xref: /freebsd/sys/sys/qmath.h (revision 2f513db7)
1 /*-
2  * Copyright (c) 2018 Netflix, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 /*
30  * Data types and APIs for fixed-point math based on the "Q" number format.
31  *
32  * Author: Lawrence Stewart <lstewart@netflix.com>
33  *
34  * The 3 LSBs of all base data types are reserved for embedded control data:
35  *   bits 1-2 specify the radix point shift index i.e. 00,01,10,11 == 1,2,3,4
36  *   bit 3 specifies the radix point shift index multiplier as 2 (0) or 16 (1)
37  *
38  * This scheme can therefore represent Q numbers with [2,4,6,8,16,32,48,64] bits
39  * of precision after the binary radix point. The number of bits available for
40  * the integral component depends on the underlying storage type chosen.
41  */
42 
43 #ifndef	_SYS_QMATH_H_
44 #define	_SYS_QMATH_H_
45 
46 #include <machine/_stdint.h>
47 
48 typedef int8_t		s8q_t;
49 typedef uint8_t		u8q_t;
50 typedef int16_t		s16q_t;
51 typedef uint16_t	u16q_t;
52 typedef int32_t		s32q_t;
53 typedef uint32_t	u32q_t;
54 typedef int64_t		s64q_t;
55 typedef uint64_t	u64q_t;
56 /* typedef int128_t	s128q_t; Not yet */
57 /* typedef uint128_t	u128q_t; Not yet */
58 typedef	s64q_t		smaxq_t;
59 typedef	u64q_t		umaxq_t;
60 
61 #if defined(__GNUC__) && !defined(__clang__)
62 /* Ancient GCC hack to de-const, remove when GCC4 is removed. */
63 #define	Q_BT(q)		__typeof(1 * q)
64 #else
65 /* The underlying base type of 'q'. */
66 #define	Q_BT(q)		__typeof(q)
67 #endif
68 
69 /* Type-cast variable 'v' to the same underlying type as 'q'. */
70 #define	Q_TC(q, v)	((__typeof(q))(v))
71 
72 /* Number of total bits associated with the data type underlying 'q'. */
73 #define	Q_NTBITS(q)	((uint32_t)(sizeof(q) << 3))
74 
75 /* Number of LSBs reserved for control data. */
76 #define	Q_NCBITS	((uint32_t)3)
77 
78 /* Number of control-encoded bits reserved for fractional component data. */
79 #define	Q_NFCBITS(q) \
80     ((uint32_t)(((Q_GCRAW(q) & 0x3) + 1) << ((Q_GCRAW(q) & 0x4) ? 4 : 1)))
81 
82 /* Min/max number of bits that can be reserved for fractional component data. */
83 #define	Q_MINNFBITS(q)	((uint32_t)(2))
84 #define	Q_MAXNFBITS(q)	((uint32_t)(Q_NTBITS(q) - Q_SIGNED(q) - Q_NCBITS))
85 
86 /*
87  * Number of bits actually reserved for fractional component data. This can be
88  * less than the value returned by Q_NFCBITS() as we treat any excess
89  * control-encoded number of bits for the underlying data type as meaning all
90  * available bits are reserved for fractional component data i.e. zero int bits.
91  */
92 #define	Q_NFBITS(q) \
93     (Q_NFCBITS(q) > Q_MAXNFBITS(q) ? Q_MAXNFBITS(q) : Q_NFCBITS(q))
94 
95 /* Number of bits available for integer component data. */
96 #define	Q_NIBITS(q)	((uint32_t)(Q_NTBITS(q) - Q_RPSHFT(q) - Q_SIGNED(q)))
97 
98 /* The radix point offset relative to the LSB. */
99 #define	Q_RPSHFT(q)	(Q_NCBITS + Q_NFBITS(q))
100 
101 /* The sign bit offset relative to the LSB. */
102 #define	Q_SIGNSHFT(q)	(Q_NTBITS(q) - 1)
103 
104 /* Set the sign bit to 0 ('isneg' is F) or 1 ('isneg' is T). */
105 #define	Q_SSIGN(q, isneg) \
106     ((q) = ((Q_SIGNED(q) && (isneg)) ?	(q) | (1ULL << Q_SIGNSHFT(q)) : \
107 					(q) & ~(1ULL << Q_SIGNSHFT(q))))
108 
109 /* Manipulate the 'q' bits holding control/sign data. */
110 #define	Q_CRAWMASK(q)	0x7ULL
111 #define	Q_SRAWMASK(q)	(1ULL << Q_SIGNSHFT(q))
112 #define	Q_GCRAW(q)	((q) & Q_CRAWMASK(q))
113 #define	Q_GCVAL(q)	Q_GCRAW(q)
114 #define	Q_SCVAL(q, cv)	((q) = ((q) & ~Q_CRAWMASK(q)) | (cv))
115 
116 /* Manipulate the 'q' bits holding combined integer/fractional data. */
117 #define	Q_IFRAWMASK(q) \
118     Q_TC(q, Q_SIGNED(q) ? ~(Q_SRAWMASK(q) | Q_CRAWMASK(q)) : ~Q_CRAWMASK(q))
119 #define	Q_IFMAXVAL(q)	Q_TC(q, Q_IFRAWMASK(q) >> Q_NCBITS)
120 #define	Q_IFMINVAL(q)	Q_TC(q, Q_SIGNED(q) ? -Q_IFMAXVAL(q) : 0)
121 #define	Q_IFVALIMASK(q)	Q_TC(q, ~Q_IFVALFMASK(q))
122 #define	Q_IFVALFMASK(q)	Q_TC(q, (1ULL << Q_NFBITS(q)) - 1)
123 #define	Q_GIFRAW(q)	Q_TC(q, (q) & Q_IFRAWMASK(q))
124 #define	Q_GIFABSVAL(q)	Q_TC(q, Q_GIFRAW(q) >> Q_NCBITS)
125 #define	Q_GIFVAL(q)	Q_TC(q, Q_LTZ(q) ? -Q_GIFABSVAL(q) : Q_GIFABSVAL(q))
126 #define	Q_SIFVAL(q, ifv) \
127     ((q) = ((q) & (~(Q_SRAWMASK(q) | Q_IFRAWMASK(q)))) | \
128     (Q_TC(q, Q_ABS(ifv)) << Q_NCBITS) | \
129     (Q_LTZ(ifv) ? 1ULL << Q_SIGNSHFT(q) : 0))
130 #define	Q_SIFVALS(q, iv, fv) \
131     ((q) = ((q) & (~(Q_SRAWMASK(q) | Q_IFRAWMASK(q)))) | \
132     (Q_TC(q, Q_ABS(iv)) << Q_RPSHFT(q)) | \
133     (Q_TC(q, Q_ABS(fv)) << Q_NCBITS) | \
134     (Q_LTZ(iv) || Q_LTZ(fv) ? 1ULL << Q_SIGNSHFT(q) : 0))
135 
136 /* Manipulate the 'q' bits holding integer data. */
137 #define	Q_IRAWMASK(q)	Q_TC(q, Q_IFRAWMASK(q) & ~Q_FRAWMASK(q))
138 #define	Q_IMAXVAL(q)	Q_TC(q, Q_IRAWMASK(q) >> Q_RPSHFT(q))
139 #define	Q_IMINVAL(q)	Q_TC(q, Q_SIGNED(q) ? -Q_IMAXVAL(q) : 0)
140 #define	Q_GIRAW(q)	Q_TC(q, (q) & Q_IRAWMASK(q))
141 #define	Q_GIABSVAL(q)	Q_TC(q, Q_GIRAW(q) >> Q_RPSHFT(q))
142 #define	Q_GIVAL(q)	Q_TC(q, Q_LTZ(q) ? -Q_GIABSVAL(q) : Q_GIABSVAL(q))
143 #define	Q_SIVAL(q, iv) \
144     ((q) = ((q) & ~(Q_SRAWMASK(q) | Q_IRAWMASK(q))) | \
145     (Q_TC(q, Q_ABS(iv)) << Q_RPSHFT(q)) | \
146     (Q_LTZ(iv) ? 1ULL << Q_SIGNSHFT(q) : 0))
147 
148 /* Manipulate the 'q' bits holding fractional data. */
149 #define	Q_FRAWMASK(q)	Q_TC(q, ((1ULL << Q_NFBITS(q)) - 1) << Q_NCBITS)
150 #define	Q_FMAXVAL(q)	Q_TC(q, Q_FRAWMASK(q) >> Q_NCBITS)
151 #define	Q_GFRAW(q)	Q_TC(q, (q) & Q_FRAWMASK(q))
152 #define	Q_GFABSVAL(q)	Q_TC(q, Q_GFRAW(q) >> Q_NCBITS)
153 #define	Q_GFVAL(q)	Q_TC(q, Q_LTZ(q) ? -Q_GFABSVAL(q) : Q_GFABSVAL(q))
154 #define	Q_SFVAL(q, fv) \
155     ((q) = ((q) & ~(Q_SRAWMASK(q) | Q_FRAWMASK(q))) | \
156     (Q_TC(q, Q_ABS(fv)) << Q_NCBITS) | \
157     (Q_LTZ(fv) ? 1ULL << Q_SIGNSHFT(q) : 0))
158 
159 /*
160  * Calculate the number of bits required per 'base' digit, rounding up or down
161  * for non power-of-two bases.
162  */
163 #define	Q_BITSPERBASEDOWN(base) (flsll(base) - 1)
164 #define	Q_BITSPERBASEUP(base) (flsll(base) - (__builtin_popcountll(base) == 1))
165 #define	Q_BITSPERBASE(base, rnd) Q_BITSPERBASE##rnd(base)
166 
167 /*
168  * Upper bound number of digits required to render 'nbits' worth of integer
169  * component bits with numeric base 'base'. Overestimates for power-of-two
170  * bases.
171  */
172 #define	Q_NIBITS2NCHARS(nbits, base)					\
173 ({									\
174  	int _bitsperbase = Q_BITSPERBASE(base, DOWN);			\
175 	(((nbits) + _bitsperbase - 1) / _bitsperbase);			\
176 })
177 
178 #define	Q_NFBITS2NCHARS(nbits, base) (nbits)
179 
180 /*
181  * Maximum number of chars required to render 'q' as a C-string of base 'base'.
182  * Includes space for sign, radix point and NUL-terminator.
183  */
184 #define	Q_MAXSTRLEN(q, base) \
185     (2 + Q_NIBITS2NCHARS(Q_NIBITS(q), base) + \
186     Q_NFBITS2NCHARS(Q_NFBITS(q), base) + Q_SIGNED(q))
187 
188 /* Yield the next char from integer bits. */
189 #define	Q_IBITS2CH(q, bits, base)					\
190 ({									\
191     __typeof(bits) _tmp = (bits) / (base);				\
192     int _idx = (bits) - (_tmp * (base));				\
193     (bits) = _tmp;							\
194     "0123456789abcdef"[_idx];						\
195 })
196 
197 /* Yield the next char from fractional bits. */
198 #define	Q_FBITS2CH(q, bits, base)					\
199 ({									\
200     int _carry = 0, _idx, _nfbits = Q_NFBITS(q), _shift = 0;		\
201     /*									\
202      * Normalise enough MSBs to yield the next digit, multiply by the	\
203      * base, and truncate residual fractional bits post multiplication.	\
204      */									\
205     if (_nfbits > Q_BITSPERBASEUP(base)) {				\
206         /* Break multiplication into two steps to ensure no overflow. */\
207         _shift = _nfbits >> 1;						\
208         _carry = (((bits) & ((1ULL << _shift) - 1)) * (base)) >> _shift;\
209     }									\
210     _idx = ((((bits) >> _shift) * (base)) + _carry) >> (_nfbits - _shift);\
211     (bits) *= (base); /* With _idx computed, no overflow concern. */	\
212     (bits) &= (1ULL << _nfbits) - 1; /* Exclude residual int bits. */	\
213     "0123456789abcdef"[_idx];						\
214 })
215 
216 /*
217  * Render the C-string representation of 'q' into 's'. Returns a pointer to the
218  * final '\0' to allow for easy calculation of the rendered length and easy
219  * appending to the C-string.
220  */
221 #define	Q_TOSTR(q, prec, base, s, slen)					\
222 ({									\
223 	char *_r, *_s = s;						\
224 	int _i;								\
225 	if (Q_LTZ(q) && ((ptrdiff_t)(slen)) > 0)			\
226 		*_s++ = '-';						\
227 	Q_BT(q) _part = Q_GIABSVAL(q);					\
228 	_r = _s;							\
229 	do {								\
230 		/* Render integer chars in reverse order. */		\
231 		if ((_s - (s)) < ((ptrdiff_t)(slen)))			\
232 			*_s++ = Q_IBITS2CH(q, _part, base);		\
233 		else							\
234 			_r = NULL;					\
235 	} while (_part > 0 && _r != NULL);				\
236 	if (!((_s - (s)) < ((ptrdiff_t)(slen))))			\
237 		_r = NULL;						\
238 	_i = (_s - _r) >> 1; /* N digits requires int(N/2) swaps. */	\
239 	while (_i-- > 0 && _r != NULL) {				\
240 		/* Work from middle out to reverse integer chars. */	\
241 		*_s = *(_r + _i); /* Stash LHS char temporarily. */	\
242 		*(_r + _i) = *(_s - _i - 1); /* Copy RHS char to LHS. */\
243 		*(_s - _i - 1) = *_s; /* Copy LHS char to RHS. */	\
244 	}								\
245 	_i = (prec);							\
246 	if (_i != 0 && _r != NULL) {					\
247 		if ((_s - (s)) < ((ptrdiff_t)(slen)))			\
248 			*_s++ = '.';					\
249 		else							\
250 			_r = NULL;					\
251 		_part = Q_GFABSVAL(q);					\
252 		if (_i < 0 || _i > (int)Q_NFBITS(q))			\
253 			_i = Q_NFBITS(q);				\
254 		while (_i-- > 0 && _r != NULL) {			\
255 			/* Render fraction chars in correct order. */	\
256 			if ((_s - (s)) < ((ptrdiff_t)(slen)))		\
257 				*_s++ = Q_FBITS2CH(q, _part, base);	\
258 			else						\
259 				_r = NULL;				\
260 		}							\
261 	}								\
262 	if ((_s - (s)) < ((ptrdiff_t)(slen)) && _r != NULL)		\
263 		*_s = '\0';						\
264 	else {								\
265 		_r = NULL;						\
266 		if (((ptrdiff_t)(slen)) > 0)				\
267 			*(s) = '\0';					\
268 	}								\
269 	/* Return a pointer to the '\0' or NULL on overflow. */		\
270 	(_r != NULL ? _s : _r);						\
271 })
272 
273 /* Left shift an integral value to align with the int bits of 'q'. */
274 #define	Q_SHL(q, iv) \
275     (Q_LTZ(iv) ? -(int64_t)(Q_ABS(iv) << Q_NFBITS(q)) :	\
276     Q_TC(q, iv) << Q_NFBITS(q))
277 
278 /* Calculate the relative fractional precision between 'a' and 'b' in bits. */
279 #define	Q_RELPREC(a, b)	((int)Q_NFBITS(a) - (int)Q_NFBITS(b))
280 
281 /*
282  * Determine control bits for the desired 'rpshft' radix point shift. Rounds up
283  * to the nearest valid shift supported by the encoding scheme.
284  */
285 #define	Q_CTRLINI(rpshft) \
286     (((rpshft) <= 8) ? (((rpshft) - 1) >> 1) : (0x4 | (((rpshft) - 1) >> 4)))
287 
288 /*
289  * Convert decimal fractional value 'dfv' to its binary-encoded representation
290  * with 'nfbits' of binary precision. 'dfv' must be passed as a preprocessor
291  * literal to preserve leading zeroes. The returned result can be used to set a
292  * Q number's fractional bits e.g. using Q_SFVAL().
293  */
294 #define	Q_DFV2BFV(dfv, nfbits)				\
295 ({							\
296 	uint64_t _bfv = 0, _thresh = 5, _tmp = dfv;	\
297 	int _i = sizeof(""#dfv) - 1;			\
298 	/*						\
299 	 * Compute decimal threshold to determine which \
300 	 * conversion rounds will yield a binary 1.	\
301 	 */						\
302 	while (--_i > 0) {_thresh *= 10;}		\
303 	_i = (nfbits) - 1;				\
304 	while (_i >= 0) {				\
305 		if (_thresh <= _tmp) {			\
306 			_bfv |= 1ULL << _i;		\
307 			_tmp = _tmp - _thresh;		\
308 		}					\
309 		_i--; _tmp <<= 1;			\
310 	}						\
311 	_bfv;						\
312 })
313 
314 /*
315  * Initialise 'q' with raw integer value 'iv', decimal fractional value 'dfv',
316  * and radix point shift 'rpshft'. Must be done in two steps in case 'iv'
317  * depends on control bits being set e.g. when passing Q_INTMAX(q) as 'iv'.
318  */
319 #define	Q_INI(q, iv, dfv, rpshft) \
320 ({ \
321     (*(q)) = Q_CTRLINI(rpshft); \
322     Q_SIFVALS(*(q), iv, Q_DFV2BFV(dfv, Q_NFBITS(*(q)))); \
323 })
324 
325 /* Test if 'a' and 'b' fractional precision is the same (T) or not (F). */
326 #define	Q_PRECEQ(a, b)	(Q_NFBITS(a) == Q_NFBITS(b))
327 
328 /* Test if 'n' is a signed type (T) or not (F). Works with any numeric type. */
329 #define	Q_SIGNED(n)	(Q_TC(n, -1) < 0)
330 
331 /*
332  * Test if 'n' is negative. Works with any numeric type that uses the MSB as the
333  * sign bit, and also works with Q numbers.
334  */
335 #define	Q_LTZ(n)	(Q_SIGNED(n) && ((n) & Q_SRAWMASK(n)))
336 
337 /*
338  * Return absolute value of 'n'. Works with any standard numeric type that uses
339  * the MSB as the sign bit, and is signed/unsigned type safe.
340  * Does not work with Q numbers; use Q_QABS() instead.
341  */
342 #define	Q_ABS(n)	(Q_LTZ(n) ? -(n) : (n))
343 
344 /*
345  * Return an absolute value interpretation of 'q'.
346  */
347 #define	Q_QABS(q)	(Q_SIGNED(q) ? (q) & ~Q_SRAWMASK(q) : (q))
348 
349 /* Convert 'q' to float or double representation. */
350 #define	Q_Q2F(q)	((float)Q_GIFVAL(q) / (float)(1ULL << Q_NFBITS(q)))
351 #define	Q_Q2D(q)	((double)Q_GIFVAL(q) / (double)(1ULL << Q_NFBITS(q)))
352 
353 /* Numerically compare 'a' and 'b' as whole numbers using provided operators. */
354 #define	Q_QCMPQ(a, b, intcmp, fraccmp) \
355     ((Q_GIVAL(a) intcmp Q_GIVAL(b)) || \
356     ((Q_GIVAL(a) == Q_GIVAL(b)) && (Q_GFVAL(a) fraccmp Q_GFVAL(b))))
357 
358 /* Test if 'a' is numerically less than 'b' (T) or not (F). */
359 #define	Q_QLTQ(a, b)	Q_QCMPQ(a, b, <, <)
360 
361 /* Test if 'a' is numerically less than or equal to 'b' (T) or not (F). */
362 #define	Q_QLEQ(a, b)	Q_QCMPQ(a, b, <, <=)
363 
364 /* Test if 'a' is numerically greater than 'b' (T) or not (F). */
365 #define	Q_QGTQ(a, b)	Q_QCMPQ(a, b, >, >)
366 
367 /* Test if 'a' is numerically greater than or equal to 'b' (T) or not (F). */
368 #define	Q_QGEQ(a, b)	Q_QCMPQ(a, b, >, >=)
369 
370 /* Test if 'a' is numerically equal to 'b' (T) or not (F). */
371 #define	Q_QEQ(a, b)	Q_QCMPQ(a, b, ==, ==)
372 
373 /* Test if 'a' is numerically not equal to 'b' (T) or not (F). */
374 #define	Q_QNEQ(a, b)	Q_QCMPQ(a, b, !=, !=)
375 
376 /* Returns the numerically larger of 'a' and 'b'. */
377 #define	Q_QMAXQ(a, b)	(Q_GT(a, b) ? (a) : (b))
378 
379 /* Returns the numerically smaller of 'a' and 'b'. */
380 #define	Q_QMINQ(a, b)	(Q_LT(a, b) ? (a) : (b))
381 
382 /*
383  * Test if 'a' can be represented by 'b' with full accuracy (T) or not (F).
384  * The type casting has to be done to a's type so that any truncation caused by
385  * the casts will not affect the logic.
386  */
387 #define	Q_QCANREPQ(a, b) \
388     ((((Q_LTZ(a) && Q_SIGNED(b)) || !Q_LTZ(a)) && \
389     Q_GIABSVAL(a) <= Q_TC(a, Q_IMAXVAL(b)) && \
390     Q_GFABSVAL(a) <= Q_TC(a, Q_FMAXVAL(b))) ? \
391     0 : EOVERFLOW)
392 
393 /* Test if raw integer value 'i' can be represented by 'q' (T) or not (F). */
394 #define	Q_QCANREPI(q, i) \
395     ((((Q_LTZ(i) && Q_SIGNED(q)) || !Q_LTZ(i)) && \
396     Q_ABS(i) <= Q_TC(i, Q_IMAXVAL(q))) ? 0 : EOVERFLOW)
397 
398 /*
399  * Returns a Q variable debug format string with appropriate modifiers and
400  * padding relevant to the underlying Q data type.
401  */
402 #define	Q_DEBUGFMT_(prefmt, postfmt, mod, hexpad)			\
403     prefmt								\
404     /* Var name + address. */						\
405     "\"%s\"@%p"								\
406     /* Data type. */							\
407     "\n\ttype=%c%dq_t, "						\
408     /* Qm.n notation; 'm' = # int bits, 'n' = # frac bits. */		\
409     "Qm.n=Q%d.%d, "							\
410     /* Radix point shift relative to the underlying data type's LSB. */	\
411     "rpshft=%d, "							\
412     /* Min/max integer values which can be represented. */		\
413     "imin=0x%0" #mod "x, "						\
414     "imax=0x%0" #mod "x"						\
415     /* Raw hex dump of all bits. */					\
416     "\n\tqraw=0x%0" #hexpad #mod "x"					\
417     /* Bit masks for int/frac/ctrl bits. */				\
418     "\n\timask=0x%0" #hexpad #mod "x, "					\
419     "fmask=0x%0" #hexpad #mod "x, "					\
420     "cmask=0x%0" #hexpad #mod "x, "					\
421     "ifmask=0x%0" #hexpad #mod "x"					\
422     /* Hex dump of masked int bits; 'iraw' includes shift */		\
423     "\n\tiraw=0x%0" #hexpad #mod "x, "					\
424     "iabsval=0x%" #mod "x, "						\
425     "ival=0x%" #mod "x"					\
426     /* Hex dump of masked frac bits; 'fraw' includes shift */		\
427     "\n\tfraw=0x%0" #hexpad #mod "x, "					\
428     "fabsval=0x%" #mod "x, "						\
429     "fval=0x%" #mod "x"							\
430     "%s"								\
431     postfmt
432 
433 #define	Q_DEBUGFMT(q, prefmt, postfmt)					\
434       sizeof(q) == 8 ? Q_DEBUGFMT_(prefmt, postfmt, j, 16)	:	\
435       sizeof(q) == 4 ? Q_DEBUGFMT_(prefmt, postfmt,  , 8)	:	\
436       sizeof(q) == 2 ? Q_DEBUGFMT_(prefmt, postfmt, h, 4)	:	\
437       sizeof(q) == 1 ? Q_DEBUGFMT_(prefmt, postfmt, hh, 2)	:	\
438       prefmt "\"%s\"@%p: invalid" postfmt				\
439 
440 /*
441  * Returns a format string and data suitable for printf-like rendering
442  * e.g. Print to console with a trailing newline: printf(Q_DEBUG(q, "", "\n"));
443  */
444 #define	Q_DEBUG(q, prefmt, postfmt, incfmt)				\
445       Q_DEBUGFMT(q, prefmt, postfmt)					\
446     , #q								\
447     , &(q)								\
448     , Q_SIGNED(q) ? 's' : 'u'						\
449     , Q_NTBITS(q)							\
450     , Q_NIBITS(q)							\
451     , Q_NFBITS(q)							\
452     , Q_RPSHFT(q)							\
453     , Q_IMINVAL(q)							\
454     , Q_IMAXVAL(q)							\
455     , (q)								\
456     , Q_IRAWMASK(q)							\
457     , Q_FRAWMASK(q)							\
458     , Q_TC(q, Q_CRAWMASK(q))						\
459     , Q_IFRAWMASK(q)							\
460     , Q_GIRAW(q)							\
461     , Q_GIABSVAL(q)							\
462     , Q_GIVAL(q)							\
463     , Q_GFRAW(q)							\
464     , Q_GFABSVAL(q)							\
465     , Q_GFVAL(q)							\
466     , (incfmt) ? Q_DEBUGFMT(q, "\nfmt:", "") : ""			\
467 
468 /*
469  * If precision differs, attempt to normalise to the greater precision that
470  * preserves the integer component of both 'a' and 'b'.
471  */
472 #define	Q_NORMPREC(a, b)						\
473 ({									\
474 	int _perr = 0, _relprec = Q_RELPREC(*(a), b);			\
475 	if (_relprec != 0)						\
476 		_perr = ERANGE; /* XXXLAS: Do precision normalisation! */\
477 	_perr;								\
478 })
479 
480 /* Clone r's control bits and int/frac value into 'l'. */
481 #define	Q_QCLONEQ(l, r)							\
482 ({									\
483 	Q_BT(*(l)) _l = Q_GCVAL(r);					\
484 	int _err = Q_QCANREPQ(r, _l);					\
485 	if (!_err) {							\
486 		*(l) = _l;						\
487 		Q_SIFVAL(*(l), Q_GIFVAL(r));				\
488 	}								\
489 	_err;								\
490 })
491 
492 /* Copy r's int/frac vals into 'l', retaining 'l's precision and signedness. */
493 #define	Q_QCPYVALQ(l, r)						\
494 ({									\
495 	int _err = Q_QCANREPQ(r, *(l));					\
496 	if (!_err)							\
497 		Q_SIFVALS(*(l), Q_GIVAL(r), Q_GFVAL(r));		\
498 	_err;								\
499 })
500 
501 #define	Q_QADDSUBQ(a, b, eop)						\
502 ({									\
503 	int _aserr;							\
504 	if ((_aserr = Q_NORMPREC(a, b))) while(0); /* NOP */		\
505 	else if ((eop) == '+') {					\
506 		if (Q_IFMAXVAL(*(a)) - Q_GIFABSVAL(b) < Q_GIFVAL(*(a)))	\
507 			_aserr = EOVERFLOW; /* [+/-a + +b] > max(a) */	\
508 		else							\
509 			Q_SIFVAL(*(a), Q_GIFVAL(*(a)) + Q_TC(*(a),	\
510 			    Q_GIFABSVAL(b)));				\
511 	} else { /* eop == '-' */					\
512 		if (Q_IFMINVAL(*(a)) + Q_GIFABSVAL(b) > Q_GIFVAL(*(a)))	\
513 			_aserr = EOVERFLOW; /* [+/-a - +b] < min(a) */	\
514 		else							\
515 			Q_SIFVAL(*(a), Q_GIFVAL(*(a)) - Q_TC(*(a),	\
516 			    Q_GIFABSVAL(b)));				\
517 	}								\
518 	_aserr;								\
519 })
520 #define	Q_QADDQ(a, b) Q_QADDSUBQ(a, b, (Q_LTZ(b) ? '-' : '+'))
521 #define	Q_QSUBQ(a, b) Q_QADDSUBQ(a, b, (Q_LTZ(b) ? '+' : '-'))
522 
523 #define	Q_QDIVQ(a, b)							\
524 ({									\
525 	int _err;							\
526 	if ((_err = Q_NORMPREC(a, b))) while(0); /* NOP */		\
527 	else if (Q_GIFABSVAL(b) == 0 || (!Q_SIGNED(*(a)) && Q_LTZ(b)))	\
528 		_err = EINVAL; /* Divide by zero or cannot represent. */\
529 	/* XXXLAS: Handle overflow. */					\
530 	else if (Q_GIFABSVAL(*(a)) != 0) { /* Result expected. */	\
531 		Q_SIFVAL(*(a),						\
532 		    ((Q_GIVAL(*(a)) << Q_NFBITS(*(a))) / Q_GIFVAL(b)) +	\
533 		    (Q_GFVAL(b) == 0 ? 0 :				\
534 		    ((Q_GFVAL(*(a)) << Q_NFBITS(*(a))) / Q_GFVAL(b))));	\
535 	}								\
536 	_err;								\
537 })
538 
539 #define	Q_QMULQ(a, b)							\
540 ({									\
541 	int _mulerr;							\
542 	if ((_mulerr = Q_NORMPREC(a, b))) while(0); /* NOP */		\
543 	else if (!Q_SIGNED(*(a)) && Q_LTZ(b))				\
544 		_mulerr = EINVAL;					\
545 	else if (Q_GIFABSVAL(b) != 0 &&					\
546 	    Q_IFMAXVAL(*(a)) / Q_GIFABSVAL(b) < Q_GIFABSVAL(*(a)))	\
547 		_mulerr = EOVERFLOW;					\
548 	else								\
549 		Q_SIFVAL(*(a), (Q_GIFVAL(*(a)) * Q_GIFVAL(b)) >>	\
550 		    Q_NFBITS(*(a)));					\
551 	_mulerr;							\
552 })
553 
554 #define	Q_QCPYVALI(q, i)						\
555 ({									\
556 	int _err = Q_QCANREPI(*(q), i);					\
557 	if (!_err)							\
558 		Q_SIFVAL(*(q), Q_SHL(*(q), i));				\
559 	_err;								\
560 })
561 
562 #define	Q_QADDSUBI(q, i, eop)						\
563 ({									\
564 	int _aserr = 0;							\
565 	if (Q_NTBITS(*(q)) < (uint32_t)flsll(Q_ABS(i)))			\
566 		_aserr = EOVERFLOW; /* i cannot fit in q's type. */	\
567 	else if ((eop) == '+') {					\
568 		if (Q_IMAXVAL(*(q)) - Q_TC(*(q), Q_ABS(i)) <		\
569 		    Q_GIVAL(*(q)))					\
570 			_aserr = EOVERFLOW; /* [+/-q + +i] > max(q) */	\
571 		else							\
572 			Q_SIFVAL(*(q), Q_GIFVAL(*(q)) +			\
573 			    Q_SHL(*(q), Q_ABS(i)));			\
574 	} else { /* eop == '-' */					\
575 		if (Q_IMINVAL(*(q)) + Q_ABS(i) > Q_GIVAL(*(q)))		\
576 			_aserr = EOVERFLOW; /* [+/-q - +i] < min(q) */	\
577 		else							\
578 			Q_SIFVAL(*(q), Q_GIFVAL(*(q)) -			\
579 			    Q_SHL(*(q), Q_ABS(i)));			\
580 	}								\
581 	_aserr;								\
582 })
583 #define	Q_QADDI(q, i) Q_QADDSUBI(q, i, (Q_LTZ(i) ? '-' : '+'))
584 #define	Q_QSUBI(q, i) Q_QADDSUBI(q, i, (Q_LTZ(i) ? '+' : '-'))
585 
586 #define	Q_QDIVI(q, i)							\
587 ({									\
588 	int _diverr = 0;						\
589 	if ((i) == 0 || (!Q_SIGNED(*(q)) && Q_LTZ(i)))			\
590 		_diverr = EINVAL; /* Divide by zero or cannot represent. */\
591 	else if (Q_GIFABSVAL(*(q)) != 0) { /* Result expected. */	\
592 		Q_SIFVAL(*(q), Q_GIFVAL(*(q)) / Q_TC(*(q), i));		\
593 		if (Q_GIFABSVAL(*(q)) == 0)				\
594 			_diverr = ERANGE; /* q underflow. */		\
595 	}								\
596 	_diverr;							\
597 })
598 
599 #define	Q_QMULI(q, i)							\
600 ({									\
601 	int _mulerr = 0;						\
602 	if (!Q_SIGNED(*(q)) && Q_LTZ(i))				\
603 		_mulerr = EINVAL; /* Cannot represent. */		\
604 	else if ((i) != 0 && Q_IFMAXVAL(*(q)) / Q_TC(*(q), Q_ABS(i)) <	\
605 	    Q_GIFABSVAL(*(q)))						\
606 		_mulerr = EOVERFLOW;					\
607 	else								\
608 		Q_SIFVAL(*(q), Q_GIFVAL(*(q)) * Q_TC(*(q), i));		\
609 	_mulerr;							\
610 })
611 
612 #define	Q_QFRACI(q, in, id)						\
613 ({									\
614 	uint64_t _tmp;							\
615 	int _err = 0;							\
616 	if ((id) == 0)							\
617 		_err = EINVAL; /* Divide by zero. */			\
618 	else if ((in) == 0)						\
619 		Q_SIFVAL(*(q), in);					\
620 	else if ((_tmp = Q_ABS(in)) > (UINT64_MAX >> Q_RPSHFT(*(q))))	\
621 		_err = EOVERFLOW; /* _tmp overflow. */			\
622 	else {								\
623 		_tmp = Q_SHL(*(q), _tmp) / Q_ABS(id);			\
624 		if (Q_QCANREPI(*(q), _tmp & Q_IFVALIMASK(*(q))))	\
625 			_err = EOVERFLOW; /* q overflow. */		\
626 		else {							\
627 			Q_SIFVAL(*(q), _tmp);				\
628 			Q_SSIGN(*(q), (Q_LTZ(in) && !Q_LTZ(id)) ||	\
629 			    (!Q_LTZ(in) && Q_LTZ(id)));			\
630 			if (_tmp == 0)					\
631 				_err = ERANGE; /* q underflow. */	\
632 		}							\
633 	}								\
634 	_err;								\
635 })
636 
637 #endif	/* _SYS_QMATH_H_ */
638