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Source code

SQRTSD

Compute Square Root of Scalar Double Precision Floating-Point Value

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
F2 0F 51/rSQRTSD xmm1,xmm2/m64AValidValidComputes square root of the low double precision floating- point value in xmm2/m64 and stores the results in xmm1.
VEX.LIG.F2.0F.WIG 51/rVSQRTSD xmm1,xmm2, xmm3/m64BValidValidComputes square root of the low double precision floating- point value in xmm3/m64 and stores the results in xmm1. Also, upper double precision floating-point value (bits[127:64]) from xmm2 is copied to xmm1[127:64].
EVEX.LLIG.F2.0F.W1 51/rVSQRTSD xmm1 {k1}{z}, xmm2, xmm3/m64{er}CValidValidComputes square root of the low double precision floating- OR AVX10.1 point value in xmm3/m64 and stores the results in xmm1 under writemask k1. Also, upper double precision floating- point value (bits[127:64]) from xmm2 is copied to xmm1[127:64].

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

A

  1. modrm.reg escrituraModRM byte, reg field (bits 5-3)
  2. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

B

  1. modrm.reg escrituraModRM byte, reg field (bits 5-3)
  2. vex.vvvv lecturaVEX prefix, vvvv field (inverted)
  3. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

C

  1. modrm.reg escrituraModRM byte, reg field (bits 5-3)
  2. evex.vvvv lecturaEVEX prefix, vvvv field (inverted)
  3. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

Tupla: Tuple1 Scalar

Measured cost

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Description

Computes the square root of the low double precision floating-point value in the second source operand and stores the double precision floating-point result in the destination operand. The second source operand can be an XMM register or a 64-bit memory location. The first source and destination operands are XMM registers.

128-bit Legacy SSE version: The first source operand and the destination operand are the same. The quadword at bits 127:64 of the destination operand remains unchanged. Bits (MAXVL-1:64) of the corresponding destination register remain unchanged.

VEX.128 and EVEX encoded versions: Bits 127:64 of the destination operand are copied from the corresponding bits of the first source operand. Bits (MAXVL-1:128) of the destination register are zeroed.

EVEX encoded version: The low quadword element of the destination operand is updated according to the writemask.

Software should ensure VSQRTSD is encoded with VEX.L=0. Encoding VSQRTSD with VEX.L=1 may encounter unpredictable behavior across different processor generations.

Operation

VSQRTSD (EVEX Encoded Version)

IF (EVEX.b = 1) AND (SRC2 *is register*)

     THEN

     SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(EVEX.RC);

     ELSE

     SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(MXCSR.RC);

FI;

IF k1[0] or *no writemask*

     THEN DEST[63:0] := SQRT(SRC2[63:0])

     ELSE

     IF *merging-masking*                 ; merging-masking

           THEN *DEST[63:0] remains unchanged*

           ELSE                           ; zeroing-masking

           THEN DEST[63:0] := 0

     FI;

FI;

DEST[127:64] := SRC1[127:64]

DEST[MAXVL-1:128] := 0

VSQRTSD (VEX.128 Encoded Version)
DEST[63:0] := SQRT(SRC2[63:0])
DEST[127:64] := SRC1[127:64]
DEST[MAXVL-1:128] := 0

SQRTSD (128-bit Legacy SSE Version)
DEST[63:0] := SQRT(SRC[63:0])
DEST[MAXVL-1:64] (Unmodified)

Intel C/C++ compiler intrinsics

VSQRTSD __m128d _mm_sqrt_round_sd(__m128d a, __m128d b, int r);
VSQRTSD __m128d _mm_mask_sqrt_round_sd(__m128d s, __mmask8 k, __m128d a, __m128d b, int r);
VSQRTSD __m128d _mm_maskz_sqrt_round_sd(__mmask8 k, __m128d a, __m128d b, int r);
SQRTSD __m128d _mm_sqrt_sd (__m128d a, __m128d b);

SIMD Floating-Point Exceptions

Invalid, Precision, Denormal.

Other Exceptions

Non-EVEX-encoded instruction, see Table 2-20, "Type 3 Class Exception Conditions." EVEX-encoded instruction, see Table 2-49, "Type E3 Class Exception Conditions."

Sources