Compare and Branch on Zero compares the value in a register with zero, and conditionally branches to a label at a PC-relative offset if the comparison is equal. It provides a hint that this is not a subroutine call or return. This instruction does not affect condition flags.
| 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 |
| sf | 0 | 1 | 1 | 0 | 1 | 0 | 0 | imm19 | Rt | ||||||||||||||||||||||
| op | |||||||||||||||||||||||||||||||
integer t = UInt(Rt); integer datasize = if sf == '1' then 64 else 32; boolean iszero = (op == '0'); bits(64) offset = SignExtend(imm19:'00', 64);
| <Wt> |
Is the 32-bit name of the general-purpose register to be tested, encoded in the "Rt" field. |
| <Xt> |
Is the 64-bit name of the general-purpose register to be tested, encoded in the "Rt" field. |
| <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. |
bits(datasize) operand1 = X[t]; boolean branch_conditional = TRUE; if IsZero(operand1) == iszero then BranchTo(PC[] + offset, BranchType_DIR, branch_conditional);
Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41
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