Chip designer ARM Holdings was the worst top-tier performer of the day on Monday after Samsung confirmed that it would use an Intel processor in its new Galaxy tablets, a sharp blow to ARM whose chips had previously powered some of the South Korean firm's devices.ARM investors were shrugging off the news that the company has launched a new range of processing technology, which it hopes will become the chip of choice for the 580m mid-range mobile devices over the new two years.Supermarket group Tesco was also in the red ahead of its first-quarter trading update on Wednesday, as Investec reiterated its 'sell' rating for the stock. The broker said that the statement this week will likely disappoint, with like-for-like sales growth expected to be negative in the UK, Asia and in Europe. "Tesco is not a growth stock, nor is it an income stock and it lacks momentum," said analyst Dave McCarthy.Mining stocks held up well today in spite of a downwards revision to Chinese manufacturing activity by HSBC, which suggested that the sector contracted at a faster-than-expected rate in May. However, these figures continue to contrast with the official government readings which showed steady expansion last month.Vedanta Resources and Glencore Xstrata were among the best performers, making headlines after both were rumoured to be potential bidders for fellow miner Rio Tinto's 59% stake in Iron Ore Company of Canada, which could fetch up to $4.0bn.Gold miner Polymetal International also rose after JPMorgan Cazenove upgraded its rating for the stock from 'neutral' to 'overweight', citing an EPS inflection point next year following the sharp falls in the gold price earlier this year.Food group Tate & Lyle was in demand after Jefferies kept a 'buy' rating, saying that the market is under appreciating the growth potential of its Speciality Food Ingredients division. In contrast, electricity provider Centrica was a heavy faller after Berenberg cut its rating to 'hold'.FTSE 100 - RisersVedanta Resources (VED) 1,290.00p +2.22%Antofagasta (ANTO) 963.00p +1.85%Tullow Oil (TLW) 1,062.00p +1.63%Associated British Foods (ABF) 1,841.00p +1.60%Evraz (EVR) 137.40p +1.55%Polymetal International (POLY) 700.50p +1.45%Johnson Matthey (JMAT) 2,598.00p +1.44%Kingfisher (KGF) 349.90p +1.24%Glencore Xstrata (GLEN) 326.90p +1.18%Tate & Lyle (TATE) 826.00p +1.16%FTSE 100 - FallersARM Holdings (ARM) 949.00p -3.95%Tesco (TSCO) 356.15p -2.54%easyJet (EZJ) 1,234.00p -2.53%Aggreko (AGK) 1,746.00p -2.29%Centrica (CNA) 371.50p -2.24%Carnival (CCL) 2,197.00p -2.14%Aberdeen Asset Management (ADN) 456.40p -2.06%BT Group (BT.A) 296.00p -2.02%SSE (SSE) 1,524.00p -1.93%William Hill (WMH) 434.50p -1.85%