dest[0] = dest[0] * source[0] dest[1] = dest[1] * source[1]
The mulpd instruction multiplies the 2 source values (second operand) to the 2 values of the destination (an XMM register). The source can be an XMM register or a 64 bit memory location. There is also vmulpd on CPUs with AVX instructions which allows using 3 XMM registers or 2 XMM registers and a memory location which can simplify coding and which multiplies 4 pairs of values if you use YMM registers.
mulpd xmm0, xmm1 ; multiply 2 pairs of values of xmm1 & xmm0 ; leave the rest of ymm0 as is mulpd xmm0, [x] ; multiply 2 pairs of values of x & xmm0 ; x is an array of doubles ; leave the rest of ymm0 as is mulpd xmm0, [x+8*r9] ; multiply 2 pairs from xmm0 & the array x ; r9 contains the first index of x to use ; leave the rest of ymm0 as is vmulpd xmm3, xmm0, xmm15 ; multiply 2 pairs of values of xmm0 & xmm15 ; store results in xmm3 vmulpd ymm3, ymm0, [x] ; multiply 4 pairs of values of ymm0 & x ; x is a double array ; store results in ymm3 vmulpd ymm3, ymm0, [rsi] ; multiply 4 pairs of values of ymm0 & [rsi] ; rsi contains the address of a double array ; store results in ymm3