SABA

Signed absolute difference and accumulate

This instruction subtracts the elements of the vector of the second source SIMD&FP register from the corresponding elements of the first source SIMD&FP register, and accumulates the absolute values of the results into the elements of the vector of the destination SIMD&FP register.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.

Three registers of the same type
(FEAT_AdvSIMD)

313029282726252423222120191817161514131211109876543210
0Q001110size1Rm011111RnRd
Uac

Encoding

SABA <Vd>.<T>, <Vn>.<T>, <Vm>.<T>

Decode for this encoding

if !IsFeatureImplemented(FEAT_AdvSIMD) then EndOfDecode(Decode_UNDEF); end; if size == '11' then EndOfDecode(Decode_UNDEF); end; let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm); let esize : integer{} = 8 << UInt(size); let datasize : integer{} = 64 << UInt(Q); let elements : integer = datasize DIV esize;

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T>

Is an arrangement specifier, encoded in (size :: Q):

size Q <T>
00 0 8B
00 1 16B
01 0 4H
01 1 8H
10 0 2S
10 1 4S
11 x RESERVED
<Vn>

Is the name of the first SIMD&FP source register, encoded in the "Rn" field.

<Vm>

Is the name of the second SIMD&FP source register, encoded in the "Rm" field.

Operation

AArch64_CheckFPAdvSIMDEnabled(); let operand1 : bits(datasize) = V{}(n); let operand2 : bits(datasize) = V{}(m); var result : bits(datasize) = V{datasize}(d); var element1 : integer; var element2 : integer; var absdiff : bits(esize); for e = 0 to elements-1 do element1 = SInt(operand1[e*:esize]); element2 = SInt(operand2[e*:esize]); absdiff = Abs(element1 - element2)[esize-1:0]; result[e*:esize] = result[e*:esize] + absdiff; end; V{datasize}(d) = result;

Operational information

This instruction is a data-independent-time instruction as described in About PSTATE.DIT.


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

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