# SQRTPD — Square Root of Double Precision Floating-Point Values

Opcode/Instruction | Op / En | 64/32 bit Mode Support | CPUID Feature Flag | Description
--- | --- | --- | --- | ---
66 0F 51 /r SQRTPD xmm1, xmm2/m128 | A | V/V | SSE2 | Computes Square Roots of the packed double precision floating-point values in xmm2/m128 and stores the result in xmm1.
VEX.128.66.0F.WIG 51 /r VSQRTPD xmm1, xmm2/m128 | A | V/V | AVX | Computes Square Roots of the packed double precision floating-point values in xmm2/m128 and stores the result in xmm1.
VEX.256.66.0F.WIG 51 /r VSQRTPD ymm1, ymm2/m256 | A | V/V | AVX | Computes Square Roots of the packed double precision floating-point values in ymm2/m256 and stores the result in ymm1.
EVEX.128.66.0F.W1 51 /r VSQRTPD xmm1 {k1}{z}, xmm2/m128/m64bcst | B | V/V | AVX512VL AVX512F | Computes Square Roots of the packed double precision floating-point values in xmm2/m128/m64bcst and stores the result in xmm1 subject to writemask k1.
EVEX.256.66.0F.W1 51 /r VSQRTPD ymm1 {k1}{z}, ymm2/m256/m64bcst | B | V/V | AVX512VL AVX512F | Computes Square Roots of the packed double precision floating-point values in ymm2/m256/m64bcst and stores the result in ymm1 subject to writemask k1.
EVEX.512.66.0F.W1 51 /r VSQRTPD zmm1 {k1}{z}, zmm2/m512/m64bcst{er} | B | V/V | AVX512F | Computes Square Roots of the packed double precision floating-point values in zmm2/m512/m64bcst and stores the result in zmm1 subject to writemask k1.

## Instruction Operand Encoding ¶

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

## Description ¶

Performs a SIMD computation of the square roots of the two, four or eight packed double precision floating-point values in the source operand (the second operand) stores the packed double precision floating-point results in the destination operand (the first operand).

EVEX encoded versions: The source operand is a ZMM/YMM/XMM register, a 512/256/128-bit memory location, or a 512/256/128-bit vector broadcasted from a 64-bit memory location. The destination operand is a ZMM/YMM/XMM register updated according to the writemask.

VEX.256 encoded version: The source operand is a YMM register or a 256-bit memory location. The destination operand is a YMM register. The upper bits (MAXVL-1:256) of the corresponding ZMM register destination are zeroed.

VEX.128 encoded version: the source operand second source operand or a 128-bit memory location. The destination operand is an XMM register. The upper bits (MAXVL-1:128) of the corresponding ZMM register destination are zeroed.

128-bit Legacy SSE version: The second source can be an XMM register or 128-bit memory location. The destination is not distinct from the first source XMM register and the upper bits (MAXVL-1:128) of the corresponding ZMM register destination are unmodified.

Note: VEX.vvvv and EVEX.vvvv are reserved and must be 1111b otherwise instructions will #UD.

## Operation ¶

### VSQRTPD (EVEX Encoded Versions) ¶

    (KL, VL) = (2, 128), (4, 256), (8, 512)
    IF (VL = 512) AND (EVEX.b = 1) AND (SRC *is register*)
        THEN
            SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(EVEX.RC);
        ELSE
            SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(MXCSR.RC);
    FI;
    FOR j := 0 TO KL-1
        i := j * 64
        IF k1[j] OR *no writemask* THEN
                IF (EVEX.b = 1) AND (SRC *is memory*)
                    THEN DEST[i+63:i] := SQRT(SRC[63:0])
                    ELSE DEST[i+63:i] := SQRT(SRC[i+63:i])
                FI;
            ELSE
                IF *merging-masking* ; merging-masking
                    THEN *DEST[i+63:i] remains unchanged*
                    ELSE ; zeroing-masking
                        DEST[i+63:i] := 0
                FI
        FI;
    ENDFOR
    DEST[MAXVL-1:VL] := 0

### VSQRTPD (VEX.256 Encoded Version) ¶

    DEST[63:0] := SQRT(SRC[63:0])
    DEST[127:64] := SQRT(SRC[127:64])
    DEST[191:128] := SQRT(SRC[191:128])
    DEST[255:192] := SQRT(SRC[255:192])
    DEST[MAXVL-1:256] := 0
    .

### VSQRTPD (VEX.128 Encoded Version) ¶

    DEST[63:0] := SQRT(SRC[63:0])
    DEST[127:64] := SQRT(SRC[127:64])
    DEST[MAXVL-1:128] := 0

### SQRTPD (128-bit Legacy SSE Version) ¶

    DEST[63:0] := SQRT(SRC[63:0])
    DEST[127:64] := SQRT(SRC[127:64])
    DEST[MAXVL-1:128] (Unmodified)

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

    VSQRTPD __m512d _mm512_sqrt_round_pd(__m512d a, int r);

    VSQRTPD __m512d _mm512_mask_sqrt_round_pd(__m512d s, __mmask8 k, __m512d a, int r);

    VSQRTPD __m512d _mm512_maskz_sqrt_round_pd( __mmask8 k, __m512d a, int r);

    VSQRTPD __m256d _mm256_sqrt_pd (__m256d a);

    VSQRTPD __m256d _mm256_mask_sqrt_pd(__m256d s, __mmask8 k, __m256d a, int r);

    VSQRTPD __m256d _mm256_maskz_sqrt_pd( __mmask8 k, __m256d a, int r);

    SQRTPD __m128d _mm_sqrt_pd (__m128d a);

    VSQRTPD __m128d _mm_mask_sqrt_pd(__m128d s, __mmask8 k, __m128d a, int r);

    VSQRTPD __m128d _mm_maskz_sqrt_pd( __mmask8 k, __m128d a, int r);

## SIMD Floating-Point Exceptions ¶

Invalid, Precision, Denormal.

## Other Exceptions ¶

Non-EVEX-encoded instruction, see Table 2-19, “Type 2 Class Exception Conditions,” additionally:

#UD | If VEX.vvvv != 1111B.

EVEX-encoded instruction, see Table 2-46, “Type E2 Class Exception Conditions,” additionally:

#UD | If EVEX.vvvv != 1111B.