decoder.isa

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· ISA 代码 · 共 1,399 行 · 第 1/5 页

////////////////////////////////////////////////////////////////////
//
// The actual decoder specification
//

decode OP default Unknown::unknown()
{
    0x0: decode OP2
    {
        //Throw an illegal instruction acception
        0x0: Trap::illtrap({{fault = new IllegalInstruction;}});
        format BranchN
        {
            //bpcc
            0x1: decode COND2
            {
                //Branch Always
                0x8: bpa(19, annul_code={{
                                 NPC = xc->readPC() + disp;
                                 NNPC = NPC + 4;
                             }});
                //Branch Never
                0x0: bpn(19, {{;}},
                             annul_code={{
                                 NNPC = NPC + 8;
                                 NPC = NPC + 4;
                             }});
                default: decode BPCC
                {
                    0x0: bpcci(19, test={{passesCondition(Ccr<3:0>, COND2)}});
                    0x2: bpccx(19, test={{passesCondition(Ccr<7:4>, COND2)}});
                }
            }
            //bicc
            0x2: decode COND2
            {
                //Branch Always
                0x8: ba(22, annul_code={{
                                NPC = xc->readPC() + disp;
                                NNPC = NPC + 4;
                            }});
                //Branch Never
                0x0: bn(22, {{;}},
                            annul_code={{
                                NNPC = NPC + 8;
                                NPC = NPC + 4;
                            }});
                default: bicc(22, test={{passesCondition(Ccr<3:0>, COND2)}});
            }
        }
        0x3: decode RCOND2
        {
            format BranchSplit
            {
                0x1: bpreq(test={{Rs1.sdw == 0}});
                0x2: bprle(test={{Rs1.sdw <= 0}});
                0x3: bprl(test={{Rs1.sdw < 0}});
                0x5: bprne(test={{Rs1.sdw != 0}});
                0x6: bprg(test={{Rs1.sdw > 0}});
                0x7: bprge(test={{Rs1.sdw >= 0}});
            }
        }
        //SETHI (or NOP if rd == 0 and imm == 0)
        0x4: SetHi::sethi({{Rd.udw = imm;}});
        //fbpfcc
        0x5: decode COND2 {
            format BranchN {
                //Branch Always
                0x8: fbpa(22, annul_code={{
                                  NPC = xc->readPC() + disp;
                                  NNPC = NPC + 4;
                              }});
                //Branch Never
                0x0: fbpn(22, {{;}},
                             annul_code={{
                                 NNPC = NPC + 8;
                                 NPC = NPC + 4;
                             }});
                default: decode BPCC {
                    0x0: fbpfcc0(19, test=
                                 {{passesFpCondition(Fsr<11:10>, COND2)}});
                    0x1: fbpfcc1(19, test=
                                 {{passesFpCondition(Fsr<33:32>, COND2)}});
                    0x2: fbpfcc2(19, test=
                                 {{passesFpCondition(Fsr<35:34>, COND2)}});
                    0x3: fbpfcc3(19, test=
                                 {{passesFpCondition(Fsr<37:36>, COND2)}});
                }
            }
        }
        //fbfcc
        0x6: decode COND2 {
            format BranchN {
                //Branch Always
                0x8: fba(22, annul_code={{
                                 NPC = xc->readPC() + disp;
                                 NNPC = NPC + 4;
                             }});
                //Branch Never
                0x0: fbn(22, {{;}},
                             annul_code={{
                                 NNPC = NPC + 8;
                                 NPC = NPC + 4;
                             }});
                default: fbfcc(22, test=
                               {{passesFpCondition(Fsr<11:10>, COND2)}});
            }
        }
    }
    0x1: BranchN::call(30, {{
            if (Pstate<3:>)
                R15 = (xc->readPC())<31:0>;
            else
                R15 = xc->readPC();
            NNPC = R15 + disp;
    }});
    0x2: decode OP3 {
        format IntOp {
            0x00: add({{Rd = Rs1.sdw + Rs2_or_imm13;}});
            0x01: and({{Rd = Rs1.sdw & Rs2_or_imm13;}});
            0x02: or({{Rd = Rs1.sdw | Rs2_or_imm13;}});
            0x03: xor({{Rd = Rs1.sdw ^ Rs2_or_imm13;}});
            0x04: sub({{Rd = Rs1.sdw - Rs2_or_imm13;}});
            0x05: andn({{Rd = Rs1.sdw & ~Rs2_or_imm13;}});
            0x06: orn({{Rd = Rs1.sdw | ~Rs2_or_imm13;}});
            0x07: xnor({{Rd = ~(Rs1.sdw ^ Rs2_or_imm13);}});
            0x08: addc({{Rd = Rs1.sdw + Rs2_or_imm13 + Ccr<0:0>;}});
            0x09: mulx({{Rd = Rs1.sdw * Rs2_or_imm13;}});
            0x0A: umul({{
                Rd = Rs1.udw<31:0> * Rs2_or_imm13<31:0>;
                Y = Rd<63:32>;
            }});
            0x0B: smul({{
                Rd.sdw = sext<32>(Rs1.sdw<31:0>) * sext<32>(Rs2_or_imm13<31:0>);
                Y = Rd.sdw<63:32>;
            }});
            0x0C: subc({{Rd.sdw = Rs1.sdw + (~Rs2_or_imm13) + 1 - Ccr<0:0>}});
            0x0D: udivx({{
                if(Rs2_or_imm13 == 0) fault = new DivisionByZero;
                else Rd.udw = Rs1.udw / Rs2_or_imm13;
            }});
            0x0E: udiv({{
                if(Rs2_or_imm13 == 0) fault = new DivisionByZero;
                else
                {
                    Rd.udw = ((Y << 32) | Rs1.udw<31:0>) / Rs2_or_imm13;
                    if(Rd.udw >> 32 != 0)
                        Rd.udw = 0xFFFFFFFF;
                }
            }});
            0x0F: sdiv({{
                if(Rs2_or_imm13.sdw == 0)
                    fault = new DivisionByZero;
                else
                {
                    Rd.udw = ((int64_t)((Y << 32) | Rs1.sdw<31:0>)) / Rs2_or_imm13.sdw;
                    if((int64_t)Rd.udw >= std::numeric_limits<int32_t>::max())
                        Rd.udw = 0x7FFFFFFF;
                    else if((int64_t)Rd.udw <= std::numeric_limits<int32_t>::min())
                        Rd.udw = ULL(0xFFFFFFFF80000000);
                }
            }});
        }
        format IntOpCc {
            0x10: addcc({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = op1 + op2;
                }});
            0x11: IntOpCcRes::andcc({{Rd = Rs1 & Rs2_or_imm13;}});
            0x12: IntOpCcRes::orcc({{Rd = Rs1 | Rs2_or_imm13;}});
            0x13: IntOpCcRes::xorcc({{Rd = Rs1 ^ Rs2_or_imm13;}});
            0x14: subcc({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = op1 - op2;
                }}, sub=True);
            0x15: IntOpCcRes::andncc({{Rd = Rs1 & ~Rs2_or_imm13;}});
            0x16: IntOpCcRes::orncc({{Rd = Rs1 | ~Rs2_or_imm13;}});
            0x17: IntOpCcRes::xnorcc({{Rd = ~(Rs1 ^ Rs2_or_imm13);}});
            0x18: addccc({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = op1 + op2 + Ccr<0:>;
                }});
            0x1A: IntOpCcRes::umulcc({{
                uint64_t resTemp;
                Rd = resTemp = Rs1.udw<31:0> * Rs2_or_imm13.udw<31:0>;
                Y = resTemp<63:32>;}});
            0x1B: IntOpCcRes::smulcc({{
                int64_t resTemp;
                Rd = resTemp = sext<32>(Rs1.sdw<31:0>) * sext<32>(Rs2_or_imm13<31:0>);
                Y = resTemp<63:32>;}});
            0x1C: subccc({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = op1 - op2 - Ccr<0:>;
                }}, sub=True);
            0x1D: IntOpCcRes::udivxcc({{
                if(Rs2_or_imm13.udw == 0) fault = new DivisionByZero;
                else Rd = Rs1.udw / Rs2_or_imm13.udw;}});
            0x1E: IntOpCcRes::udivcc({{
                    uint32_t resTemp, val2 = Rs2_or_imm13.udw;
                    int32_t overflow = 0;
                    if(val2 == 0) fault = new DivisionByZero;
                    else
                    {
                        resTemp = (uint64_t)((Y << 32) | Rs1.udw<31:0>) / val2;
                        overflow = (resTemp<63:32> != 0);
                        if(overflow) Rd = resTemp = 0xFFFFFFFF;
                        else Rd = resTemp;
                    }
                }}, iv={{overflow}});
            0x1F: IntOpCcRes::sdivcc({{
                    int64_t val2 = Rs2_or_imm13.sdw<31:0>;
                    bool overflow = false, underflow = false;
                    if(val2 == 0) fault = new DivisionByZero;
                    else
                    {
                        Rd = (int64_t)((Y << 32) | Rs1.sdw<31:0>) / val2;
                        overflow = ((int64_t)Rd >= std::numeric_limits<int32_t>::max());
                        underflow = ((int64_t)Rd <= std::numeric_limits<int32_t>::min());
                        if(overflow) Rd = 0x7FFFFFFF;
                        else if(underflow) Rd = ULL(0xFFFFFFFF80000000);
                    }
                }}, iv={{overflow || underflow}});
            0x20: taddcc({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = Rs1 + op2;
                }}, iv={{
                    (op1 & mask(2)) || (op2 & mask(2)) ||
                    findOverflow(32, res, op1, op2)
                }});
            0x21: tsubcc({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = Rs1 - op2;
                }}, iv={{
                    (op1 & mask(2)) || (op2 & mask(2)) ||
                    findOverflow(32, res, op1, ~op2)
                }}, sub=True);
            0x22: taddcctv({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = op1 + op2;
                    bool overflow = (op1 & mask(2)) || (op2 & mask(2)) ||
                        findOverflow(32, res, op1, op2);
                    if(overflow) fault = new TagOverflow;
                }}, iv={{overflow}});
            0x23: tsubcctv({{
                    int64_t res, op1 = Rs1, op2 = Rs2_or_imm13;
                    Rd = res = op1 - op2;
                    bool overflow = (op1 & mask(2)) || (op2 & mask(2)) ||
                        findOverflow(32, res, op1, ~op2);
                    if(overflow) fault = new TagOverflow;
                }}, iv={{overflow}}, sub=True);
            0x24: mulscc({{
                    int32_t savedLSB = Rs1<0:>;

                    //Step 1
                    int64_t multiplicand = Rs2_or_imm13;
                    //Step 2
                    int32_t partialP = Rs1<31:1> |
                        ((Ccr<3:3> ^ Ccr<1:1>) << 31);
                    //Step 3
                    int32_t added = Y<0:> ? multiplicand : 0;
                    int64_t res, op1 = partialP, op2 = added;
                    Rd = res = partialP + added;
                    //Steps 4 & 5
                    Y = Y<31:1> | (savedLSB << 31);
                }});
        }
        format IntOp
        {
            0x25: decode X {
                0x0: sll({{Rd = Rs1 << (I ? SHCNT32 : Rs2<4:0>);}});
                0x1: sllx({{Rd = Rs1 << (I ? SHCNT64 : Rs2<5:0>);}});
            }
            0x26: decode X {
                0x0: srl({{Rd = Rs1.uw >> (I ? SHCNT32 : Rs2<4:0>);}});
                0x1: srlx({{Rd = Rs1.udw >> (I ? SHCNT64 : Rs2<5:0>);}});
            }
            0x27: decode X {
                0x0: sra({{Rd = Rs1.sw >> (I ? SHCNT32 : Rs2<4:0>);}});
                0x1: srax({{Rd = Rs1.sdw >> (I ? SHCNT64 : Rs2<5:0>);}});
            }