Age | Commit message (Collapse) | Author | Files | Lines | |
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2012-03-22 | acos.s fix: use the formula acos(x) = atan2(sqrt(1-x),sqrt(1+x)) | nsz | 1 | -3/+1 | |
the old formula atan2(1,sqrt((1+x)/(1-x))) was faster but could give nan result at x=1 when the rounding mode is FE_DOWNWARD (so 1-1 == -0 and 2/-0 == -inf), the new formula gives -0 at x=+-1 with downward rounding. | |||||
2012-03-19 | use alternate formula for acos asm to avoid loss of precision | Rich Felker | 1 | -3/+11 | |
2012-03-19 | asm for inverse trig functions | Rich Felker | 1 | -0/+24 | |
unlike trig functions, these are easy to do in asm because they do not involve (arbitrary-precision) argument reduction. fpatan automatically takes care of domain issues, and in asin and acos, fsqrt takes care of them for us. |