UQSUB (vectors, unpredicated)

Unsigned saturating subtract vectors (unpredicated)

Unsigned saturating subtract 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. Each result element is saturated to the N-bit element's unsigned integer range 0 to (2N)-1. This instruction is unpredicated.

Encoding: SVE

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	0			1						0	0	0	1	1	1
								size			Zm										U	Zn					Zd

UQSUB <Zd>.<T>, <Zn>.<T>, <Zm>.<T>

Decoding algorithm

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then
    EndOfDecode(Decode_UNDEF);
constant integer esize = 8 << UInt(size);
constant integer n = UInt(Zn);
constant integer m = UInt(Zm);
constant integer d = UInt(Zd);
constant boolean unsigned = TRUE;

Operation

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

for e = 0 to elements-1
    constant integer element1 = Int(Elem[operand1, e, esize], unsigned);
    constant integer element2 = Int(Elem[operand2, e, esize], unsigned);
    (Elem[result, e, esize], -) = SatQ(element1 - element2, esize, unsigned);

Z[d, VL] = result;

Explanations

<Zd>: Is the name of the destination scalable vector register, encoded in the "Zd" field.
<T>: <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.