BC.cond

Branch consistent conditionally

This instruction branches conditionally to a label at a PC-relative offset, with a hint that this branch will behave very consistently and is very unlikely to change direction.

Encoding: 19-bit signed PC-relative branch offset

Variants: FEAT_HBC (ARMv8.8)

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	1	0	1	0	1	0	0																				1
								imm19																			o0	cond

BC.<cond> <label>

Decoding algorithm

if !IsFeatureImplemented(FEAT_HBC) then EndOfDecode(Decode_UNDEF);
constant bits(64) offset = SignExtend(imm19:'00', 64);
constant bits(4) condition = cond;

Operation

constant boolean branch_conditional = TRUE;
if ConditionHolds(condition) then
    BranchTo(PC64 + offset, BranchType_DIR, branch_conditional);
else
    BranchNotTaken(BranchType_DIR, branch_conditional);

Explanations

<cond>: <label>: Is the program label to be conditionally branched to. Its offset from the address of this instruction, in the range +/-1MB, is encoded as "imm19" times 4.