SUDOT (by element)

Dot product index form with signed and unsigned integers. This instruction performs the dot product of the four signed 8-bit integer values in each 32-bit element of the first source register with the four unsigned 8-bit integer values in an indexed 32-bit element of the second source register, accumulating the result into the corresponding 32-bit element of the destination vector.

From Armv8.2 to Armv8.5, this is an OPTIONAL instruction. From Armv8.6 it is mandatory for implementations that include Advanced SIMD to support it. ID_AA64ISAR1_EL1.I8MM indicates whether this instruction is supported.

Vector
(FEAT_I8MM)

313029282726252423222120191817161514131211109876543210
0Q00111100LMRm1111H0RnRd
UUSopcode

SUDOT <Vd>.<Ta>, <Vn>.<Tb>, <Vm>.4B[<index>]

if !IsFeatureImplemented(FEAT_I8MM) then UNDEFINED; boolean op1_unsigned = (US == '1'); boolean op2_unsigned = (US == '0'); integer n = UInt(Rn); integer m = UInt(M:Rm); integer d = UInt(Rd); integer i = UInt(H:L); constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV 32;

Assembler Symbols

<Vd>

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

<Ta>

Is an arrangement specifier, encoded in Q:

Q <Ta>
0 2S
1 4S
<Vn>

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

<Tb>

Is an arrangement specifier, encoded in Q:

Q <Tb>
0 8B
1 16B
<Vm>

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

<index>

Is the immediate index of a 32-bit group of four 8-bit values, in the range 0 to 3, encoded in the "H:L" fields.

Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand1 = V[n, datasize]; bits(128) operand2 = V[m, 128]; bits(datasize) operand3 = V[d, datasize]; bits(datasize) result; for e = 0 to elements-1 bits(32) res = Elem[operand3, e, 32]; for b = 0 to 3 integer element1 = Int(Elem[operand1, 4*e+b, 8], op1_unsigned); integer element2 = Int(Elem[operand2, 4*i+b, 8], op2_unsigned); res = res + element1 * element2; Elem[result, e, 32] = res; V[d, datasize] = result;


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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