Signed saturating decrement scalar by count of true predicate elements
.
Counts the number of true elements in the source predicate and then uses the result to decrement the scalar destination. The result is saturated to the source general-purpose register's signed integer range. A 32-bit saturated result is then sign-extended to 64 bits.
It has encodings from 2 classes: 32-bit and 64-bit
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 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | size | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | Pm | Rdn | ||||||||
D | U | sf |
if !HaveSVE() then UNDEFINED; integer esize = 8 << UInt(size); integer m = UInt(Pm); integer dn = UInt(Rdn); boolean unsigned = FALSE; integer ssize = 32;
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 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | size | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | Pm | Rdn | ||||||||
D | U | sf |
if !HaveSVE() then UNDEFINED; integer esize = 8 << UInt(size); integer m = UInt(Pm); integer dn = UInt(Rdn); boolean unsigned = FALSE; integer ssize = 64;
<Xdn> |
Is the 64-bit name of the source and destination general-purpose register, encoded in the "Rdn" field. |
<Pm> |
Is the name of the source scalable predicate register, encoded in the "Pm" field. |
<T> |
Is the size specifier,
encoded in
|
<Wdn> |
Is the 32-bit name of the source and destination general-purpose register, encoded in the "Rdn" field. |
CheckSVEEnabled(); integer elements = VL DIV esize; bits(ssize) operand1 = X[dn]; bits(PL) operand2 = P[m]; bits(ssize) result; integer count = 0; for e = 0 to elements-1 if ElemP[operand2, e, esize] == '1' then count = count + 1; integer element = Int(operand1, unsigned); (result, -) = SatQ(element - count, ssize, unsigned); X[dn] = Extend(result, 64, unsigned);
Internal version only: isa v32.12, AdvSIMD v29.04, pseudocode v2020-09_xml, sve v2020-09_rc3 ; Build timestamp: 2020-11-18T17:23
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