CB<cc> (register) Compare registers and branch This instruction compares the values in two registers, and conditionally branches to a label at a PC-relative offset if the condition is true. This instruction provides a hint that this is not a subroutine call or return. This instruction does not affect the condition flags. This instruction is used by the aliases CBLE (register) Never CBLO (register) Never CBLS (register) Never CBLT (register) Never See below for details of when each alias is preferred. 1 1 1 0 1 0 0 0 0 0 0 0 0 CBGT <Wt>, <Wm>, <label> 0 0 0 1 CBGE <Wt>, <Wm>, <label> 0 0 1 0 CBHI <Wt>, <Wm>, <label> 0 0 1 1 CBHS <Wt>, <Wm>, <label> 0 1 1 0 CBEQ <Wt>, <Wm>, <label> 0 1 1 1 CBNE <Wt>, <Wm>, <label> 1 0 0 0 CBGT <Xt>, <Xm>, <label> 1 0 0 1 CBGE <Xt>, <Xm>, <label> 1 0 1 0 CBHI <Xt>, <Xm>, <label> 1 0 1 1 CBHS <Xt>, <Xm>, <label> 1 1 1 0 CBEQ <Xt>, <Xm>, <label> 1 1 1 1 CBNE <Xt>, <Xm>, <label> if !IsFeatureImplemented(FEAT_CMPBR) then EndOfDecode(Decode_UNDEF); end; let datasize : integer{} = 32 << UInt(sf); let t : integer = UInt(Rt); let m : integer = UInt(Rm); let offset : bits(64) = SignExtend{}(imm9::'00'); var op : CmpOp; var unsigned : boolean; case cc of when '000' => op = Cmp_GT; unsigned = FALSE; when '001' => op = Cmp_GE; unsigned = FALSE; when '010' => op = Cmp_GT; unsigned = TRUE; when '011' => op = Cmp_GE; unsigned = TRUE; when '110' => op = Cmp_EQ; unsigned = TRUE; when '111' => op = Cmp_NE; unsigned = TRUE; otherwise => EndOfDecode(Decode_UNDEF); end; <Wt> Is the 32-bit name of the general-purpose register to be tested, encoded in the "Rt" field. <Wm> Is the 32-bit name of the second general-purpose source register, encoded in the "Rm" field. <label> Is the program label to be conditionally branched to. Its offset from the address of this instruction, in the range -1024 to 1020, is encoded as "imm9" times 4. <Xt> Is the 64-bit name of the general-purpose register to be tested, encoded in the "Rt" field. <Xm> Is the 64-bit name of the second general-purpose source register, encoded in the "Rm" field. Alias Conditions let operand1 : bits(datasize) = X{}(t); let operand2 : bits(datasize) = X{}(m); let branch_conditional : boolean = TRUE; let value1 : integer = if unsigned then UInt(operand1) else SInt(operand1); let value2 : integer = if unsigned then UInt(operand2) else SInt(operand2); var cond : boolean; case op of when Cmp_EQ => cond = value1 == value2; when Cmp_NE => cond = value1 != value2; when Cmp_GE => cond = value1 >= value2; when Cmp_GT => cond = value1 > value2; end; if cond then BranchTo{64}(PC64() + offset, BranchType_DIR, branch_conditional); else BranchNotTaken(BranchType_DIR, branch_conditional); end; 2026-03-12 12:23:09 2025-09_rel_asl1