REV (predicate)

Reverse all elements in a predicate

This instruction reads all elements in the source predicate, reverses the order of all the elements, and places the result in the destination predicate. This instruction is unpredicated.

SVE class

(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	size		1	1	0	1	0	0	0	1	0	0	0	0	0	Pn				0	Pd

Encoding

REV <Pd>.<T>, <Pn>.<T>

Decode

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

Assembler Symbols

<Pd>	Is the name of the destination scalable predicate register, encoded in the "Pd" field.

<T>

Is the size specifier, encoded in size:

size	<T>
00	B
01	H
10	S
11	D

<Pn>	Is the name of the source scalable predicate register, encoded in the "Pn" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant bits(PL) operand = P[n, PL]; constant bits(PL) result = Reverse(operand, esize DIV 8); P[d, PL] = result;