CB<cc> (immediate)
Compare register with immediate and branch
This instruction compares the value in a register with an immediate,
and conditionally branches to a label at a PC-relative offset if the
comparison 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
CBGE (immediate)
Never
CBHS (immediate)
Never
CBLE (immediate)
Never
CBLS (immediate)
Never
See
below for details of when each alias is preferred.
1
1
1
0
1
0
1
0
0
0
0
0
CBGT <Wt>, #<imm>, <label>
0
0
0
1
CBLT <Wt>, #<imm>, <label>
0
0
1
0
CBHI <Wt>, #<imm>, <label>
0
0
1
1
CBLO <Wt>, #<imm>, <label>
0
1
1
0
CBEQ <Wt>, #<imm>, <label>
0
1
1
1
CBNE <Wt>, #<imm>, <label>
1
0
0
0
CBGT <Xt>, #<imm>, <label>
1
0
0
1
CBLT <Xt>, #<imm>, <label>
1
0
1
0
CBHI <Xt>, #<imm>, <label>
1
0
1
1
CBLO <Xt>, #<imm>, <label>
1
1
1
0
CBEQ <Xt>, #<imm>, <label>
1
1
1
1
CBNE <Xt>, #<imm>, <label>
if !IsFeatureImplemented(FEAT_CMPBR) then EndOfDecode(Decode_UNDEF); end;
let datasize : integer{} = 32 << UInt(sf);
let t : integer = UInt(Rt);
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_LT; unsigned = FALSE;
when '010' => op = Cmp_GT; unsigned = TRUE;
when '011' => op = Cmp_LT; unsigned = TRUE;
when '110' => op = Cmp_EQ; unsigned = TRUE;
when '111' => op = Cmp_NE; unsigned = TRUE;
otherwise => EndOfDecode(Decode_UNDEF);
end;
let value2 : integer = UInt(imm6);
<Wt>
Is the 32-bit name of the general-purpose register to be tested, encoded in the "Rt" field.
<imm>
Is an unsigned immediate, in the range 0 to 63, encoded in the "imm6" 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.
Alias Conditions
let operand1 : bits(datasize) = X{}(t);
let branch_conditional : boolean = TRUE;
let value1 : integer = if unsigned then UInt(operand1) else SInt(operand1);
var cond : boolean;
case op of
when Cmp_EQ => cond = value1 == value2;
when Cmp_NE => cond = value1 != value2;
when Cmp_LT => 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