers. + */ + RenameInfo rename(RegIndex arch_reg); - unsigned _numLogicalFloatRegs, - unsigned _numPhysicalFloatRegs, - PhysRegIndex &_float_reg_start, + /** + * Look up the physical register mapped to an architectural register. + * @param arch_reg The architectural register to look up. + * @return The physical register it is currently mapped to. + */ + PhysRegIndex lookup(RegIndex arch_reg) const + { + assert(arch_reg < map.size()); + return map[arch_reg]; + } - unsigned _numMiscRegs, + /** + * Update rename map with a specific mapping. Generally used to + * roll back to old mappings on a squash. + * @param arch_reg The architectural register to remap. + * @param phys_reg The physical register to remap it to. + */ + void setEntry(RegIndex arch_reg, PhysRegIndex phys_reg) + { + map[arch_reg] = phys_reg; + } - RegIndex _intZeroReg, - RegIndex _floatZeroReg, + /** Return the number of free entries on the associated free list. */ + unsigned numFreeEntries() const { return freeList->numFreeRegs(); } +}; - int id, - bool bindRegs); - /** Sets the free list used with this rename map. */ - void setFreeList(SimpleFreeList *fl_ptr); +/** + * Unified register rename map for all classes of registers. Wraps a + * set of class-specific rename maps. Methods that do not specify a + * register class (e.g., rename()) take unified register indices, + * while methods that do specify a register class (e.g., renameInt()) + * take relative register indices. See http://gem5.org/Register_Indexing. + */ +class UnifiedRenameMap +{ + private: - //Tell rename map to get a free physical register for a given - //architected register. Not sure it should have a return value, - //but perhaps it should have some sort of fault in case there are - //no free registers. - RenameInfo rename(RegIndex arch_reg); + /** The integer register rename map */ + SimpleRenameMap intMap; - PhysRegIndex lookup(RegIndex phys_reg); + /** The floating-point register rename map */ + SimpleRenameMap floatMap; /** - * Marks the given register as ready, meaning that its value has been - * calculated and written to the register file. - * @param ready_reg The index of the physical register that is now ready. + * The register file object is used only to distinguish integer + * from floating-point physical register indices, which in turn is + * used only for assert statements that make sure the physical + * register indices that get passed in and handed out are of the + * proper class. */ - void setEntry(RegIndex arch_reg, PhysRegIndex renamed_reg); + PhysRegFile *regFile; + + public: + typedef TheISA::RegIndex RegIndex; - int numFreeEntries(); + typedef SimpleRenameMap::RenameInfo RenameInfo; - private: - /** Rename Map ID */ - int id; + /** Default constructor. init() must be called prior to use. */ + UnifiedRenameMap() {}; - /** Number of logical integer registers. */ - int numLogicalIntRegs; + /** Destructor. */ + ~UnifiedRenameMap() {}; - /** Number of physical integer registers. */ - int numPhysicalIntRegs; + /** Initializes rename map with given parameters. */ + void init(PhysRegFile *_regFile, + RegIndex _intZeroReg, + RegIndex _floatZeroReg, + UnifiedFreeList *freeList); - /** Number of logical floating point registers. */ - int numLogicalFloatRegs; + /** + * Tell rename map to get a new free physical register to remap + * the specified architectural register. This version takes a + * unified flattened architectural register index and calls the + * appropriate class-specific rename table. + * @param arch_reg The unified architectural register index to remap. + * @return A RenameInfo pair indicating both the new and previous + * physical registers. + */ + RenameInfo rename(RegIndex arch_reg); - /** Number of physical floating point registers. */ - int numPhysicalFloatRegs; + /** + * Perform rename() on an integer register, given a relative + * integer register index. + */ + RenameInfo renameInt(RegIndex rel_arch_reg) + { + RenameInfo info = intMap.rename(rel_arch_reg); + assert(regFile->isIntPhysReg(info.first)); + return info; + } + + /** + * Perform rename() on a floating-point register, given a relative + * floating-point register index. + */ + RenameInfo renameFloat(RegIndex rel_arch_reg) + { + RenameInfo info = floatMap.rename(rel_arch_reg); + assert(regFile->isFloatPhysReg(info.first)); + return info; + } - /** Number of miscellaneous registers. */ - int numMiscRegs; + /** + * Perform rename() on a misc register, given a relative + * misc register index. + */ + RenameInfo renameMisc(RegIndex rel_arch_reg) + { + // misc regs aren't really renamed, just remapped + PhysRegIndex phys_reg = lookupMisc(rel_arch_reg); + // Set the previous register to the same register; mainly it must be + // known that the prev reg was outside the range of normal registers + // so the free list can avoid adding it. + return RenameInfo(phys_reg, phys_reg); + } - /** Number of logical integer + float registers. */ - int numLogicalRegs; - /** Number of physical integer + float registers. */ - int numPhysicalRegs; + /** + * Look up the physical register mapped to an architectural register. + * This version takes a unified flattened architectural register index + * and calls the appropriate class-specific rename table. + * @param arch_reg The unified architectural register to look up. + * @return The physical register it is currently mapped to. + */ + PhysRegIndex lookup(RegIndex arch_reg) const; - /** The integer zero register. This implementation assumes it is always - * zero and never can be anything else. + /** + * Perform lookup() on an integer register, given a relative + * integer register index. */ - RegIndex intZeroReg; + PhysRegIndex lookupInt(RegIndex rel_arch_reg) const + { + PhysRegIndex phys_reg = intMap.lookup(rel_arch_reg); + assert(regFile->isIntPhysReg(phys_reg)); + return phys_reg; + } - /** The floating point zero register. This implementation assumes it is - * always zero and never can be anything else. + /** + * Perform lookup() on a floating-point register, given a relative + * floating-point register index. */ - RegIndex floatZeroReg; + PhysRegIndex lookupFloat(RegIndex rel_arch_reg) const + { + PhysRegIndex phys_reg = floatMap.lookup(rel_arch_reg); + assert(regFile->isFloatPhysReg(phys_reg)); + return phys_reg; + } - class RenameEntry + /** + * Perform lookup() on a misc register, given a relative + * misc register index. + */ + PhysRegIndex lookupMisc(RegIndex rel_arch_reg) const { - public: - PhysRegIndex physical_reg; - bool valid; + // misc regs aren't really renamed, just given an index + // beyond the range of actual physical registers + PhysRegIndex phys_reg = rel_arch_reg + regFile->totalNumPhysRegs(); + return phys_reg; + } - RenameEntry() - : physical_reg(0), valid(false) - { } - }; + /** + * Update rename map with a specific mapping. Generally used to + * roll back to old mappings on a squash. This version takes a + * unified flattened architectural register index and calls the + * appropriate class-specific rename table. + * @param arch_reg The unified architectural register to remap. + * @param phys_reg The physical register to remap it to. + */ + void setEntry(RegIndex arch_reg, PhysRegIndex phys_reg); - private: - /** Integer rename map. */ - std::vector<RenameEntry> intRenameMap; + /** + * Perform setEntry() on an integer register, given a relative + * integer register index. + */ + void setIntEntry(RegIndex arch_reg, PhysRegIndex phys_reg) + { + assert(regFile->isIntPhysReg(phys_reg)); + intMap.setEntry(arch_reg, phys_reg); + } - /** Floating point rename map. */ - std::vector<RenameEntry> floatRenameMap; + /** + * Perform setEntry() on a floating-point register, given a relative + * floating-point register index. + */ + void setFloatEntry(RegIndex arch_reg, PhysRegIndex phys_reg) + { + assert(regFile->isFloatPhysReg(phys_reg)); + floatMap.setEntry(arch_reg, phys_reg); + } - private: - /** Free list interface. */ - SimpleFreeList *freeList; + /** + * Return the minimum number of free entries across all of the + * register classes. The minimum is used so we guarantee that + * this number of entries is available regardless of which class + * of registers is requested. + */ + unsigned numFreeEntries() const + { + return std::min(intMap.numFreeEntries(), floatMap.numFreeEntries()); + } }; #endif //__CPU_O3_RENAME_MAP_HH__ |