1 // SPDX-License-Identifier: GPL-2.0-only
7  * Copyright (C) 1994-2000 Algorithmics Ltd.
13 	0, 1204, 3062, 5746, 9193, 13348, 18162, 23592,
41 		/* sqrt(0) = 0 */  in ieee754dp_sqrt()
46 			/* sqrt(-Inf) = Nan */  in ieee754dp_sqrt()
58 			/* sqrt(-x) = Nan */  in ieee754dp_sqrt()
72 	scalx = 0;  in ieee754dp_sqrt()
73 	if (xe > 512) {		/* x > 2**-512? */  in ieee754dp_sqrt()
74 		xe -= 512;	/* x = x / 2**512 */  in ieee754dp_sqrt()
76 	} else if (xe < -512) { /* x < 2**-512? */  in ieee754dp_sqrt()
78 		scalx -= 256;  in ieee754dp_sqrt()
81 	x = builddp(0, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);  in ieee754dp_sqrt()
86 	yh = (yh >> 1) + 0x1ff80000;  in ieee754dp_sqrt()
87 	yh = yh - table[(yh >> 15) & 31];  in ieee754dp_sqrt()
88 	y.bits = ((u64) yh << 32) | (y.bits & 0xffffffff);  in ieee754dp_sqrt()
91 	/* t=x/y; y=y+t; py[n0]=py[n0]-0x00100006; py[n1]=0; */  in ieee754dp_sqrt()
94 	y.bits -= 0x0010000600000000LL;  in ieee754dp_sqrt()
95 	y.bits &= 0xffffffff00000000LL;  in ieee754dp_sqrt()
97 	/* triple to almost 56 sig. bits: y ~= sqrt(x) to within 1 ulp */  in ieee754dp_sqrt()
98 	/* t=y*y; z=t;	pt[n0]+=0x00100000; t+=z; z=(x-z)*y; */  in ieee754dp_sqrt()
101 	t.bexp += 0x001;  in ieee754dp_sqrt()
105 	/* t=z/(t+x) ;	pt[n0]+=0x00100000; y+=t; */  in ieee754dp_sqrt()
107 	t.bexp += 0x001;  in ieee754dp_sqrt()
122 			/* t = t-ulp */  in ieee754dp_sqrt()
123 			t.bits -= 1;  in ieee754dp_sqrt()
142 		scalx -= 1;  in ieee754dp_sqrt()