UABAL

Two-way unsigned absolute difference sum and accumulate long

This instruction computes the sum of the absolute difference between even-numbered unsigned elements and the absolute difference between the odd-numbered unsigned elements of each double-width container of the first and second vectors, and destructively adds the results to the overlapping double-width elements of the addend vector.

This instruction is unpredicated.

SVE2 class

(FEAT_SVE2p3 || FEAT_SME2p3)

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	1	0	0	0	1	0	0	size		0	Zm					1	1	0	1	1	1	Zn					Zda
																				U

Encoding

UABAL <Zda>.<T>, <Zn>.<Tb>, <Zm>.<Tb>

Decode

if !IsFeatureImplemented(FEAT_SVE2p3) && !IsFeatureImplemented(FEAT_SME2p3) then EndOfDecode(Decode_UNDEF); if size == '00' then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer da = UInt(Zda);

Assembler Symbols

<Zda>

Is the name of the third source and destination scalable vector register, encoded in the "Zda" field.

<T>

Is the size specifier, encoded in size:

size	<T>
00	RESERVED
01	H
10	S
11	D

<Zn>	Is the name of the first source scalable vector register, encoded in the "Zn" field.

<Tb>

Is the size specifier, encoded in size:

size	<Tb>
00	RESERVED
01	B
10	H
11	S

<Zm>	Is the name of the second source scalable vector register, encoded in the "Zm" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV esize; constant bits(VL) operand1 = Z[n, VL]; constant bits(VL) operand2 = Z[m, VL]; bits(VL) result = Z[da, VL]; for e = 0 to elements-1 constant integer elt1_a = UInt(Elem[operand1, 2*e + 0, esize DIV 2]); constant integer elt1_b = UInt(Elem[operand1, 2*e + 1, esize DIV 2]); constant integer elt2_a = UInt(Elem[operand2, 2*e + 0, esize DIV 2]); constant integer elt2_b = UInt(Elem[operand2, 2*e + 1, esize DIV 2]); constant integer sum = Abs(elt1_a - elt2_a) + Abs(elt1_b - elt2_b); Elem[result, e, esize] = Elem[result, e, esize] + sum<esize-1:0>; Z[da, VL] = result;

Operational information

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

This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is CONSTRAINED UNPREDICTABLE:

The MOVPRFX must be unpredicated.
The MOVPRFX must specify the same destination register as this instruction.
The destination register must not refer to architectural register state referenced by any other source operand register of this instruction.

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