aglew@ccvaxa.UUCP (07/18/86)
I really hate to admit this, but I've fallen behind in hardware. Sigh. I'm an engineer dammit, not a programmer! Enough tantrums... This is all brought up by not knowing what a "funnel shifter" is, as mentioned in _Electronics_ June 16 (and I also have to admit that I've fallen behind in my reading): "...the new 168-pin 32-bit Am29332 ALU performs more functions than TI's 8832. The 29332 has a funnel shifter, a barrel shifter, and an encoder..." From which I infer that a funnel shifter is not a new, improved barrel shifter, or there would be no need to have them both. A misaligned move unit, perhaps? WHAT IS A FUNNEL SHIFTER? I'd appreciate any comments, email or posted, perhaps with references so that I can find out what the circuits look like. Andy "Krazy" Glew. Gould CSD-Urbana. USEnet: ihnp4!uiucdcs!ccvaxa!aglew 1101 E. University, Urbana, IL 61801 ARPAnet: aglew@gswd-vms
bcase@amdcad.UUCP (07/20/86)
>unit, perhaps? WHAT IS A FUNNEL SHIFTER? >Andy "Krazy" Glew. Gould CSD-Urbana. USEnet: ihnp4!uiucdcs!ccvaxa!aglew >1101 E. University, Urbana, IL 61801 ARPAnet: aglew@gswd-vms A funnel shifter is just a big, stinking mux with 2n inputs and n outputs. Two words are concatenated (i.e. butted up to each other, no this isn't some violation of the recent supreme court ruling) and a single word is chosen for the output starting at some given bit position of the two-word input. Thus, it is easy to effect a barrel shifter by simply supplying the same data in both of the input words. No, there are NOT two shifters on the Am29332, just the one funnel shifter. Another application of the funnel shifter is to extract an unaligned data word from two adjacent, aligned data words. If this isn't sufficiently clear, I can have the 29332 data sheet sent to you.... bcase Product Planning Advanced Micro Devices ------ Is an Oxidized Instruction Set Computer the opposite of a Reduced Instruction Set Computer??? Now I understand!