In libm's exp2(3), avoid left-shifting a negative integer, which is
undefined. Replace it with the intended value, in a defined way. Reviewed by: bde MFC after: 3 days
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=286515
@ -376,14 +376,14 @@ exp2(double x)
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/* Compute r = exp2(y) = exp2t[i0] * p(z - eps[i]). */
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t = tbl[i0]; /* exp2t[i0] */
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z -= tbl[i0 + 1]; /* eps[i0] */
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if (k >= -1021 << 20)
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if (k >= -(1021 << 20))
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INSERT_WORDS(twopk, 0x3ff00000 + k, 0);
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else
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INSERT_WORDS(twopkp1000, 0x3ff00000 + k + (1000 << 20), 0);
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r = t + t * z * (P1 + z * (P2 + z * (P3 + z * (P4 + z * P5))));
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/* Scale by 2**(k>>20). */
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if(k >= -1021 << 20) {
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if(k >= -(1021 << 20)) {
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if (k == 1024 << 20)
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return (r * 2.0 * 0x1p1023);
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return (r * twopk);
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