cntd
CNTD <Xd>{, <pattern>{, MUL #<imm>}}
Count Doublewords in Vector.
Pseudocode Operation
No pseudocode available.
Encoding
Binary Layout
00000100
31:24
1
23
1
22
10
21:20
imm4
19:16
11100
15:11
0
10
pattern
9:5
Rd
4:0
Related
More in SVE
Reference
View in Arm A64 ISA Reference ↗
Arm A64 ISA
Instruction Forms
| Encoding | Instruction | ISA | Bit pattern | ||
|---|---|---|---|---|---|
| 0x04E0E000 | CNTD <Xd>{, <pattern>{, MUL #<imm>}} | A64 | 00000100 | 1 | 1 | 10 | imm4 | 11100 | 0 | pattern | Rd |
Description
Determines the number of active elements implied by the named predicate constraint, multiplies that by an immediate in the range 1 to 16 inclusive, and then places the result in the scalar destination. The named predicate constraint limits the number of active elements in a single predicate to: Unspecified or out of range constraint encodings generate an empty predicate or zero element count rather than Undefined Instruction exception.
Operation
CheckSVEEnabled(); integer count = DecodePredCount(pat, esize); X[d, 64] = (count * imm)<63:0>;