it's a fairly good introduction to AVX though in the "Instruction Set Overview"the author states that "As a result, the VEX instructions can only be used when running in 64-bit mode." I know from first hand experience that this is wrong since my own AVX coderunfine in32-bit mode on a Sandy Bridge CPU. I'll suggest to fix this error in the article since newcomers to AVX may be misled by this.
nice catch, wrong statement for sure, we will fix it, thanks! ... author was close in understanding of LDS/LES opcodes re-use for VEX prefix, but what happens in 32-bit is that VEX prefix, although still using LDS/LES opcodes, always ends up in unsupported forms of these instructions (those with memory operands), thanks to bit-complement encoding of some fields, hence everything is backwards compatible in 32-bit mode too