Blend Packed Double-Precision Floating-Point Values

Encoding

EncodingOperand 1Operand 2Operand 3Operand 4
rmiModRM.reg[rw]ModRM.r/m[r]imm8
rvmiModRM.reg[w]VEX.vvvv[r]ModRM.r/m[r]imm8

Description

The (V)BLENDPD instruction conditionally moves double-precision floating-point values from the two source operands. From the control byte, each bit, if cleared, will move from the first source operand, and, if set, will move from the second source operand. The result is stored in the destination operand.

This instruction, despite being named as if it operates on floating-point numbers, will work on 64 bit integers as well.

All forms except the legacy SSE one will zero the upper (untouched) bits.

Operation

public void BLENDPD(SimdF64 dest, SimdF64 src, U8 mask)
{
    // if `mask.Bit[n]` is 0, `dest` will be copied into itself (i.e. nothing happens)
    if (mask.Bit[0])
        dest[0] = src[0];
    if (mask.Bit[1])
        dest[1] = src[1];
    // dest[2..] is unmodified
}

void VBLENDPD_Vex(SimdF64 dest, SimdF64 src1, SimdF64 src2, U8 mask, int kl)
{
    for (int n = 0; n < kl; n++)
        dest[n] = mask.Bit[n] ? src2[n] : src1[n];
    dest[kl..] = 0;
}
public void VBLENDPD_Vex128(SimdF64 dest, SimdF64 src1, SimdF64 src2, U8 mask) =>
    VBLENDPD_Vex(dest, src1, src2, mask, 2);
public void VBLENDPD_Vex256(SimdF64 dest, SimdF64 src1, SimdF64 src2, U8 mask) =>
    VBLENDPD_Vex(dest, src1, src2, mask, 4);

Intrinsics

Exceptions

SIMD Floating-Point

None.

Other Exceptions

VEX Encoded Form: See Type 4 Exception Conditions.