xref: /gem5/src/arch/mips/isa/decoder.isa

////////////////////////////////////////////////////////////////////
//
// The actual MIPS32 ISA decoder 
// -----------------------------
// The following instructions are specified in the MIPS32 ISA
// Specification. Decoding closely follows the style specified 
// in the MIPS32 ISAthe specification document starting with Table
// A-2 (document available @ www.mips.com)
//
//@todo: Distinguish "unknown/future" use insts from "reserved"
// ones
decode OPCODE_HI default FailUnimpl::unknown() {
    
    // Derived From ... Table A-2 MIPS32 ISA Manual
    0x0: decode OPCODE_LO default FailUnimpl::reserved(){
	
	0x0: decode FUNCTION_HI {
	    0x0: decode FUNCTION_LO {
	      0x1: decode MOVCI {
		format Move {
		  0: movf({{ if( FPConditionCode(CC) == 0) Rd = Rs}});
		  1: movt({{ if( FPConditionCode(CC) == 1) Rd = Rs}});
		}  
	      }

	      format BasicOp {

		//Table A-3 Note: "1. Specific encodings of the rt, rd, and sa fields 
		//are used to distinguish among the SLL, NOP, SSNOP and EHB functions."

		0x0: sll({{ Rd = Rt.uw << SA; }});
		
		0x2: decode SRL {
		   0: srl({{ Rd = Rt.uw >> SA; }});

		   //Hardcoded assuming 32-bit ISA, probably need parameter here
		   1: rotr({{ Rd = (Rt.uw << (32 - SA)) | (Rt.uw >> SA);}});
		 }	
	
		 0x3: sra({{ Rd = Rt.sw >> SA; }});
		
		 0x4: sllv({{ Rd = Rt.uw << Rs<4:0>; }});

		 0x6: decode SRLV {
		   0: srlv({{ Rd = Rt.uw >> Rs<4:0>; }});

		   //Hardcoded assuming 32-bit ISA, probably need parameter here
		   1: rotrv({{ Rd = (Rt.uw << (32 - Rs<4:0>)) | (Rt.uw >> Rs<4:0>);}});
		 }

		 0x7: srav({{ Rd = Rt.sw >> Rs<4:0>; }});
	      }
	    }

	    0x1: decode FUNCTION_LO {
	     
	      //Table A-3 Note: "Specific encodings of the hint field are used 
	      //to distinguish JR from JR.HB and JALR from JALR.HB"
	      format Jump {
		0x0: jr(IsReturn);
		0x1: jalr(IsCall,IsReturn);
	      }

	      format Move {
		0x2: movz({{ if (Rt == 0) Rd = Rs; }});
		0x3: movn({{ if (Rt != 0) Rd = Rs; }});
	      }

	      format Trap {
	      	0x4: Syscall::syscall({{ xc->syscall()}},IsNonSpeculative);
	      	0x5: Break::break({{ }});
	      	0x7: Synchronize::sync({{ }});
	      }
	    }

	    0x2: decode FUNCTION_LO {
	      format IntOp {
		0x0: mfhi({{ }});
		0x1: mthi({{ }});
		0x2: mflo({{ }});
		0x3: mtlo({{ }});
	      }
	    };

	    0x3: decode FUNCTION_LO {
	      format IntOp {
		0x0: mult({{ Rd.sw = Rs.sw * Rt.sw; }});
		0x1: multu({{ Rd.sw = Rs.uw * Rt.uw;}});
		0x2: div({{ Rd.sw = Rs.sw / Rt.sw;}});
		0x3: divu({{ Rd.sw = Rs.sw / Rt.uw;}});
	      }
	    };

	    0x4: decode FUNCTION_LO {
	      format IntOp {
		0x0: add({{  Rd.sw = Rs.sw + Rt.sw;}});
		0x1: addu({{ Rd.uw = Rs.uw + Rt.uw;}});
		0x2: sub({{ Rd.sw = Rs.sw - Rt.sw;}});
		0x3: subu({{ Rd.uw = Rs.uw - Rt.uw;}});	      
		0x4: and({{ Rd.sw = Rs.uw & Rt.uw;}});
		0x5: or({{ Rd.sw = Rs.uw | Rt.uw;}});
		0x6: xor({{ Rd.sw = Rs.uw ^ Rt.uw;}});
		0x7: nor({{ Rd.sw = ~(Rs.uw | Rt.uw);}});
	      }
	    }

	    0x5: decode FUNCTION_LO {
	      format IntOp{
		0x2: slt({{  Rd.sw = ( Rs.sw < Rt.sw ) ? 1 : 0}});
		0x3: sltu({{ Rd.uw = ( Rs.uw < Rt.uw ) ? 1 : 0}});
	      }
	    };

	    0x6: decode FUNCTION_LO {
	      format Trap {
		 0x0: tge({{ }});
		 0x1: tgeu({{ }});
		 0x2: tlt({{ }});
		 0x3: tltu({{ }});
		 0x4: teq({{ }});
		 0x6: tne({{ }});
	      }
	    }
	}

	0x1: decode REGIMM_HI {
	    0x0: decode REGIMM_LO {
	      format Branch {
		0x0: bltz({{ }});
		0x1: bgez({{ }});

		//MIPS obsolete instructions
		0x2: bltzl({{ }});
		0x3: bgezl({{ }});
	      }
	    }

	    0x1: decode REGIMM_LO {
	      format Trap {
		 0x0: tgei({{ }});
		 0x1: tgeiu({{ }});
		 0x2: tlti({{ }});
		 0x3: tltiu({{ }});
		 0x4: teqi({{ }});
		 0x6: tnei({{ }});
	      }
	    }

	    0x2: decode REGIMM_LO {
	      format Branch {
		0x0: bltzal({{ }});
		0x1: bgezal({{ }});

		//MIPS obsolete instructions
		0x2: bltzall({{ }});
		0x3: bgezall({{ }});
	      }
	    }

	    0x3: decode REGIMM_LO {
	      format Trap {
	      	0x7: synci({{ }});
	      }
	    }      
	}

	format Jump {
	    0x2: j();
	    0x3: jal(IsCall);
	}

	format Branch {
	    0x4: beq({{ }});
	    0x5: bne({{ }});
	    0x6: blez({{ }});
	    0x7: bgtz({{ }});
	}
    };

    0x1: decode OPCODE_LO default FailUnimpl::reserved(){
	format IntOp {
	    0x0: addi({{ Rt.sw = Rs.sw + INTIMM; }});
	    0x1: addiu({{ Rt.uw = Rs.uw + INTIMM;}});
	    0x2: slti({{ Rt.sw = ( Rs.sw < INTIMM ) ? 1 : 0 }});
	    0x3: sltiu({{ Rt.uw = ( Rs.uw < INTIMM ) ? 1 : 0 }});
	    0x4: andi({{ Rt.sw = Rs.sw & INTIMM;}});
	    0x5: ori({{ Rt.sw = Rs.sw | INTIMM;}});
	    0x6: xori({{ Rt.sw = Rs.sw ^ INTIMM;}});
	};

	format Memory {
	    0x7: lui({{ }});
	};
    };

    0x2: decode OPCODE_LO default FailUnimpl::reserved(){

      //Table A-11 MIPS32 COP0 Encoding of rs Field
      0x0: decode RS_MSB {
	0x0: decode RS {
	  0x0: mfc0({{ }});
	  0xC: mtc0({{ }});
	  0xA: rdpgpr({{ }});

  	  0xB: decode SC {
	    format BasicOp {
		0x0: di({{ }});
		0x1: ei({{ }}); 	      
	    }
	  }

  	  0xE: wrpgpr({{ }});
	}

	//Table A-12 MIPS32 COP0 Encoding of Function Field When rs=CO
	0x1: decode FUNCTION {
	  format Trap {
	        0x01: tlbr({{ }});
	        0x02: tlbwi({{ }});
	        0x06: tlbwr({{ }});
	        0x08: tlbp({{ }});
	  }

	  format BasicOp {
	        0x18: eret({{ }});
	        0x1F: deret({{ }});
	        0x20: wait({{ }});
          }
	}
      }

      //Table A-13 MIPS32 COP1 Encoding of rs Field
      0x1: decode RS_MSB {

	0x0: decode RS_HI {
	  0x0: decode RS_LO {
	    0x0: mfc1({{ }});
	    0x2: cfc1({{ }});
	    0x3: mfhc1({{ }});
	    0x4: mtc1({{ }});
	    0x6: ctc1({{ }});
	    0x7: mftc1({{ }});
	  }

	  0x1: decode ND {
	    0x0: decode TF {
	      format Branch {
	      	0x0: bc1f({{ }});
	      	0x1: bc1t({{ }});
	      }
	    }

	    0x1: decode TF {
	      format Branch {
		0x0: bc1fl({{ }});
	      	0x1: bc1tl({{ }});
	      }
	    }
	  }
	}

	0x1: decode RS_HI {
	  0x2: decode RS_LO {

	    //Table A-14 MIPS32 COP1 Encoding of Function Field When rs=S
	    //(( single-word ))
	    0x0: decode RS_HI {
	      0x0: decode RS_LO {
		0x0: add_fmt({{ }});
		0x1: sub_fmt({{ }});
		0x2: mul_fmt({{ }});
		0x3: div_fmt({{ }});
		0x4: sqrt_fmt({{ }});
		0x5: abs_fmt({{ }});
		0x6: mov_fmt({{ }});
		0x7: neg_fmt({{ }});
	      }

	      0x1: decode RS_LO {
		//only legal for 64 bit
		format mode64 {
		  0x0: round_l({{ }});
		  0x1: trunc_l({{ }});
		  0x2: ceil_l({{ }});
		  0x3: floor_l({{ }});
		}

		0x4: round_w({{ }});
		0x5: trunc_w({{ }});
		0x6: ceil_w({{ }});
		0x7: floor_w({{ }});
	      }

	      0x2: decode RS_LO {
		0x1: decode MOVCF {
		  0x0: movf_fmt({{ }});
		  0x1: movt_fmt({{ }});
		}

		format Move {
		  0x2: movz({{ if (Rt == 0) Rd = Rs; }});
         	  0x3: movn({{ if (Rt != 0) Rd = Rs; }});
	      	}

		format mode64 {
		  0x2: recip({{ }});
		  0x3: rsqrt{{ }});
		}
	      }

	      0x4: decode RS_LO {
		0x1: cvt_d({{ }});
		0x4: cvt_w({{ }});

		//only legal for 64 bit
		format mode64 {
		  0x5: cvt_l({{ }});
		  0x6: cvt_ps({{ }});
		}
	      }
	    }

	    //Table A-15 MIPS32 COP1 Encoding of Function Field When rs=D
	    0x1: decode RS_HI {
	      0x0: decode RS_LO {
		0x0: add_fmt({{ }});
		0x1: sub_fmt({{ }});
		0x2: mul_fmt({{ }});
		0x3: div_fmt({{ }});
		0x4: sqrt_fmt({{ }});
		0x5: abs_fmt({{ }});
		0x6: mov_fmt({{ }});
		0x7: neg_fmt({{ }});
	      }

	      0x1: decode RS_LO {
		//only legal for 64 bit
		format mode64 {
		  0x0: round_l({{ }});
		  0x1: trunc_l({{ }});
		  0x2: ceil_l({{ }});
		  0x3: floor_l({{ }});
		}

		0x4: round_w({{ }});
		0x5: trunc_w({{ }});
		0x6: ceil_w({{ }});
		0x7: floor_w({{ }});
	      }

	      0x2: decode RS_LO {
		0x1: decode MOVCF {
		  0x0: movf_fmt({{ }});
		  0x1: movt_fmt({{ }});
		}

		format Move {
		  0x2: movz({{ if (Rt == 0) Rd = Rs; }});
         	  0x3: movn({{ if (Rt != 0) Rd = Rs; }});
	      	}

		format mode64 {
		  0x5: recip({{ }});
		  0x6: rsqrt{{ }});
		}
	      }

	      0x4: decode RS_LO {
		0x0: cvt_s({{ }});
		0x4: cvt_w({{ }});

		//only legal for 64 bit
		format mode64 {
		  0x5: cvt_l({{ }});
		}
	      }
	    }

	    //Table A-16 MIPS32 COP1 Encoding of Function Field When rs=W
	    0x4: decode FUNCTION {
	      0x10: cvt_s({{ }});
	      0x10: cvt_d({{ }});
	    }

	    //Table A-16 MIPS32 COP1 Encoding of Function Field When rs=L1
	    //Note: "1. Format type L is legal only if 64-bit floating point operations 
	    //are enabled."
	    0x5: decode FUNCTION_HI {
	      0x10: cvt_s({{ }});
	      0x11: cvt_d({{ }});
	    }

	    //Table A-17 MIPS64 COP1 Encoding of Function Field When rs=PS1
	    //Note: "1. Format type PS is legal only if 64-bit floating point operations 
	    //are enabled. "
	    0x6: decode RS_HI {
	      0x0: decode RS_LO {
		0x0: add_fmt({{ }});
		0x1: sub_fmt({{ }});
		0x2: mul_fmt({{ }});
		0x5: abs_fmt({{ }});
		0x6: mov_fmt({{ }});
		0x7: neg_fmt({{ }});
	      }

	      0x2: decode RS_LO {
		0x1: decode MOVCF {
		  0x0: movf_fmt({{ }});
		  0x1: movt_fmt({{ }});
		}

	      }

	      0x4: decode RS_LO {
		0x0: cvt_s_pu({{ }});
	      }

	      0x5: decode RS_LO {
		0x0: cvt_s_pl({{ }});
		0x4: pll_s_pl({{ }});
		0x5: plu_s_pl({{ }});
		0x6: pul_s_pl({{ }});
		0x7: puu_s_pl({{ }});
	      }
	    }
      }

      //Table A-19 MIPS32 COP2 Encoding of rs Field 
      0x2: decode RS_MSB {
	0x0: decode RS_HI {
	  0x0: decode RS_LO {
	    0x0: mfc2({{ }});
	    0x2: cfc2({{ }});
	    0x3: mfhc2({{ }});
	    0x4: mtc2({{ }});
	    0x6: ctc2({{ }});
	    0x7: mftc2({{ }});
	  }

	  0x1: decode ND {
	    0x0: decode TF {
	      format Branch { 
	        0x0: bc2f({{ }});
	        0x1: bc2t({{ }});
	      }
	    }

	    0x1: decode TF {
	      format Branch {
	      	0x0: bc2fl({{ }});
	      	0x1: bc2tl({{ }});
	      }
	    }
	  }
	}
      }

      //Table A-20 MIPS64 COP1X Encoding of Function Field 1
      //Note: "COP1X instructions are legal only if 64-bit floating point 
      //operations are enabled."
      0x3: decode FUNCTION_HI {
	0x0: decode FUNCTION_LO {
	  0x0: lwxc1({{ }});
	  0x1: ldxc1({{ }});
	  0x5: luxc1({{ }});
	}

	0x1: decode FUNCTION_LO {
	  0x0: swxc1({{ }});
	  0x1: sdxc1({{ }});
	  0x5: suxc1({{ }});
	  0x7: prefx({{ }});
	}

	0x3: alnv_ps({{ }});

	0x4: decode FUNCTION_LO {
	  0x0: madd_s({{ }});
	  0x1: madd_d({{ }});
	  0x6: madd_ps({{ }});
	}

	0x5: decode FUNCTION_LO {
	  0x0: msub_s({{ }});
	  0x1: msub_d({{ }});
	  0x6: msub_ps({{ }});	
	}

	0x6: decode FUNCTION_LO {
	  0x0: nmadd_s({{ }});
	  0x1: nmadd_d({{ }});
	  0x6: nmadd_ps({{ }});	
	}

	0x7: decode FUNCTION_LO {
	  0x0: nmsub_s({{ }});
	  0x1: nmsub_d({{ }});
	  0x6: nmsub_ps({{ }});
	}
      } 

      //MIPS obsolete instructions 
      0x4: beql({{ }});
      0x5: bnel({{ }});
      0x6: blezl({{ }});
      0x7: bgtzl({{ }});
    };

    0x3: decode OPCODE_LO default FailUnimpl::reserved() {

	//Table A-5 MIPS32 SPECIAL2 Encoding of Function Field
	0x4: decode FUNCTION_HI {

	    0x0: decode FUNCTION_LO {
	      0x0: madd({{ }});
	      0x1: maddu({{ }});
	      0x2: mult({{ }});
	      0x4: msub({{ }});
	      0x5: msubu({{ }});
	    }

	    0x4: decode FUNCTION_LO {
	      0x0: clz({{ }});
	      0x1: clo({{ }});
	    }

	    0x7: decode FUNCTION_LO {
	      0x7: sdbbp({{ }});
	    }	      
	}

	//Table A-6 MIPS32 SPECIAL3 Encoding of Function Field for Release 2 of the Architecture
	0x7: decode FUNCTION_HI {
	  
	  0x0: decode FUNCTION_LO {
	    0x1: ext({{ }});
	    0x4: ins({{ }});
	  }

	  //Table A-10 MIPS32 BSHFL Encoding of sa Field
	  0x4: decode SA {
	    0x02: wsbh({{ }});
	    0x10: seb({{ }});
	    0x18: seh({{ }});
	  }

	  0x6: decode FUNCTION_LO {
	    0x7: rdhwr({{ }});
	  }
	}
    };

    0x4: decode OPCODE_LO default FailUnimpl::reserved() {
	format Memory {
	    0x0: lb({{ }});
	    0x1: lh({{ }});
	    0x2: lwl({{ }});
	    0x3: lw({{ }});
	    0x4: lbu({{ }});
	    0x5: lhu({{ }});
	    0x6: lhu({{ }});
	};

	0x7: FailUnimpl::reserved({{ }});
    };

    0x5: decode OPCODE_LO default FailUnimpl::reserved() {
	format Memory {
	    0x0: sb({{ }});
	    0x1: sh({{ }});
	    0x2: swl({{ }});
	    0x3: sw({{ }});
	    0x6: swr({{ }});
	};

	format FailUnimpl {
	    0x4: reserved({{ }});
	    0x5: reserved({{ }});
	    0x7: cache({{ }});
	};

    };

    0x6: decode OPCODE_LO default FailUnimpl::reserved() {
	format Memory {
	    0x0: ll({{ }});
	    0x1: lwc1({{ }});
	    0x5: ldc1({{ }});
	};
    };

    0x7: decode OPCODE_LO default FailUnimpl::reserved() {
	format Memory {
	    0x0: sc({{ }});
	    0x1: swc1({{ }});
	    0x5: sdc1({{ }});
	};

    }
}