## subss - subtract scalar single (32 bit floating point)

    dest = dest - source

The subss instruction subtracts the source value (second operand) from the destination (an XMM register). The source can be an XMM register or a 32 bit memory location. There is also vsubss on CPUs with AVX instructions which allows using 3 XMM registers or 2 XMM registers and a memory location which can simplify coding.

            subss   xmm0, xmm1          ; subtract xmm1 from xmm0
                                        ; leave the rest of xmm0 as is
            subss   xmm0, [x]           ; subtract 32 bit variable x from xmm0
                                        ; leave the rest of xmm0 as is
            subss   xmm0, [x+4*rcx]     ; subtract element of array x from xmm0
                                        ; rcx contains the array index
            vsubss  xmm3, xmm0, xmm15   ; xmm3 = xmm0 - xmm15

                ; Note: operates by copying 128 bits from xmm0 to xmm3
                ; before subtracting.  This might occasionally be useful.
                ; The rest of ymm0 is left as is
                ; using subss would change either xmm0 or xmm15
                ; possibly requiring an additional instruction

            vsubss  xmm3, xmm0, [x]     ; xmm3 = xmm0 - x

### flags: none