SQRTSD (Intel x86/64 assembly instruction)

모두의 코드
SQRTSD (Intel x86/64 assembly instruction)

작성일 : 2020-09-01 이 글은 867 번 읽혔습니다.

SQRTSD

Compute Square Root of Scalar Double-Precision Floating-Point Value

참고 사항

아래 표를 해석하는 방법은 x86-64 명령어 레퍼런스 읽는 법 글을 참조하시기 바랍니다.

Opcode/ Instruction	Op / En	64/32 bit Mode Support	CPUID Feature Flag	Description
`F2 0F 51/r` SQRTSD xmm1 xmm2/m64	RM	V/V	SSE2	Computes square root of the low double-precision floating-point value in xmm2/m64 and stores the results in xmm1.
`VEX.NDS.128.F2.0F.WIG 51/r` VSQRTSD xmm1 xmm2 xmm3/m64	RVM	V/V	AVX	Computes 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.NDS.LIG.F2.0F.W1 51/r` VSQRTSD xmm1 {k1}{z} xmm2 xmm3/m64{er}	T1S	V/V	AVX512F	Computes square root of the low double-precision floating-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].

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RM	ModRM:reg (w)	ModRM:r/m (r)	NA	NA
RVM	ModRM:reg (w)	VEX.vvvv (r)	ModRM:r/m (r)	NA
T1S	ModRM:reg (w)	EVEX.vvvv (r)	ModRM:r/m (r)	NA

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_RM(EVEX.RC);
    ELSE 
          SET_RM(MXCSR.RM);
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[MAX_VL-1:128] <-  0

VSQRTSD (VEX.128 encoded version)

DEST[63:0] <- SQRT(SRC2[63:0])
DEST[127:64] <- SRC1[127:64]
DEST[MAX_VL-1:128] <- 0

SQRTSD (128-bit Legacy SSE version)

DEST[63:0] <- SQRT(SRC[63:0])
DEST[MAX_VL-1:64] (Unmodified)

Intel C/C++ Compiler Intrinsic Equivalent

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 Exceptions Type 3.

EVEX-encoded instruction, see Exceptions Type E3.

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모두의 코드 SQRTSD (Intel x86/64 assembly instruction)