knotb
NOT Mask Byte
KNOTB k1, k2
Bitwise NOT of 8-bit mask.
Details
Performs a bitwise NOT of the 8-bit content of the source mask register, storing the result in the destination mask register. Only the lower 8 bits are affected; other bits are zeroed. No flags are affected; this is an AVX-512DQ instruction that operates only on opmask registers (k0–k7).
Pseudocode Operation
dest ← (~src) & 0xFF;Example
KNOTB k1, k2
Encoding
Binary Layout
EVEX
+0
0F
+4
44
+5
Operands
-
dest
AVX-512 opmask register (k0-k7) -
src
AVX-512 opmask register (k0-k7)
Reference (Intel® SDM)
Instruction Forms
| Opcode | Instruction | Op/En | 64/32-bit Mode | CPUID | Description |
|---|---|---|---|---|---|
| VEX.L0.0F.W0 44 /r | KNOTW k1, k2 | V/V | RR AVX512F OR AVX10.1 | Bitwise NOT of 16 bits mask k2. | |
| VEX.L0.66.0F.W0 44 /r | KNOTB k1, k2 | V/V | RR AVX512DQ OR AVX10.1 | Bitwise NOT of 8 bits mask k2. | |
| VEX.L0.0F.W1 44 /r | KNOTQ k1, k2 | V/V | RR AVX512BW OR AVX10.1 | Bitwise NOT of 64 bits mask k2. | |
| VEX.L0.66.0F.W1 44 /r | KNOTD k1, k2 | V/V | RR AVX512BW OR AVX10.1 | Bitwise NOT of 32 bits mask k2. |
Description
Performs a bitwise NOT of vector mask k2 and writes the result into vector mask k1.
Operation
KNOTW DEST[15:0] := BITWISE NOT SRC[15:0] DEST[MAX_KL-1:16] := 0 KNOTB DEST[7:0] := BITWISE NOT SRC[7:0] DEST[MAX_KL-1:8] := 0 KNOTQ DEST[63:0] := BITWISE NOT SRC[63:0] DEST[MAX_KL-1:64] := 0 KNOTD DEST[31:0] := BITWISE NOT SRC[31:0] DEST[MAX_KL-1:32] := 0
Intel C/C++ Compiler Intrinsic Equivalent
KNOTW __mmask16 _mm512_knot(__mmask16 a);
Flags Affected
None.
Exceptions
SIMD Floating-Point Exceptions
None.
Other Exceptions
See Table 2-65, “TYPE K20 Exception Definition (VEX-Encoded OpMask Instructions w/o Memory Arg).”
KNOTW/KNOTB/KNOTQ/KNOTD—NOT Mask Register Vol. 2A 3-519