TRN1, TRN2 (predicates)

Interleave even or odd elements from two predicates

Interleave alternating even or odd-numbered elements from the first and second source predicates and place in elements of the destination predicate. This instruction is unpredicated.

Encoding: Even

Variants: FEAT_SVE || FEAT_SME (FEAT_SVE || FEAT_SME)

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	0	0	0	1	0	1			1	0					0	1	0	1	0	0	0					0
								size				Pm							opc		H		Pn					Pd

TRN1 <Pd>.<T>, <Pn>.<T>, <Pm>.<T>

Decoding algorithm

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then
    EndOfDecode(Decode_UNDEF);
constant integer esize = 8 << UInt(size);
constant integer n = UInt(Pn);
constant integer m = UInt(Pm);
constant integer d = UInt(Pd);
constant integer part = 0;

Encoding: Odd

Variants: FEAT_SVE || FEAT_SME (FEAT_SVE || FEAT_SME)

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	0	0	0	1	0	1			1	0					0	1	0	1	0	1	0					0
								size				Pm							opc		H		Pn					Pd

TRN2 <Pd>.<T>, <Pn>.<T>, <Pm>.<T>

Decoding algorithm

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then
    EndOfDecode(Decode_UNDEF);
constant integer esize = 8 << UInt(size);
constant integer n = UInt(Pn);
constant integer m = UInt(Pm);
constant integer d = UInt(Pd);
constant integer part = 1;

Operation

CheckSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
constant integer pairs = VL DIV (esize * 2);
constant bits(PL) operand1 = P[n, PL];
constant bits(PL) operand2 = P[m, PL];
bits(PL) result;

for p = 0 to pairs-1
    Elem[result, 2*p+0, esize DIV 8] = Elem[operand1, 2*p+part, esize DIV 8];
    Elem[result, 2*p+1, esize DIV 8] = Elem[operand2, 2*p+part, esize DIV 8];

P[d, PL] = result;

Explanations

<Pd>: Is the name of the destination scalable predicate register, encoded in the "Pd" field.
<T>: <Pn>: Is the name of the first source scalable predicate register, encoded in the "Pn" field.
<Pm>: Is the name of the second source scalable predicate register, encoded in the "Pm" field.

Operational Notes

If PSTATE.DIT is 1:

• The execution time of this instruction is independent of:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.
• The response of this instruction to asynchronous exceptions does not vary based on:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.