Atomic unsigned maximum on byte in memory, without return, atomically loads an 8-bit byte from memory, compares it against the value held in a register, and stores the larger value back to memory, treating the values as unsigned numbers.
For information about addressing modes, see Load/Store addressing modes.
This is an alias of LDUMAXB, LDUMAXAB, LDUMAXALB, LDUMAXLB. This means:
| 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 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | R | 1 | Rs | 0 | 1 | 1 | 0 | 0 | 0 | Rn | 1 | 1 | 1 | 1 | 1 | ||||||||
| size | VR | A | o3 | opc | Rt | ||||||||||||||||||||||||||
| <Ws> |
Is the 32-bit name of the general-purpose register holding the data value to be operated on with the contents of the memory location, encoded in the "Rs" field. |
| <Xn|SP> |
Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field. |
The description of LDUMAXB, LDUMAXAB, LDUMAXALB, LDUMAXLB gives the operational pseudocode for this instruction.
If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.
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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