SQRTPD—Compute Square Roots of Packed 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	RM	V/V	SSE2	Computes square roots of the packed doubleprecision floating-point values in xmm2/m128 and stores the results in xmm1.
VEX.128.66.0F.WIG 51 /r VSQRTPD xmm1, xmm2/m128	RM	V/V	AVX	Computes Square Roots of the packed doubleprecision floating-point values in xmm2/m128 and stores the result in xmm1.
VEX.256.66.0F.WIG 51/r VSQRTPD ymm1, ymm2/m256	RM	V/V	AVX	Computes Square Roots of the packed doubleprecision floating-point values in ymm2/m256 and stores the result in ymm1.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RM	ModRM:reg (w)	ModRM:r/m (r)	NA	NA

Description

Performs a SIMD computation of the square roots of the two packed double-precision floating-point values in the source operand (second operand) stores the packed double-precision floating-point results in the destination operand. The source operand can be an XMM register or a 128-bit memory location. The destination operand is an XMM register. See Figure 11-3 in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1, for an illustration of a SIMD double-precision floating-point operation.

In 64-bit mode, using a REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15). 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 (VLMAX-1:128) of the corresponding YMM register destination are unmodified. 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 (VLMAX-1:128) of the corresponding YMM register destination are zeroed. VEX.256 encoded version: The source operand is a YMM register or a 256-bit memory location. The destination operand is a YMM register. Note: In VEX-encoded versions, VEX.vvvv is reserved and must be 1111b otherwise instructions will #UD.

Operation

SQRTPD (128-bit Legacy SSE version)
DEST[63:0] ← SQRT(SRC[63:0])
DEST[127:64] ← SQRT(SRC[127:64])
DEST[VLMAX-1:128] (Unmodified)
VSQRTPD (VEX.128 encoded version)
DEST[63:0] ← SQRT(SRC[63:0])
DEST[127:64] ← SQRT(SRC[127:64])
DEST[VLMAX-1:128] ← 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])

Intel C/C++ Compiler Intrinsic Equivalent

SQRTPD:	__m128d _mm_sqrt_pd (m128d a)
SQRTPD:	__m256d _mm256_sqrt_pd (__m256d a);

SIMD Floating-Point Exceptions

Invalid, Precision, Denormal.

Other Exceptions

See Exceptions Type 2; additionally

#UD	If VEX.vvvv != 1111B.