MULSS (Intel x86/64 assembly instruction)

모두의 코드
MULSS (Intel x86/64 assembly instruction)

작성일 : 2020-09-01 이 글은 1316 번 읽혔습니다.

MULSS

Multiply Scalar Single-Precision Floating-Point Values

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
`F3 0F 59 /r` MULSS xmm1 xmm2/m32	RM	V/V	SSE	Multiply the low single-precision floating-point value in xmm2/m32 by the low single-precision floating-point value in xmm1.
`VEX.NDS.128.F3.0F.WIG 59 /r` VMULSS xmm1 xmm2 xmm3/m32	RVM	V/V	AVX	Multiply the low single-precision floating-point value in xmm3/m32 by the low single-precision floating-point value in xmm2.
`EVEX.NDS.LIG.F3.0F.W0 59 /r` VMULSS xmm1 {k1}{z} xmm2 xmm3/m32 {er}	T1S	V/V	AVX512F	Multiply the low single-precision floating-point value in xmm3/m32 by the low single-precision floating-point value in xmm2.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RM	ModRM:reg (r, 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

Multiplies the low single-precision floating-point value from the second source operand by the low single-precision floating-point value in the first source operand, and stores the single-precision floating-point result in the destina-tion operand. The second source operand can be an XMM register or a 32-bit memory location. The first source operand and the destination operands are XMM registers.

128-bit Legacy SSE version: The first source operand and the destination operand are the same. Bits (MAXVL-1:32) of the corresponding YMM destination register remain unchanged.

VEX.128 and EVEX encoded version: The first source operand is an xmm register encoded by VEX.vvvv. The three high-order doublewords of the destination operand are copied from the first source operand. Bits (MAXVL-1:128) of the destination register are zeroed.

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

Software should ensure VMULSS is encoded with VEX.L=0. Encoding VMULSS with VEX.L=1 may encounter unpre-dictable behavior across different processor generations.

Operation

VMULSS (EVEX encoded version)

IF (EVEX.b = 1) AND SRC2 *is a register*
    THEN
          SET_RM(EVEX.RC);
    ELSE 
          SET_RM(MXCSR.RM);
FI;
IF k1[0] or *no writemask*
    THEN DEST[31:0] <-  SRC1[31:0] * SRC2[31:0]
    ELSE 
          IF *merging-masking* ; merging-masking
                THEN *DEST[31:0] remains unchanged*
                ELSE  ; zeroing-masking
                      THEN DEST[31:0] <-  0
                FI
    FI;
ENDFOR
DEST[127:32] <-  SRC1[127:32]
DEST[MAX_VL-1:128] <-  0

VMULSS (VEX.128 encoded version)

DEST[31:0] <- SRC1[31:0] * SRC2[31:0]
DEST[127:32] <- SRC1[127:32]
DEST[MAX_VL-1:128] <- 0

MULSS (128-bit Legacy SSE version)

DEST[31:0] <- DEST[31:0] * SRC[31:0]
DEST[MAX_VL-1:32] (Unmodified)

Intel C/C++ Compiler Intrinsic Equivalent

VMULSS __m128 _mm_mask_mul_ss(__m128 s, __mmask8 k, __m128 a, __m128 b);
VMULSS __m128 _mm_maskz_mul_ss(__mmask8 k, __m128 a, __m128 b);
VMULSS __m128 _mm_mul_round_ss(__m128 a, __m128 b, int);
VMULSS __m128 _mm_mask_mul_round_ss(__m128 s, __mmask8 k, __m128 a, __m128 b,
                                    int);
VMULSS __m128 _mm_maskz_mul_round_ss(__mmask8 k, __m128 a, __m128 b, int);
MULSS __m128 _mm_mul_ss(__m128 a, __m128 b)

SIMD Floating-Point Exceptions

Underflow, Overflow, 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 MULSS (Intel x86/64 assembly instruction)