VFNMSUB132SD/VFNMSUB213SD/VFNMSUB231SD—Fused Negative Multiply-Subtract of Scalar Double-Precision Floating-Point Values

Instruction Operand Encoding

Description

VFNMSUB132SD: Multiplies the low packed double-precision floating-point value from the first source operand to the low packed double-precision floating-point value in the third source operand. From negated infinite precision intermediate result, subtracts the low double-precision floating-point value in the second source operand, performs rounding and stores the resulting packed double-precision floating-point value to the destination operand (first source operand).

VFNMSUB213SD: Multiplies the low packed double-precision floating-point value from the second source operand to the low packed double-precision floating-point value in the first source operand. From negated infinite precision intermediate result, subtracts the low double-precision floating-point value in the third source operand, performs rounding and stores the resulting packed double-precision floating-point value to the destination operand (first source operand).

VFNMSUB231SD: Multiplies the low packed double-precision floating-point value from the second source to the low packed double-precision floating-point value in the third source operand. From negated infinite precision interme-diate result, subtracts the low double-precision floating-point value in the first source operand, performs rounding and stores the resulting packed double-precision floating-point value to the destination operand (first source operand).

VEX.128 and EVEX encoded version: The destination operand (also first source operand) is encoded in reg_field. The second source operand is encoded in VEX.vvvv/EVEX.vvvv. The third source operand is encoded in rm_field. Bits 127:64 of the destination are unchanged. Bits MAXVL-1:128 of the destination register are zeroed.

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

Compiler tools may optionally support a complementary mnemonic for each instruction mnemonic listed in the opcode/instruction column of the summary table. The behavior of the complementary mnemonic in situations involving NANs are governed by the definition of the instruction mnemonic defined in the opcode/instruction column.

Operation

In the operations below, “*” and “-” symbols represent multiplication and subtraction with infinite precision inputs and outputs (no rounding).

VFNMSUB132SD DEST, SRC2, SRC3 (EVEX encoded version)

IF (EVEX.b = 1) and SRC3 *is a register*

THEN

SET_RM(EVEX.RC);

ELSE

SET_RM(MXCSR.RM);

FI;

IF k1[0] or *no writemask*

THEN

DEST[63:0] (cid:197) RoundFPControl(-(DEST[63:0]*SRC3[63:0]) - SRC2[63:0])

ELSE

IF *merging-masking*

; merging-masking

THEN *DEST[63:0] remains unchanged*

ELSE

; zeroing-masking

THEN DEST[63:0] (cid:197) 0

FI;

FI;

DEST[127:64] (cid:197) DEST[127:64]

DEST[MAX_VL-1:128] (cid:197) 0

VFNMSUB213SD DEST, SRC2, SRC3 (EVEX encoded version)

IF (EVEX.b = 1) and SRC3 *is a register*

THEN

SET_RM(EVEX.RC);

ELSE

SET_RM(MXCSR.RM);

FI;

IF k1[0] or *no writemask*

THEN

DEST[63:0] (cid:197) RoundFPControl(-(SRC2[63:0]*DEST[63:0]) - SRC3[63:0])

ELSE

IF *merging-masking*

; merging-masking

THEN *DEST[63:0] remains unchanged*

ELSE

; zeroing-masking

THEN DEST[63:0] (cid:197) 0

FI;

FI;

DEST[127:64] (cid:197) DEST[127:64]

DEST[MAX_VL-1:128] (cid:197) 0

VFNMSUB231SD DEST, SRC2, SRC3 (EVEX encoded version)

IF (EVEX.b = 1) and SRC3 *is a register*

THEN

SET_RM(EVEX.RC);

ELSE

SET_RM(MXCSR.RM);

FI;

IF k1[0] or *no writemask*

THEN

DEST[63:0] (cid:197) RoundFPControl(-(SRC2[63:0]*SRC3[63:0]) - DEST[63:0])

ELSE

IF *merging-masking*

; merging-masking

THEN *DEST[63:0] remains unchanged*

ELSE

; zeroing-masking

THEN DEST[63:0] (cid:197) 0

FI;

FI;

DEST[127:64] (cid:197) DEST[127:64]

DEST[MAX_VL-1:128] (cid:197) 0

VFNMSUB132SD DEST, SRC2, SRC3 (VEX encoded version)

DEST[63:0] (cid:197)RoundFPControl_MXCSR(- (DEST[63:0]*SRC3[63:0]) - SRC2[63:0])

DEST[127:64] (cid:197)DEST[127:64]

DEST[MAX_VL-1:128] (cid:197)0

VFNMSUB213SD DEST, SRC2, SRC3 (VEX encoded version)

DEST[63:0] (cid:197)RoundFPControl_MXCSR(- (SRC2[63:0]*DEST[63:0]) - SRC3[63:0])

DEST[127:64] (cid:197)DEST[127:64]

DEST[MAX_VL-1:128] (cid:197)0

VFNMSUB231SD DEST, SRC2, SRC3 (VEX encoded version)

DEST[63:0] (cid:197)RoundFPControl_MXCSR(- (SRC2[63:0]*SRC3[63:0]) - DEST[63:0])

DEST[127:64] (cid:197)DEST[127:64]

DEST[MAX_VL-1:128] (cid:197)0

Intel C/C++ Compiler Intrinsic Equivalent

VFNMSUBxxxSD __m128d _mm_fnmsub_round_sd(__m128d a, __m128d b, __m128d c, int r);

VFNMSUBxxxSD __m128d _mm_mask_fnmsub_sd(__m128d a, __mmask8 k, __m128d b, __m128d c);

VFNMSUBxxxSD __m128d _mm_maskz_fnmsub_sd(__mmask8 k, __m128d a, __m128d b, __m128d c);

VFNMSUBxxxSD __m128d _mm_mask3_fnmsub_sd(__m128d a, __m128d b, __m128d c, __mmask8 k);

VFNMSUBxxxSD __m128d _mm_mask_fnmsub_round_sd(__m128d a, __mmask8 k, __m128d b, __m128d c, int r);

VFNMSUBxxxSD __m128d _mm_maskz_fnmsub_round_sd(__mmask8 k, __m128d a, __m128d b, __m128d c, int r);

VFNMSUBxxxSD __m128d _mm_mask3_fnmsub_round_sd(__m128d a, __m128d b, __m128d c, __mmask8 k, int r);

VFNMSUBxxxSD __m128d _mm_fnmsub_sd (__m128d a, __m128d b, __m128d c);

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal

Other Exceptions