Following Thursday’s admission that it is likely facing an operating loss for the current quarter, only one major investment bank downgraded Advanced Micro Devices Inc’s stock, with Donaldson, Lufkin and Jenrette dropping its rating from buy to market perform. Credit Suisse First Boston, while maintaining its hold rating, hacked its earnings per share estimate for 1999 all the way down to $0.05 from $0.20. In research notes published Friday, analysts at CSFB called the companies outlook grim until the K7 chip debuts in volume, which is not expected to happen until the third quarter. AMD shares fell more than 11% Friday, dropping $2.125 to close at $16.813.