URSHL (multiple vectors) -- A64

This instruction shifts the unsigned elements of the two or four first source vectors by the corresponding elements of the two or four second source vectors, and destructively places the rounded results in the corresponding elements of the two or four first source vectors. A positive shift amount performs a left shift, otherwise a right shift by the negated shift amount is performed.

Two registers
(FEAT_SME2)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << UInt(size); let dn : integer = UInt(Zdn::'0'); let m : integer = UInt(Zm::'0'); let nreg : integer{} = 2;

Four registers
(FEAT_SME2)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << UInt(size); let dn : integer = UInt(Zdn::'00'); let m : integer = UInt(Zm::'00'); let nreg : integer{} = 4;

Assembler Symbols

<Zdn1>	For the "Two registers" variant: is the name of the first scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 2.
	For the "Four registers" variant: is the name of the first scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 4.

<T>

Is the size specifier, encoded in size:

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

<Zdn2>

Is the name of the second scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 2 plus 1.

<Zm1>	For the "Two registers" variant: is the name of the first scalable vector register of the second source multi-vector group, encoded as "Zm" times 2.
	For the "Four registers" variant: is the name of the first scalable vector register of the second source multi-vector group, encoded as "Zm" times 4.

<Zm2>

Is the name of the second scalable vector register of the second source multi-vector group, encoded as "Zm" times 2 plus 1.

<Zdn4>

Is the name of the fourth scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 4 plus 3.

<Zm4>

Is the name of the fourth scalable vector register of the second source multi-vector group, encoded as "Zm" times 4 plus 3.

Operation

CheckStreamingSVEEnabled(); let VL : integer{} = CurrentVL(); let elements : integer = VL DIV esize; var results : array [[4]] of bits(VL); for r = 0 to nreg-1 do let operand1 : bits(VL) = Z{}(dn+r); let operand2 : bits(VL) = Z{}(m+r); for e = 0 to elements-1 do let element : integer = UInt(operand1[e*:esize]); var shift : integer = ShiftSat(SInt(operand2[e*:esize]), esize); var res : integer; if shift >= 0 then res = element << shift; else shift = -shift; res = (element + (1 << (shift - 1))) >> shift; end; results[[r]][e*:esize] = res[esize-1:0]; end; end; for r = 0 to nreg-1 do Z{VL}(dn+r) = results[[r]]; end;

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

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
1	1	0	0	0	0	0	1	size		1	Zm				0	1	0	1	1	0	0	1	0	0	0	1	Zdn				1
																								opc							U

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
1	1	0	0	0	0	0	1	size		1	Zm			0	0	1	0	1	1	1	0	1	0	0	0	1	Zdn			0	1
																								opc							U