# VFPCLASSSH — Test Types of Scalar FP16 Values

Instruction En Bit Mode Flag Support Instruction En Bit Mode Flag Support 64/32 CPUID Feature Instruction En Bit Mode Flag CPUID Feature Instruction En Bit Mode Flag Op/ 64/32 CPUID Feature Instruction En Bit Mode Flag 64/32 CPUID Feature Instruction En Bit Mode Flag CPUID Feature Instruction En Bit Mode Flag Op/ 64/32 CPUID Feature |  | Support |  | Description
--- | --- | --- | --- | ---
EVEX.LLIG.NP.0F3A.W0 67 /r /ib VFPCLASSSH k1{k2}, xmm1/m16, imm8 | A | V/V | AVX512-FP16 | Test the input for the following categories: NaN, +0, -0, +Infinity, -Infinity, denormal, finite negative. The immediate field provides a mask bit for each of these category tests. The masked test results are OR-ed together to form a mask result.

## Instruction Operand Encoding ¶

Op/En | Tuple | Operand 1 | Operand 2 | Operand 3 | Operand 4
--- | --- | --- | --- | --- | ---
A | Scalar | ModRM:reg (w) | ModRM:r/m (r) | imm8 (r) | N/A

### Description ¶

This instruction checks the low FP16 value in the source operand for special categories, specified by the set bits in the imm8 byte. Each set bit in imm8 specifies a category of floating-point values that the input data element is classified against; see Table 5-9 for the categories. The classified results of all specified categories of an input value are ORed together to form the final boolean result for the input element. The result is written to the low bit in the destination mask register according to the writemask. The other bits in the destination mask register are zeroed.

### Operation ¶

#### VFPCLASSSH dest{k2}, src, imm8 ¶

    IF k2[0] or *no writemask*:
        DEST.bit[0] := check_fp_class_fp16(src.fp16[0], imm8)
            // see VFPCLASSPH
    ELSE:
        DEST.bit[0] := 0
    DEST[MAXKL-1:1] := 0

### Intel C/C++ Compiler Intrinsic Equivalent ¶

    VFPCLASSSH __mmask8 _mm_fpclass_sh_mask (__m128h a, int imm8);

    VFPCLASSSH __mmask8 _mm_mask_fpclass_sh_mask (__mmask8 k1, __m128h a, int imm8);

### SIMD Floating-Point Exceptions ¶

None.

### Other Exceptions ¶

EVEX-encoded instructions, see Table 2-58, “Type E10 Class Exception Conditions.”