CMN (immediate)
Compare Negative (immediate) adds a register value and an optionally-shifted immediate value. It updates the condition flags based on the result, and discards the result.
This is an alias of ADDS (immediate). This means:
- The encodings in this description are named to match the encodings of ADDS (immediate).
- The description of ADDS (immediate) gives the operational pseudocode for this instruction.
| 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 | 0 | 0 | 1 | 0 | sh | imm12 | Rn | 1 | 1 | 1 | 1 | 1 | |||||||||||||||
| op | S | Rd | |||||||||||||||||||||||||||||
32-bit (sf == 0)
CMN <Wn|WSP>, #<imm>{, <shift>}
is equivalent to
ADDS WZR, <Wn|WSP>, #<imm> {, <shift>}
and is always the preferred disassembly.
64-bit (sf == 1)
CMN <Xn|SP>, #<imm>{, <shift>}
is equivalent to
ADDS XZR, <Xn|SP>, #<imm> {, <shift>}
and is always the preferred disassembly.
Assembler Symbols
| <Wn|WSP> |
Is the 32-bit name of the source general-purpose register or stack pointer, encoded in the "Rn" field. |
| <Xn|SP> |
Is the 64-bit name of the source general-purpose register or stack pointer, encoded in the "Rn" field. |
| <imm> |
Is an unsigned immediate, in the range 0 to 4095, encoded in the "imm12" field. |
| <shift> |
Is the optional left shift to apply to the immediate, defaulting to LSL #0 and
encoded in
sh:
|
Operation
The description of ADDS (immediate) gives the operational pseudocode for this instruction.
Operational information
If PSTATE.DIT is 1:
- The execution time of this instruction is independent of:
- The values of the data supplied in any of its registers.
- The values of the NZCV flags.
- The response of this instruction to asynchronous exceptions does not vary based on:
- The values of the data supplied in any of its registers.
- The values of the NZCV flags.