tc (12/15/82)
FUNCTION Am9511(4Mhz) Am9512(3Mhz) 8087 8086 Data Formats: Floating Not IEEE Almost IEEE IEEE Fixed 16/32 n/a 8/16/32/64 BCD n/a n/a 18 digits Interface: Peripheral Peripheral Co-Processor Timing (Floating Point Operations) Add/Sub 22 usec 42 usec 17 usec 1600 usec 32-bit Mult 37 150 19 1600 32-bit Div 44 170 39 3200 Load (programmed) (programmed) 10 1700 Store (programmed) (programmed) 21 1200 SQRT 200 n/a 36 19600 TAN 1400 n/a 90 13000 $$$$(approx) 195 165 150 COMMENTARY 0. The times for the 8086 and 8087 are from the 1982 Intel Component Data Catalog, page 8-72. The times for the AM9511 and 9512 are from the AMD data sheets. 1. The Am9511 and Am9512 are easy to interface to nearly any processor or bus. If you can figure out to hook up a UART (say 8251), you can do the 9511 or 9512. 2. Somebody asked about 9511's having problems with negative numbers. I don't think so. Please point me to the reference. 3. The 8087 does not have all the trig functions build in; you have to derive them from Partial Tangent and Partial Arctangent. The 9511 does have lots of trig functions and the 9512 doesnt even pretend. 4. If I were interfacing to an 8086 or 8088, I would choose the 8087. If I were interfacing to anything else, I would choose the 9511. Tom Crawford (...ucbvax!adm70!tc)