NASM 2.05 based x86 Instruction Reference[ch170]
A.5.148 MAXPS: Return Packed Single-Precision FP Maximum MAXPS xmm1,xmm2/m128 ; 0F 5F /r [KATMAI,SSE] MAXPS performs a SIMD compare of the packed single-precision FP numbers from xmm1 and xmm2/mem, and stores the maximum values of each pair of values in xmm1. If the values being compared are both zeroes, source2 (xmm2/m128) would be returned. If source2 (xmm2/m128) is an SNaN, this SNaN is forwarded unchanged to the destination (i.e., a QNaN version of the SNaN is not returned).