Wireless technology group CSR jumped on rumours that the firm is considering a sale. According to the Financial Times, the UK chipmaker has received takeover offers from a number of rival semiconductor manufacturers and could fetch a price of as much as $3bn, compared with Wednesday's closing price of $1.57bn.Wm Morrison, which rose strongly on Wednesday after industry figures showed an improvement in sales at the UK supermarket, was extending gains as Deutsche Bank upgraded the stock from 'sell' to 'hold'. Tesco, however, was hit with a downgrade from 'buy' to 'hold'.Precious metal producers Randgold Resources and Fresnillo both climbed as gold and silver prices rose on the back of safe-haven demand.Meanwhile, mining stocks Rio Tinto, Anglo American, Antofagasta and BHP Billiton among the worst performers on the blue-chip index as investors scaled back their appetite for risk. Industrial investment firm Melrose was also in the red, despite beating forecasts with its first-half profits, helped by a strong performance from its largest division, Elster.FTSE 100 - RisersCRH (CRH) 1,427.00p +2.07%Morrison (Wm) Supermarkets (MRW) 187.50p +1.68%Tullow Oil (TLW) 733.00p +1.66%Randgold Resources Ltd. (RRS) 5,010.00p +1.40%BT Group (BT.A) 387.80p +1.31%Hammerson (HMSO) 614.00p +1.24%National Grid (NG.) 899.50p +1.24%AstraZeneca (AZN) 4,481.00p +0.72%Diageo (DGE) 1,775.50p +0.71%Severn Trent (SVT) 1,958.00p +0.67%FTSE 100 - FallersHargreaves Lansdown (HL.) 1,124.00p -4.26%Rio Tinto (RIO) 3,209.50p -3.78%St James's Place (STJ) 704.50p -3.49%Anglo American (AAL) 1,519.50p -3.09%BHP Billiton (BLT) 1,894.50p -2.62%Antofagasta (ANTO) 790.00p -2.23%Sports Direct International (SPD) 719.50p -2.11%Petrofac Ltd. (PFC) 1,126.00p -2.00%Carnival (CCL) 2,245.00p -1.66%GKN (GKN) 351.00p -1.63%NR