SQDMLSL, SQDMLSL2 (vector)
Signed saturating Doubling Multiply-Subtract Long. This instruction multiplies corresponding signed integer values in the lower or upper half of the vectors of the two source SIMD&FP registers, doubles the results, and subtracts the final results from the vector elements of the destination SIMD&FP register. The destination vector elements are twice as long as the elements that are multiplied.
If overflow occurs with any of the results, those results are saturated. If saturation occurs, the cumulative saturation bit FPSR.QC is set.
The SQDMLSL instruction extracts each source vector from the lower half of each source register, while the SQDMLSL2 instruction extracts each source vector from the upper half of each source 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.
It has encodings from 2 classes:
Scalar
and
Vector
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 | 1 | 1 | 1 | 1 | 0 | size | 1 | Rm | 1 | 0 | 1 | 1 | 0 | 0 | Rn | Rd |
| | | | | | | o1 | | | | |
integer d = UInt(Rd);
integer n = UInt(Rn);
integer m = UInt(Rm);
if size == '00' || size == '11' then ReservedValue();
integer esize = 8 << UInt(size);
integer datasize = esize;
integer elements = 1;
integer part = 0;
boolean sub_op = (o1 == '1');
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 | Q | 0 | 0 | 1 | 1 | 1 | 0 | size | 1 | Rm | 1 | 0 | 1 | 1 | 0 | 0 | Rn | Rd |
| | | | | | | | o1 | | | | |
integer d = UInt(Rd);
integer n = UInt(Rn);
integer m = UInt(Rm);
if size == '00' || size == '11' then ReservedValue();
integer esize = 8 << UInt(size);
integer datasize = 64;
integer part = UInt(Q);
integer elements = datasize DIV esize;
boolean sub_op = (o1 == '1');
Assembler Symbols
Operation
CheckFPAdvSIMDEnabled64();
bits(datasize) operand1 = Vpart[n, part];
bits(datasize) operand2 = Vpart[m, part];
bits(2*datasize) operand3 = V[d];
bits(2*datasize) result;
integer element1;
integer element2;
bits(2*esize) product;
integer accum;
boolean sat1;
boolean sat2;
for e = 0 to elements-1
element1 = SInt(Elem[operand1, e, esize]);
element2 = SInt(Elem[operand2, e, esize]);
(product, sat1) = SignedSatQ(2 * element1 * element2, 2 * esize);
(2 * element1 * element2, 2*esize);
if sub_op then
accum = SInt(Elem[operand3, e, 2*esize]) - SInt(product);
else
accum = SInt(Elem[operand3, e, 2*esize]) + SInt(product);
(Elem[result, e, 2*esize], sat2) = SignedSatQ(accum, 2 * esize);
(accum, 2*esize);
if sat1 || sat2 then FPSR.QC = '1';
V[d] = result;
Internal version only: isa v25.07, AdvSIMD v23.0, pseudocode v31.3
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