VFMSUB132PS/VFMSUB213PS/VFMSUB231PS—Fused Multiply-Subtract of Packed Single-Precision Floating-Point Values

Instruction Operand Encoding

Description

Performs a set of SIMD multiply-subtract computation on packed single-precision floating-point values using three source operands and writes the multiply-subtract results in the destination operand. The destination operand is also the first source operand. The second operand must be a SIMD register. The third source operand can be a SIMD register or a memory location.

VFMSUB132PS: Multiplies the four, eight or sixteen packed single-precision floating-point values from the first source operand to the four, eight or sixteen packed single-precision floating-point values in the third source operand. From the infinite precision intermediate result, subtracts the four, eight or sixteen packed single-precision floating-point values in the second source operand, performs rounding and stores the resulting four, eight or sixteen packed single-precision floating-point values to the destination operand (first source operand).

VFMSUB213PS: Multiplies the four, eight or sixteen packed single-precision floating-point values from the second source operand to the four, eight or sixteen packed single-precision floating-point values in the first source operand. From the infinite precision intermediate result, subtracts the four, eight or sixteen packed single-precision floating-point values in the third source operand, performs rounding and stores the resulting four, eight or sixteen packed single-precision floating-point values to the destination operand (first source operand).

VFMSUB231PS: Multiplies the four, eight or sixteen packed single-precision floating-point values from the second source to the four, eight or sixteen packed single-precision floating-point values in the third source operand. From the infinite precision intermediate result, subtracts the four, eight or sixteen packed single-precision floating-point values in the first source operand, performs rounding and stores the resulting four, eight or sixteen packed single-precision floating-point values to the destination operand (first source operand).

EVEX encoded versions: The destination operand (also first source operand) and the second source operand are ZMM/YMM/XMM register. The third source operand is a ZMM/YMM/XMM register, a 512/256/128-bit memory loca-tion or a 512/256/128-bit vector broadcasted from a 32-bit memory location. The destination operand is condition-ally updated with write mask k1.

VEX.256 encoded version: The destination operand (also first source operand) is a YMM register and encoded in reg_field. The second source operand is a YMM register and encoded in VEX.vvvv. The third source operand is a YMM register or a 256-bit memory location and encoded in rm_field.

VEX.128 encoded version: The destination operand (also first source operand) is a XMM register and encoded in reg_field. The second source operand is a XMM register and encoded in VEX.vvvv. The third source operand is a XMM register or a 128-bit memory location and encoded in rm_field. The upper 128 bits of the YMM destination register are zeroed.

Operation

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

IF (VEX.128) THEN
    MAXNUM (cid:197)2
    ELSEIF (VEX.256)
    MAXNUM (cid:197) 4
FI
For i = 0 to MAXNUM-1 {
n (cid:197) 32*i;
DEST[n+31:n] (cid:197) RoundFPControl_MXCSR(DEST[n+31:n]*SRC3[n+31:n] - SRC2[n+31:n])
}
IF (VEX.128) THEN
    DEST[MAX_VL-1:128] (cid:197) 0
    ELSEIF (VEX.256)
    DEST[MAX_VL-1:256] (cid:197) 0
FI

IF (VEX.128) THEN
    MAXNUM (cid:197)2
    ELSEIF (VEX.256)
    MAXNUM (cid:197) 4
FI
For i = 0 to MAXNUM-1 {
n (cid:197) 32*i;
DEST[n+31:n] (cid:197) RoundFPControl_MXCSR(SRC2[n+31:n]*DEST[n+31:n] - SRC3[n+31:n])
}
IF (VEX.128) THEN
    DEST[MAX_VL-1:128] (cid:197) 0
    ELSEIF (VEX.256)
    DEST[MAX_VL-1:256] (cid:197) 0
FI

IF (VEX.128) THEN
    MAXNUM (cid:197)2
    ELSEIF (VEX.256)
    MAXNUM (cid:197) 4
FI
For i = 0 to MAXNUM-1 {
n (cid:197) 32*i;
DEST[n+31:n] (cid:197) RoundFPControl_MXCSR(SRC2[n+31:n]*SRC3[n+31:n] - DEST[n+31:n])
}
IF (VEX.128) THEN
    DEST[MAX_VL-1:128] (cid:197) 0
    ELSEIF (VEX.256)
    DEST[MAX_VL-1:256] (cid:197) 0
FI

(KL, VL) = (4, 128), (8, 256), (16, 512)
IF (VL = 512) AND (EVEX.b = 1)
    THEN
    SET_RM(EVEX.RC);
    ELSE
    SET_RM(MXCSR.RM);
FI;
FOR j (cid:197) 0 TO KL-1
    i (cid:197) j * 32
    IF k1[j] OR *no writemask*
        THEN DEST[i+31:i] (cid:197)
        RoundFPControl(DEST[i+31:i]*SRC3[i+31:i] - SRC2[i+31:i])
        ELSE
        IF *merging-masking*
            ; merging-masking
            THEN *DEST[i+31:i] remains unchanged*
            ELSE
            ; zeroing-masking
            DEST[i+31:i] (cid:197) 0
        FI
    FI;
ENDFOR
DEST[MAX_VL-1:VL] (cid:197) 0

(KL, VL) = (4, 128), (8, 256), (16, 512)
FOR j (cid:197) 0 TO KL-1
    i (cid:197) j * 32
    IF k1[j] OR *no writemask*
        THEN
        IF (EVEX.b = 1)
            THEN
            DEST[i+31:i] (cid:197)
            RoundFPControl_MXCSR(DEST[i+31:i]*SRC3[31:0] - SRC2[i+31:i])
            ELSE
            DEST[i+31:i] (cid:197)
            RoundFPControl_MXCSR(DEST[i+31:i]*SRC3[i+31:i] - SRC2[i+31:i])
        FI;
        ELSE
        IF *merging-masking*
            ; merging-masking
            THEN *DEST[i+31:i] remains unchanged*
            ELSE
            ; zeroing-masking
            DEST[i+31:i] (cid:197) 0
        FI
    FI;
ENDFOR
DEST[MAX_VL-1:VL] (cid:197) 0

(KL, VL) = (4, 128), (8, 256), (16, 512)
IF (VL = 512) AND (EVEX.b = 1)
    THEN
    SET_RM(EVEX.RC);
    ELSE
    SET_RM(MXCSR.RM);
FI;
FOR j (cid:197) 0 TO KL-1
    i (cid:197) j * 32
    IF k1[j] OR *no writemask*
        THEN DEST[i+31:i] (cid:197)
        RoundFPControl_MXCSR(SRC2[i+31:i]*DEST[i+31:i] - SRC3[i+31:i])
        ELSE
        IF *merging-masking*
            ; merging-masking
            THEN *DEST[i+31:i] remains unchanged*
            ELSE
            ; zeroing-masking
            DEST[i+31:i] (cid:197) 0
        FI
    FI;
ENDFOR
DEST[MAX_VL-1:VL] (cid:197) 0

(KL, VL) = (4, 128), (8, 256), (16, 512)
FOR j (cid:197) 0 TO KL-1
    i (cid:197) j * 32
    IF k1[j] OR *no writemask*
        THEN
        IF (EVEX.b = 1)
            THEN
            DEST[i+31:i] (cid:197)
            RoundFPControl_MXCSR(SRC2[i+31:i]*DEST[i+31:i] - SRC3[31:0])
            ELSE
            DEST[i+31:i] (cid:197)
            RoundFPControl_MXCSR(SRC2[i+31:i]*DEST[i+31:i] - SRC3[i+31:i])
        FI;
        ELSE
        IF *merging-masking*
            ; merging-masking
            THEN *DEST[i+31:i] remains unchanged*
            ELSE
            ; zeroing-masking
            DEST[i+31:i] (cid:197) 0
        FI
    FI;
ENDFOR
DEST[MAX_VL-1:VL] (cid:197) 0

(KL, VL) = (4, 128), (8, 256), (16, 512)
IF (VL = 512) AND (EVEX.b = 1)
    THEN
    SET_RM(EVEX.RC);
    ELSE
    SET_RM(MXCSR.RM);
FI;
FOR j (cid:197) 0 TO KL-1
    i (cid:197) j * 32
    IF k1[j] OR *no writemask*
        THEN DEST[i+31:i] (cid:197)
        RoundFPControl_MXCSR(SRC2[i+31:i]*SRC3[i+31:i] - DEST[i+31:i])
        ELSE
        IF *merging-masking*
            ; merging-masking
            THEN *DEST[i+31:i] remains unchanged*
            ELSE
            ; zeroing-masking
            DEST[i+31:i] (cid:197) 0
        FI
    FI;
ENDFOR
DEST[MAX_VL-1:VL] (cid:197) 0

(KL, VL) = (4, 128), (8, 256), (16, 512)
FOR j (cid:197) 0 TO KL-1
    i (cid:197) j * 32
    IF k1[j] OR *no writemask*
        THEN
        IF (EVEX.b = 1)
            THEN
            DEST[i+31:i] (cid:197)
            RoundFPControl_MXCSR(SRC2[i+31:i]*SRC3[31:0] - DEST[i+31:i])
            ELSE
            DEST[i+31:i] (cid:197)
            RoundFPControl_MXCSR(SRC2[i+31:i]*SRC3[i+31:i] - DEST[i+31:i])
        FI;
        ELSE
        IF *merging-masking*
            ; merging-masking
            THEN *DEST[i+31:i] remains unchanged*
            ELSE
            ; zeroing-masking
            DEST[i+31:i] (cid:197) 0
        FI
    FI;
ENDFOR
DEST[MAX_VL-1:VL] (cid:197) 0

Intel C/C++ Compiler Intrinsic Equivalent

VFMSUBxxxPS __m512 _mm512_fmsub_ps(__m512 a, __m512 b, __m512 c);
VFMSUBxxxPS __m512 _mm512_fmsub_round_ps(__m512 a, __m512 b, __m512 c, int r);
VFMSUBxxxPS __m512 _mm512_mask_fmsub_ps(__m512 a, __mmask16 k, __m512 b, __m512 c);
VFMSUBxxxPS __m512 _mm512_maskz_fmsub_ps(__mmask16 k, __m512 a, __m512 b, __m512 c);
VFMSUBxxxPS __m512 _mm512_mask3_fmsub_ps(__m512 a, __m512 b, __m512 c, __mmask16 k);
VFMSUBxxxPS __m512 _mm512_mask_fmsub_round_ps(__m512 a, __mmask16 k, __m512 b, __m512 c, int r);
VFMSUBxxxPS __m512 _mm512_maskz_fmsub_round_ps(__mmask16 k, __m512 a, __m512 b, __m512 c, int r);
VFMSUBxxxPS __m512 _mm512_mask3_fmsub_round_ps(__m512 a, __m512 b, __m512 c, __mmask16 k, int r);
VFMSUBxxxPS __m256 _mm256_mask_fmsub_ps(__m256 a, __mmask8 k, __m256 b, __m256 c);
VFMSUBxxxPS __m256 _mm256_maskz_fmsub_ps(__mmask8 k, __m256 a, __m256 b, __m256 c);
VFMSUBxxxPS __m256 _mm256_mask3_fmsub_ps(__m256 a, __m256 b, __m256 c, __mmask8 k);
VFMSUBxxxPS __m128 _mm_mask_fmsub_ps(__m128 a, __mmask8 k, __m128 b, __m128 c);
VFMSUBxxxPS __m128 _mm_maskz_fmsub_ps(__mmask8 k, __m128 a, __m128 b, __m128 c);
VFMSUBxxxPS __m128 _mm_mask3_fmsub_ps(__m128 a, __m128 b, __m128 c, __mmask8 k);
VFMSUBxxxPS __m128 _mm_fmsub_ps (__m128 a, __m128 b, __m128 c);
VFMSUBxxxPS __m256 _mm256_fmsub_ps (__m256 a, __m256 b, __m256 c);

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal

Other Exceptions