| // -*- mode:c++ -*- |
| |
| // Copyright (c) 2003-2005 The Regents of The University of Michigan |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer; |
| // redistributions in binary form must reproduce the above copyright |
| // notice, this list of conditions and the following disclaimer in the |
| // documentation and/or other materials provided with the distribution; |
| // neither the name of the copyright holders nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| // |
| // Authors: Steve Reinhardt |
| |
| //////////////////////////////////////////////////////////////////// |
| // |
| // Control transfer instructions |
| // |
| |
| output header {{ |
| |
| /** |
| * Base class for instructions whose disassembly is not purely a |
| * function of the machine instruction (i.e., it depends on the |
| * PC). This class overrides the disassemble() method to check |
| * the PC and symbol table values before re-using a cached |
| * disassembly string. This is necessary for branches and jumps, |
| * where the disassembly string includes the target address (which |
| * may depend on the PC and/or symbol table). |
| */ |
| class PCDependentDisassembly : public AlphaStaticInst |
| { |
| protected: |
| /// Cached program counter from last disassembly |
| mutable Addr cachedPC; |
| /// Cached symbol table pointer from last disassembly |
| mutable const SymbolTable *cachedSymtab; |
| |
| /// Constructor |
| PCDependentDisassembly(const char *mnem, ExtMachInst _machInst, |
| OpClass __opClass) |
| : AlphaStaticInst(mnem, _machInst, __opClass), |
| cachedPC(0), cachedSymtab(0) |
| { |
| } |
| |
| const std::string & |
| disassemble(Addr pc, const SymbolTable *symtab) const; |
| }; |
| |
| /** |
| * Base class for branches (PC-relative control transfers), |
| * conditional or unconditional. |
| */ |
| class Branch : public PCDependentDisassembly |
| { |
| protected: |
| /// Displacement to target address (signed). |
| int32_t disp; |
| |
| /// Constructor. |
| Branch(const char *mnem, ExtMachInst _machInst, OpClass __opClass) |
| : PCDependentDisassembly(mnem, _machInst, __opClass), |
| disp(BRDISP << 2) |
| { |
| } |
| |
| AlphaISA::PCState branchTarget( |
| const AlphaISA::PCState &branchPC) const override; |
| |
| /// Explicitly import the otherwise hidden branchTarget |
| using StaticInst::branchTarget; |
| |
| std::string generateDisassembly( |
| Addr pc, const SymbolTable *symtab) const override; |
| }; |
| |
| /** |
| * Base class for jumps (register-indirect control transfers). In |
| * the Alpha ISA, these are always unconditional. |
| */ |
| class Jump : public PCDependentDisassembly |
| { |
| protected: |
| |
| /// Displacement to target address (signed). |
| int32_t disp; |
| |
| public: |
| /// Constructor |
| Jump(const char *mnem, ExtMachInst _machInst, OpClass __opClass) |
| : PCDependentDisassembly(mnem, _machInst, __opClass), |
| disp(BRDISP) |
| { |
| } |
| |
| AlphaISA::PCState branchTarget(ThreadContext *tc) const override; |
| |
| /// Explicitly import the otherwise hidden branchTarget |
| using StaticInst::branchTarget; |
| |
| std::string generateDisassembly( |
| Addr pc, const SymbolTable *symtab) const override; |
| }; |
| }}; |
| |
| output decoder {{ |
| AlphaISA::PCState |
| Branch::branchTarget(const AlphaISA::PCState &branchPC) const |
| { |
| return branchPC.pc() + 4 + disp; |
| } |
| |
| AlphaISA::PCState |
| Jump::branchTarget(ThreadContext *tc) const |
| { |
| PCState pc = tc->pcState(); |
| uint64_t Rb = tc->readIntReg(_srcRegIdx[0].index()); |
| pc.set((Rb & ~3) | (pc.pc() & 1)); |
| return pc; |
| } |
| |
| const std::string & |
| PCDependentDisassembly::disassemble(Addr pc, |
| const SymbolTable *symtab) const |
| { |
| if (!cachedDisassembly || |
| pc != cachedPC || symtab != cachedSymtab) |
| { |
| if (cachedDisassembly) |
| delete cachedDisassembly; |
| |
| cachedDisassembly = |
| new std::string(generateDisassembly(pc, symtab)); |
| cachedPC = pc; |
| cachedSymtab = symtab; |
| } |
| |
| return *cachedDisassembly; |
| } |
| |
| std::string |
| Branch::generateDisassembly(Addr pc, const SymbolTable *symtab) const |
| { |
| std::stringstream ss; |
| |
| ccprintf(ss, "%-10s ", mnemonic); |
| |
| // There's only one register arg (RA), but it could be |
| // either a source (the condition for conditional |
| // branches) or a destination (the link reg for |
| // unconditional branches) |
| if (_numSrcRegs > 0) { |
| printReg(ss, _srcRegIdx[0]); |
| ss << ","; |
| } |
| else if (_numDestRegs > 0) { |
| printReg(ss, _destRegIdx[0]); |
| ss << ","; |
| } |
| |
| #ifdef SS_COMPATIBLE_DISASSEMBLY |
| if (_numSrcRegs == 0 && _numDestRegs == 0) { |
| printReg(ss, 31); |
| ss << ","; |
| } |
| #endif |
| |
| Addr target = pc + 4 + disp; |
| |
| std::string str; |
| if (symtab && symtab->findSymbol(target, str)) |
| ss << str; |
| else |
| ccprintf(ss, "0x%x", target); |
| |
| return ss.str(); |
| } |
| |
| std::string |
| Jump::generateDisassembly(Addr pc, const SymbolTable *symtab) const |
| { |
| std::stringstream ss; |
| |
| ccprintf(ss, "%-10s ", mnemonic); |
| |
| #ifdef SS_COMPATIBLE_DISASSEMBLY |
| if (_numDestRegs == 0) { |
| printReg(ss, 31); |
| ss << ","; |
| } |
| #endif |
| |
| if (_numDestRegs > 0) { |
| printReg(ss, _destRegIdx[0]); |
| ss << ","; |
| } |
| |
| ccprintf(ss, "(r%d)", RB); |
| |
| return ss.str(); |
| } |
| }}; |
| |
| def template JumpOrBranchDecode {{ |
| return (RA == 31) |
| ? (StaticInst *)new %(class_name)s(machInst) |
| : (StaticInst *)new %(class_name)sAndLink(machInst); |
| }}; |
| |
| def format CondBranch(code) {{ |
| code = ''' |
| bool cond; |
| %(code)s; |
| if (cond) |
| NPC = NPC + disp; |
| else |
| NPC = NPC; |
| ''' % { "code" : code } |
| iop = InstObjParams(name, Name, 'Branch', code, |
| ('IsDirectControl', 'IsCondControl')) |
| header_output = BasicDeclare.subst(iop) |
| decoder_output = BasicConstructor.subst(iop) |
| decode_block = BasicDecode.subst(iop) |
| exec_output = BasicExecute.subst(iop) |
| }}; |
| |
| let {{ |
| def UncondCtrlBase(name, Name, base_class, npc_expr, flags): |
| # Declare basic control transfer w/o link (i.e. link reg is R31) |
| nolink_code = 'NPC = %s;\n' % npc_expr |
| nolink_iop = InstObjParams(name, Name, base_class, |
| nolink_code, flags) |
| header_output = BasicDeclare.subst(nolink_iop) |
| decoder_output = BasicConstructor.subst(nolink_iop) |
| exec_output = BasicExecute.subst(nolink_iop) |
| |
| # Generate declaration of '*AndLink' version, append to decls |
| link_code = 'Ra = NPC & ~3;\n' + nolink_code |
| link_iop = InstObjParams(name, Name + 'AndLink', base_class, |
| link_code, flags) |
| header_output += BasicDeclare.subst(link_iop) |
| decoder_output += BasicConstructor.subst(link_iop) |
| exec_output += BasicExecute.subst(link_iop) |
| |
| # need to use link_iop for the decode template since it is expecting |
| # the shorter version of class_name (w/o "AndLink") |
| |
| return (header_output, decoder_output, |
| JumpOrBranchDecode.subst(nolink_iop), exec_output) |
| }}; |
| |
| def format UncondBranch(*flags) {{ |
| flags += ('IsUncondControl', 'IsDirectControl') |
| (header_output, decoder_output, decode_block, exec_output) = \ |
| UncondCtrlBase(name, Name, 'Branch', 'NPC + disp', flags) |
| }}; |
| |
| def format Jump(*flags) {{ |
| flags += ('IsUncondControl', 'IsIndirectControl') |
| (header_output, decoder_output, decode_block, exec_output) = \ |
| UncondCtrlBase(name, Name, 'Jump', '(Rb & ~3) | (NPC & 1)', flags) |
| }}; |
| |
| |
