# VFCMULCSH/VFMULCSH — Complex Multiply 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.F2.MAP6.W0 D7 /r VFCMULCSH xmm1{k1}{z}, xmm2, xmm3/m32 {er} | A | V/V | AVX512-FP16 | Complex multiply a pair of FP16 values from xmm2 and complex conjugate of xmm3/m32, and store the result in xmm1 subject to writemask k1. Bits 127:32 of xmm2 are copied to xmm1[127:32].
EVEX.LLIG.F3.MAP6.W0 D7 /r VFMULCSH xmm1{k1}{z}, xmm2, xmm3/m32 {er} | A | V/V | AVX512-FP16 | Complex multiply a pair of FP16 values from xmm2 and xmm3/m32, and store the result in xmm1 subject to writemask k1. Bits 127:32 of xmm2 are copied to xmm1[127:32].

## Instruction Operand Encoding ¶

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

### Description ¶

This instruction performs a complex multiply operation. There are normal and complex conjugate forms of the operation. The masking for this operation is done on 32-bit quantities representing a pair of FP16 values.

Bits 127:32 of the destination operand are copied from the corresponding bits of the first source operand. Bits MAXVL-1:128 of the destination operand are zeroed. The low FP16 element of the destination is updated according to the writemask.

Rounding is performed at every FMA (fused multiply and add) boundary. Execution occurs as if all MXCSR exceptions are masked. MXCSR status bits are updated to reflect exceptional conditions.

### Operation ¶

#### VFCMULCSH dest{k1}, src1, src2 (AVX512) ¶

    KL := VL / 32
    IF k1[0] or *no writemask*:
        tmp.fp16[0] := src1.fp16[0] * src2.fp16[0]
        tmp.fp16[1] := src1.fp16[1] * src2.fp16[0]
        // conjugate version subtracts odd final term
        dest.fp16[0] := tmp.fp16[0] + src1.fp16[1] * src2.fp16[1]
        dest.fp16[1] := tmp.fp16[1] - src1.fp16[0] * src2.fp16[1]
    ELSE IF *zeroing*:
        dest.fp16[0] := 0
        dest.fp16[1] := 0
    DEST[127:32] := src1[127:32] // copy upper part of src1
    DEST[MAXVL-1:128] := 0

#### VFMULCSH dest{k1}, src1, src2 (AVX512) ¶

    KL := VL / 32
    IF k1[0] or *no writemask*:
        // non-conjugate version subtracts last even term
        tmp.fp16[0] := src1.fp16[0] * src2.fp16[0]
        tmp.fp16[1] := src1.fp16[1] * src2.fp16[0]
        dest.fp16[0] := tmp.fp16[0] - src1.fp16[1] * src2.fp16[1]
        dest.fp16[1] := tmp.fp16[1] + src1.fp16[0] * src2.fp16[1]
    ELSE IF *zeroing*:
        dest.fp16[0] := 0
        dest.fp16[1] := 0
    DEST[127:32] := src1[127:32] // copy upper part of src1
    DEST[MAXVL-1:128] := 0

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

    VFCMULCSH __m128h _mm_cmul_round_sch (__m128h a, __m128h b, const int rounding);

    VFCMULCSH __m128h _mm_mask_cmul_round_sch (__m128h src, __mmask8 k, __m128h a, __m128h b, const int rounding);

    VFCMULCSH __m128h _mm_maskz_cmul_round_sch (__mmask8 k, __m128h a, __m128h b, const int rounding);

    VFCMULCSH __m128h _mm_cmul_sch (__m128h a, __m128h b);

    VFCMULCSH __m128h _mm_mask_cmul_sch (__m128h src, __mmask8 k, __m128h a, __m128h b);

    VFCMULCSH __m128h _mm_maskz_cmul_sch (__mmask8 k, __m128h a, __m128h b);

    VFCMULCSH __m128h _mm_fcmul_round_sch (__m128h a, __m128h b, const int rounding);

    VFCMULCSH __m128h _mm_mask_fcmul_round_sch (__m128h src, __mmask8 k, __m128h a, __m128h b, const int rounding);

    VFCMULCSH __m128h _mm_maskz_fcmul_round_sch (__mmask8 k, __m128h a, __m128h b, const int rounding);

    VFCMULCSH __m128h _mm_fcmul_sch (__m128h a, __m128h b);

    VFCMULCSH __m128h _mm_mask_fcmul_sch (__m128h src, __mmask8 k, __m128h a, __m128h b);

    VFCMULCSH __m128h _mm_maskz_fcmul_sch (__mmask8 k, __m128h a, __m128h b);

    VFMULCSH __m128h _mm_fmul_round_sch (__m128h a, __m128h b, const int rounding);

    VFMULCSH __m128h _mm_mask_fmul_round_sch (__m128h src, __mmask8 k, __m128h a, __m128h b, const int rounding);

    VFMULCSH __m128h _mm_maskz_fmul_round_sch (__mmask8 k, __m128h a, __m128h b, const int rounding);

    VFMULCSH __m128h _mm_fmul_sch (__m128h a, __m128h b);

    VFMULCSH __m128h _mm_mask_fmul_sch (__m128h src, __mmask8 k, __m128h a, __m128h b);

    VFMULCSH __m128h _mm_maskz_fmul_sch (__mmask8 k, __m128h a, __m128h b);

    VFMULCSH __m128h _mm_mask_mul_round_sch (__m128h src, __mmask8 k, __m128h a, __m128h b, const int rounding);

    VFMULCSH __m128h _mm_maskz_mul_round_sch (__mmask8 k, __m128h a, __m128h b, const int rounding);

    VFMULCSH __m128h _mm_mul_round_sch (__m128h a, __m128h b, const int rounding);

    VFMULCSH __m128h _mm_mask_mul_sch (__m128h src, __mmask8 k, __m128h a, __m128h b);

    VFMULCSH __m128h _mm_maskz_mul_sch (__mmask8 k, __m128h a, __m128h b);

    VFMULCSH __m128h _mm_mul_sch (__m128h a, __m128h b);

### SIMD Floating-Point Exceptions ¶

Invalid, Underflow, Overflow, Precision, Denormal.

### Other Exceptions ¶

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

Additionally:

#UD | If (dest_reg == src1_reg) or (dest_reg == src2_reg).