UQADD8
Unsigned Saturating Add 8
Unsigned Saturating Add 8 performs four unsigned 8-bit integer additions, saturates the results to the 8-bit unsigned integer range 0 <= x <= 28 - 1, and writes the results to the destination register.
For more information about the constrained unpredictable behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors.
It has encodings from the following instruction sets:
A32 (
A1
)
and
T32 (
T1
)
.
!= 1111
0
1
1
0
0
1
1
0
(1)
(1)
(1)
(1)
1
0
0
1
UQADD8{<c>}{<q>} {<Rd>,} <Rn>, <Rm>
d = UInt(Rd); n = UInt(Rn); m = UInt(Rm);
if d == 15 || n == 15 || m == 15 then UNPREDICTABLE;
1
1
1
1
1
0
1
0
1
0
0
0
1
1
1
1
0
1
0
1
UQADD8{<c>}{<q>} {<Rd>,} <Rn>, <Rm>
d = UInt(Rd); n = UInt(Rn); m = UInt(Rm);
if d == 15 || n == 15 || m == 15 then UNPREDICTABLE; // Armv8-A removes UNPREDICTABLE for R13
<c>
See Standard assembler syntax fields.
<q>
See Standard assembler syntax fields.
<Rd>
Is the general-purpose destination register, encoded in the "Rd" field.
<Rn>
Is the first general-purpose source register, encoded in the "Rn" field.
<Rm>
Is the second general-purpose source register, encoded in the "Rm" field.
if ConditionPassed() then
EncodingSpecificOperations();
sum1 = UInt(R[n]<7:0>) + UInt(R[m]<7:0>);
sum2 = UInt(R[n]<15:8>) + UInt(R[m]<15:8>);
sum3 = UInt(R[n]<23:16>) + UInt(R[m]<23:16>);
sum4 = UInt(R[n]<31:24>) + UInt(R[m]<31:24>);
R[d]<7:0> = UnsignedSat(sum1, 8);
R[d]<15:8> = UnsignedSat(sum2, 8);
R[d]<23:16> = UnsignedSat(sum3, 8);
R[d]<31:24> = UnsignedSat(sum4, 8);