3 /*-
4  * SPDX-License-Identifier: BSD-3-Clause
10  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
69  * 2 bits (a la fpu_shr(), but we do not bother with fp->fp_sticky).
72  * Note that we may leave the value 2.0 in fp->fp_mant; it is the caller's
82 	m0 = fp->fp_mant[0];  in round()
83 	m1 = fp->fp_mant[1];  in round()
84 	m2 = fp->fp_mant[2];  in round()
85 	m3 = fp->fp_mant[3];  in round()
87 	s = fp->fp_sticky;  in round()
90 	m3 = (m3 >> FP_NG) | (m2 << (32 - FP_NG));  in round()
91 	m2 = (m2 >> FP_NG) | (m1 << (32 - FP_NG));  in round()
92 	m1 = (m1 >> FP_NG) | (m0 << (32 - FP_NG));  in round()
98 	fe->fe_cx |= FPSCR_XX|FPSCR_FI;	/* inexact */  in round()
101 	switch ((fe->fe_fpscr) & FPSCR_RN) {  in round()
106 		 * but round & sticky both clear, then we want to round  in round()
111 		if ((gr & 1) || fp->fp_sticky || (m3 & 1))  in round()
120 		/* Round towards -Inf: up if negative, down if positive. */  in round()
121 		if (fp->fp_sign)  in round()
127 		if (!fp->fp_sign)  in round()
133 	fe->fe_cx |= FPSCR_FR;  in round()
139 	fp->fp_mant[0] = m0;  in round()
140 	fp->fp_mant[1] = m1;  in round()
141 	fp->fp_mant[2] = m2;  in round()
142 	fp->fp_mant[3] = m3;  in round()
146 	fp->fp_mant[0] = m0;  in round()
147 	fp->fp_mant[1] = m1;  in round()
148 	fp->fp_mant[2] = m2;  in round()
149 	fp->fp_mant[3] = m3;  in round()
154  * For overflow: return true if overflow is to go to +/-Inf, according
164 	switch ((fe->fe_fpscr) & FPSCR_RN) {  in toinf()
178 	case FP_RM:		/* toward -Inf iff negative */  in toinf()
183 		fe->fe_cx |= FPSCR_OX;  in toinf()
188  * fpn -> int (int value returned as return value).
199 	sign = fp->fp_sign;  in fpu_ftoi()
200 	switch (fp->fp_class) {  in fpu_ftoi()
208 		 * shifting any guard and round bits out into the sticky  in fpu_ftoi()
210 		 * inexact exception if sticky is set (see round()).  in fpu_ftoi()
215 		if ((exp = fp->fp_exp) >= 32)  in fpu_ftoi()
218 		if (fpu_shr(fp, FP_NMANT - 1 - exp) != 0)  in fpu_ftoi()
219 			fe->fe_cx |= FPSCR_UX;  in fpu_ftoi()
220 		i = fp->fp_mant[3];  in fpu_ftoi()
223 		return (sign ? -i : i);  in fpu_ftoi()
229 	fe->fe_cx |= FPSCR_VXCVI;  in fpu_ftoi()
234  * fpn -> extended int (high bits of int value returned as return value).
245 	sign = fp->fp_sign;  in fpu_ftox()
246 	switch (fp->fp_class) {  in fpu_ftox()
255 		 * shifting any guard and round bits out into the sticky  in fpu_ftox()
257 		 * inexact exception if sticky is set (see round()).  in fpu_ftox()
262 		if ((exp = fp->fp_exp) >= 64)  in fpu_ftox()
265 		if (fpu_shr(fp, FP_NMANT - 1 - exp) != 0)  in fpu_ftox()
266 			fe->fe_cx |= FPSCR_UX;  in fpu_ftox()
267 		i = ((u_int64_t)fp->fp_mant[2]<<32)|fp->fp_mant[3];  in fpu_ftox()
270 		return (sign ? -i : i);  in fpu_ftox()
276 	fe->fe_cx |= FPSCR_VXCVI;  in fpu_ftox()
281  * fpn -> single (32 bit single returned as return value).
282  * We assume <= 29 bits in a single-precision fraction (1.f part).
287 	u_int sign = fp->fp_sign << 31;  in fpu_ftos()
291 #define	SNG_MASK	(SNG_EXP(1) - 1)	/* mask for fraction */  in fpu_ftos()
293 	/* Take care of non-numbers first. */  in fpu_ftos()
297 		 * Note that fp->fp_mant[0] has the quiet bit set,  in fpu_ftos()
300 		(void) fpu_shr(fp, FP_NMANT - 1 - SNG_FRACBITS);  in fpu_ftos()
312 	 * single-precision range.  If the number is subnormal, move  in fpu_ftos()
330 	if ((exp = fp->fp_exp + SNG_EXP_BIAS) <= 0) {	/* subnormal */  in fpu_ftos()
331 		/* -NG for g,r; -SNG_FRACBITS-exp for fraction */  in fpu_ftos()
332 		(void) fpu_shr(fp, FP_NMANT - FP_NG - SNG_FRACBITS - exp);  in fpu_ftos()
333 		if (round(fe, fp) && fp->fp_mant[3] == SNG_EXP(1))  in fpu_ftos()
335 		if ((fe->fe_cx & FPSCR_FI) ||  in fpu_ftos()
336 		    (fe->fe_fpscr & FPSCR_UX))  in fpu_ftos()
337 			fe->fe_cx |= FPSCR_UX;  in fpu_ftos()
338 		return (sign | SNG_EXP(0) | fp->fp_mant[3]);  in fpu_ftos()
340 	/* -FP_NG for g,r; -1 for implied 1; -SNG_FRACBITS for fraction */  in fpu_ftos()
341 	(void) fpu_shr(fp, FP_NMANT - FP_NG - 1 - SNG_FRACBITS);  in fpu_ftos()
343 	if ((fp->fp_mant[3] & SNG_EXP(1 << FP_NG)) == 0)  in fpu_ftos()
346 	if (round(fe, fp) && fp->fp_mant[3] == SNG_EXP(2))  in fpu_ftos()
352 		return (sign | SNG_EXP(SNG_EXP_INFNAN - 1) | SNG_MASK);  in fpu_ftos()
356 	return (sign | SNG_EXP(exp) | (fp->fp_mant[3] & SNG_MASK));  in fpu_ftos()
360  * fpn -> double (32 bit high-order result returned; 32-bit low order result
368 	u_int sign = fp->fp_sign << 31;  in fpu_ftod()
372 #define	DBL_MASK	(DBL_EXP(1) - 1)  in fpu_ftod()
375 		(void) fpu_shr(fp, FP_NMANT - 1 - DBL_FRACBITS);  in fpu_ftod()
388 	if ((exp = fp->fp_exp + DBL_EXP_BIAS) <= 0) {  in fpu_ftod()
389 		(void) fpu_shr(fp, FP_NMANT - FP_NG - DBL_FRACBITS - exp);  in fpu_ftod()
390 		if (round(fe, fp) && fp->fp_mant[2] == DBL_EXP(1)) {  in fpu_ftod()
394 		if ((fe->fe_cx & FPSCR_FI) ||  in fpu_ftod()
395 		    (fe->fe_fpscr & FPSCR_UX))  in fpu_ftod()
396 			fe->fe_cx |= FPSCR_UX;  in fpu_ftod()
400 	(void) fpu_shr(fp, FP_NMANT - FP_NG - 1 - DBL_FRACBITS);  in fpu_ftod()
401 	if (round(fe, fp) && fp->fp_mant[2] == DBL_EXP(2))  in fpu_ftod()
404 		fe->fe_cx |= FPSCR_OX | FPSCR_UX;  in fpu_ftod()
413 	res[1] = fp->fp_mant[3];  in fpu_ftod()
414 	return (sign | DBL_EXP(exp) | (fp->fp_mant[2] & DBL_MASK));  in fpu_ftod()