struct ieee754_csr oldcsr; 
struct _ieee754_csr oldcsr; 
ieee754dp ieee754dp_sqrt(ieee754dp x){	struct ieee754_csr oldcsr;	ieee754dp y, z, t;	unsigned scalx, yh;	COMPXDP;	EXPLODEXDP;	CLEARCX;	FLUSHXDP;	/* x == INF or NAN? */	switch (xc) {	case IEEE754_CLASS_QNAN:		/* sqrt(Nan) = Nan */		return ieee754dp_nanxcpt(x, "sqrt");	case IEEE754_CLASS_SNAN:		SETCX(IEEE754_INVALID_OPERATION);		return ieee754dp_nanxcpt(ieee754dp_indef(), "sqrt");	case IEEE754_CLASS_ZERO:		/* sqrt(0) = 0 */		return x;	case IEEE754_CLASS_INF:		if (xs) {			/* sqrt(-Inf) = Nan */			SETCX(IEEE754_INVALID_OPERATION);			return ieee754dp_nanxcpt(ieee754dp_indef(), "sqrt");		}		/* sqrt(+Inf) = Inf */		return x;	case IEEE754_CLASS_DNORM:		DPDNORMX;		/* fall through */	case IEEE754_CLASS_NORM:		if (xs) {			/* sqrt(-x) = Nan */			SETCX(IEEE754_INVALID_OPERATION);			return ieee754dp_nanxcpt(ieee754dp_indef(), "sqrt");		}		break;	}	/* save old csr; switch off INX enable & flag; set RN rounding */	oldcsr = ieee754_csr;	ieee754_csr.mx &= ~IEEE754_INEXACT;	ieee754_csr.sx &= ~IEEE754_INEXACT;	ieee754_csr.rm = IEEE754_RN;	/* adjust exponent to prevent overflow */	scalx = 0;	if (xe > 512) {		/* x > 2**-512? */		xe -= 512;	/* x = x / 2**512 */		scalx += 256;	} else if (xe < -512) {	/* x < 2**-512? */		xe += 512;	/* x = x * 2**512 */		scalx -= 256;	}	y = x = builddp(0, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);	/* magic initial approximation to almost 8 sig. bits */	yh = y.bits >> 32;	yh = (yh >> 1) + 0x1ff80000;	yh = yh - table[(yh >> 15) & 31];	y.bits = ((u64) yh << 32) | (y.bits & 0xffffffff);	/* Heron's rule once with correction to improve to ~18 sig. bits */	/* t=x/y; y=y+t; py[n0]=py[n0]-0x00100006; py[n1]=0; */	t = ieee754dp_div(x, y);	y = ieee754dp_add(y, t);	y.bits -= 0x0010000600000000LL;	y.bits &= 0xffffffff00000000LL;	/* triple to almost 56 sig. bits: y ~= sqrt(x) to within 1 ulp */	/* t=y*y; z=t;  pt[n0]+=0x00100000; t+=z; z=(x-z)*y; */	z = t = ieee754dp_mul(y, y);	t.parts.bexp += 0x001;	t = ieee754dp_add(t, z);	z = ieee754dp_mul(ieee754dp_sub(x, z), y);	/* t=z/(t+x) ;  pt[n0]+=0x00100000; y+=t; */	t = ieee754dp_div(z, ieee754dp_add(t, x));	t.parts.bexp += 0x001;	y = ieee754dp_add(y, t);	/* twiddle last bit to force y correctly rounded */	/* set RZ, clear INEX flag */	ieee754_csr.rm = IEEE754_RZ;	ieee754_csr.sx &= ~IEEE754_INEXACT;	/* t=x/y; ...chopped quotient, possibly inexact */	t = ieee754dp_div(x, y);	if (ieee754_csr.sx & IEEE754_INEXACT || t.bits != y.bits) {		if (!(ieee754_csr.sx & IEEE754_INEXACT))			/* t = t-ulp */			t.bits -= 1;		/* add inexact to result status */		oldcsr.cx |= IEEE754_INEXACT;		oldcsr.sx |= IEEE754_INEXACT;		switch (oldcsr.rm) {		case IEEE754_RP:			y.bits += 1;			/* drop through */		case IEEE754_RN:			t.bits += 1;			break;		}		/* y=y+t; ...chopped sum */		y = ieee754dp_add(y, t);		/* adjust scalx for correctly rounded sqrt(x) */		scalx -= 1;	}	/* py[n0]=py[n0]+scalx; ...scale back y */	y.parts.bexp += scalx;	/* restore rounding mode, possibly set inexact */	ieee754_csr = oldcsr;	return y;}
10457	/local/tlutelli/issta_data/temp/c/2005_temp/2005/10457/cd21dfcfbb5c43de54f6be795dde07397da2bc2f/dp_sqrt.c/buggy/arch/mips/math-emu/dp_sqrt.c