LDFMINNM, LDFMINNMA, LDFMINNMAL, LDFMINNML

Atomic floating-point minimum number

This instruction atomically loads a 16-bit, 32-bit, or 64-bit value from memory, calculates the floating-point minimum number with the value held in a register, and stores the result back to memory. The value initially loaded from memory is returned in the destination register.

LDFMINNMA and LDFMINNMAL load from memory with acquire semantics.

LDFMINNML and LDFMINNMAL store to memory with release semantics.

LDFMINNM has neither acquire nor release semantics.

This instruction:

Disables alternative floating-point behaviors, as if FPCR.AH is 0.

Generates only the default NaN, as if FPCR.DN is 1.

Does not modify the cumulative FPSR exception bits (IDC, IXC, UFC, OFC, DZC, and IOC).

Disables trapped floating-point exceptions, as if the FPCR trap enable bits (IDE, IXE, UFE, OFE, DZE, and IOE) are all zero.

For more information about memory ordering semantics, see Load-Acquire, Store-Release.

For information about addressing modes, see Load/Store addressing modes.

Floating-point
(FEAT_LSFE)

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
size		1	1	1	1	0	0	A	R	1	Rs					0	1	1	1	0	0	Rn					Rt
					VR											o3	opc

Decode for all variants of this encoding

if !IsFeatureImplemented(FEAT_LSFE) then EndOfDecode(Decode_UNDEF); end; let t : integer = UInt(Rt); let n : integer = UInt(Rn); let s : integer = UInt(Rs); let datasize : integer{} = 8 << UInt(size); let acquire : boolean = A == '1'; let release : boolean = R == '1'; let tagchecked : boolean = n != 31;

Assembler Symbols

<Hs>	Is the 16-bit name of the SIMD&FP register holding the data value to be operated on with the contents of the memory location, encoded in the "Rs" field.

<Ht>	Is the 16-bit name of the SIMD&FP register to be loaded, encoded in the "Rt" field.

<Xn|SP>

Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.

<Ss>	Is the 32-bit name of the SIMD&FP register holding the data value to be operated on with the contents of the memory location, encoded in the "Rs" field.

<St>	Is the 32-bit name of the SIMD&FP register to be loaded, encoded in the "Rt" field.

<Ds>	Is the 64-bit name of the SIMD&FP register holding the data value to be operated on with the contents of the memory location, encoded in the "Rs" field.

<Dt>	Is the 64-bit name of the SIMD&FP register to be loaded, encoded in the "Rt" field.

Operation

AArch64_CheckFPEnabled(); var address : bits(64); var value : bits(datasize); var data : bits(datasize); let accdesc : AccessDescriptor = CreateAccDescFPAtomicOp(MemAtomicOp_FPMINNM, acquire, release, tagchecked); value = V{datasize}(s); if n == 31 then CheckSPAlignment(); address = SP{64}(); else address = X{64}(n); end; let comparevalue : bits(datasize) = ARBITRARY : bits(datasize); // Irrelevant when not executing CAS data = MemAtomic{datasize}(address, comparevalue, value, accdesc); V{datasize}(t) = data;

2026-03_rel 2026-03-26 20:48:11