SUBPT (unpredicated)

Subtract checked pointer vectors (unpredicated)

Subtract with pointer check all elements of the second source vector from corresponding elements of the first source vector and place the results in the corresponding elements of the destination vector. This instruction is unpredicated.

This instruction is illegal when executed in Streaming SVE mode, unless FEAT_SME_FA64 is implemented and enabled.

Encoding: SVE2

Variants: FEAT_SVE && FEAT_CPA (FEAT_SVE && FEAT_CPA)

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	0	1	1	1						0	0	0	0	1	1
								size			Zm								opc			Zn					Zd

SUBPT <Zd>.D, <Zn>.D, <Zm>.D

Decoding algorithm

if !IsFeatureImplemented(FEAT_SVE) || !IsFeatureImplemented(FEAT_CPA) then
    EndOfDecode(Decode_UNDEF);
constant integer n = UInt(Zn);
constant integer m = UInt(Zm);
constant integer d = UInt(Zd);

Operation

CheckNonStreamingSVEEnabled();
constant integer VL = CurrentVL;
constant integer elements = VL DIV 64;
constant bits(VL) operand1 = Z[n, VL];
constant bits(VL) operand2 = Z[m, VL];
bits(VL) result;

for e = 0 to elements-1
    constant bits(64) element1 = Elem[operand1, e, 64];
    constant bits(64) element2 = Elem[operand2, e, 64];
    constant bits(64) res = element1 - element2;
    Elem[result, e, 64] = PointerAddCheck(res, element1);

Z[d, VL] = result;

Explanations

<Zd>: Is the name of the destination scalable vector register, encoded in the "Zd" field.
<Zn>: Is the name of the first source scalable vector register, encoded in the "Zn" field.
<Zm>: Is the name of the second source scalable vector register, encoded in the "Zm" field.