Test bit and Branch if Nonzero compares the value of a bit in a general-purpose register with zero, and conditionally branches to a label at a PC-relative offset if the comparison is not 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 |
| b5 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | b40 | imm14 | Rt | |||||||||||||||||||||
| op | |||||||||||||||||||||||||||||||
integer t = UInt(Rt); constant integer datasize = 32 << UInt(b5); integer bit_pos = UInt(b5:b40); bit iszero = op; bits(64) offset = SignExtend(imm14:'00', 64);
| <R> |
Is a width specifier,
encoded in
|
| <t> |
Is the number [0-30] of the general-purpose register to be tested or the name ZR (31), encoded in the "Rt" field. |
| <imm> |
Is the bit number to be tested, in the range 0 to 63, encoded in "b5:b40". |
| <label> |
Is the program label to be conditionally branched to. Its offset from the address of this instruction, in the range +/-32KB, is encoded as "imm14" times 4. |
bits(datasize) operand = X[t, datasize]; boolean branch_conditional = TRUE; if operand<bit_pos> == iszero then BranchTo(PC64 + offset, BranchType_DIR, branch_conditional); else BranchNotTaken(BranchType_DIR, branch_conditional);
Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45
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