GBP/USD seesaws in a choppy range between 1.2920/40. AstraZeneca, China data news trigger risk reset. EUR/USD has reversed higher from significant support at 1.1757. Euro bulls may have a hard time holding on to gains. Dollar firms, yen up as tech selloff hits FX. In other markets, DAX futures contract in Germany traded 0.2% higher, CAC 40 futures in France fell 0.2%, while the FTSE 100 futures contract in the U.K. dropped 0.4%.   The sell-off in big tech stocks continued Tuesday, resulting in large losses overnight on Wall Street. The Dow Jones Industrial Average fell 2.3%, or 632 points. The S&P 500 was down 2.8%, while the Nasdaq Composite slumped 4.1% into correction territory, with losses of about 10% in the past three days.  The international benchmark Brent contract trade below $40 a barrel for the first time since late June. U.S. crude futures traded 0.3% lower at $36.66 a barrel, while gold futures fell 0.4% to $1,935.95/oz.