Test bit and Branch if Zero compares the value of a test bit 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 |
| b5 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | b40 | imm14 | Rt | |||||||||||||||||||||
| op | |||||||||||||||||||||||||||||||
integer t = UInt(Rt); integer datasize = if b5 == '1' then 64 else 32; integer bit_pos = UInt(b5:b40); bit bit_val = op; bits(64) offset = SignExtend(imm14:'00', 64);
| <R> |
Is a width specifier,
encoded in
b5:
|
| <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]; if operand<bit_pos> == bit_val then BranchToOffset(offset, BranchType_DIR);
Internal version only: isa v32.13, AdvSIMD v29.04, pseudocode morello-2022-01_rc2, capabilities morello-2022-01_rc2 ; Build timestamp: 2022-01-11T11:23
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