1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * IEEE754 floating point arithmetic
4*4882a593Smuzhiyun * double precision: MIN{,A}.f
5*4882a593Smuzhiyun * MIN : Scalar Floating-Point Minimum
6*4882a593Smuzhiyun * MINA: Scalar Floating-Point argument with Minimum Absolute Value
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * MIN.D : FPR[fd] = minNum(FPR[fs],FPR[ft])
9*4882a593Smuzhiyun * MINA.D: FPR[fd] = maxNumMag(FPR[fs],FPR[ft])
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun * MIPS floating point support
12*4882a593Smuzhiyun * Copyright (C) 2015 Imagination Technologies, Ltd.
13*4882a593Smuzhiyun * Author: Markos Chandras <markos.chandras@imgtec.com>
14*4882a593Smuzhiyun */
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include "ieee754dp.h"
17*4882a593Smuzhiyun
ieee754dp_fmax(union ieee754dp x,union ieee754dp y)18*4882a593Smuzhiyun union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y)
19*4882a593Smuzhiyun {
20*4882a593Smuzhiyun COMPXDP;
21*4882a593Smuzhiyun COMPYDP;
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun EXPLODEXDP;
24*4882a593Smuzhiyun EXPLODEYDP;
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun FLUSHXDP;
27*4882a593Smuzhiyun FLUSHYDP;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun ieee754_clearcx();
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun switch (CLPAIR(xc, yc)) {
32*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
33*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
34*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
35*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
36*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
37*4882a593Smuzhiyun return ieee754dp_nanxcpt(y);
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
40*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
41*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
42*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
43*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
44*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
45*4882a593Smuzhiyun return ieee754dp_nanxcpt(x);
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun /*
48*4882a593Smuzhiyun * Quiet NaN handling
49*4882a593Smuzhiyun */
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun /*
52*4882a593Smuzhiyun * The case of both inputs quiet NaNs
53*4882a593Smuzhiyun */
54*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
55*4882a593Smuzhiyun return x;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun /*
58*4882a593Smuzhiyun * The cases of exactly one input quiet NaN (numbers
59*4882a593Smuzhiyun * are here preferred as returned values to NaNs)
60*4882a593Smuzhiyun */
61*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
62*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
63*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
64*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
65*4882a593Smuzhiyun return x;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
68*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
69*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
70*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
71*4882a593Smuzhiyun return y;
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun /*
74*4882a593Smuzhiyun * Infinity and zero handling
75*4882a593Smuzhiyun */
76*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
77*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
78*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
79*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
80*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
81*4882a593Smuzhiyun return xs ? y : x;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
84*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
85*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
86*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
87*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
88*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
89*4882a593Smuzhiyun return ys ? x : y;
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
92*4882a593Smuzhiyun return ieee754dp_zero(xs & ys);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
95*4882a593Smuzhiyun DPDNORMX;
96*4882a593Smuzhiyun fallthrough;
97*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
98*4882a593Smuzhiyun DPDNORMY;
99*4882a593Smuzhiyun break;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
102*4882a593Smuzhiyun DPDNORMX;
103*4882a593Smuzhiyun }
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun /* Finally get to do some computation */
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun assert(xm & DP_HIDDEN_BIT);
108*4882a593Smuzhiyun assert(ym & DP_HIDDEN_BIT);
109*4882a593Smuzhiyun
110*4882a593Smuzhiyun /* Compare signs */
111*4882a593Smuzhiyun if (xs > ys)
112*4882a593Smuzhiyun return y;
113*4882a593Smuzhiyun else if (xs < ys)
114*4882a593Smuzhiyun return x;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun /* Signs of inputs are equal, let's compare exponents */
117*4882a593Smuzhiyun if (xs == 0) {
118*4882a593Smuzhiyun /* Inputs are both positive */
119*4882a593Smuzhiyun if (xe > ye)
120*4882a593Smuzhiyun return x;
121*4882a593Smuzhiyun else if (xe < ye)
122*4882a593Smuzhiyun return y;
123*4882a593Smuzhiyun } else {
124*4882a593Smuzhiyun /* Inputs are both negative */
125*4882a593Smuzhiyun if (xe > ye)
126*4882a593Smuzhiyun return y;
127*4882a593Smuzhiyun else if (xe < ye)
128*4882a593Smuzhiyun return x;
129*4882a593Smuzhiyun }
130*4882a593Smuzhiyun
131*4882a593Smuzhiyun /* Signs and exponents of inputs are equal, let's compare mantissas */
132*4882a593Smuzhiyun if (xs == 0) {
133*4882a593Smuzhiyun /* Inputs are both positive, with equal signs and exponents */
134*4882a593Smuzhiyun if (xm <= ym)
135*4882a593Smuzhiyun return y;
136*4882a593Smuzhiyun return x;
137*4882a593Smuzhiyun }
138*4882a593Smuzhiyun /* Inputs are both negative, with equal signs and exponents */
139*4882a593Smuzhiyun if (xm <= ym)
140*4882a593Smuzhiyun return x;
141*4882a593Smuzhiyun return y;
142*4882a593Smuzhiyun }
143*4882a593Smuzhiyun
ieee754dp_fmaxa(union ieee754dp x,union ieee754dp y)144*4882a593Smuzhiyun union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y)
145*4882a593Smuzhiyun {
146*4882a593Smuzhiyun COMPXDP;
147*4882a593Smuzhiyun COMPYDP;
148*4882a593Smuzhiyun
149*4882a593Smuzhiyun EXPLODEXDP;
150*4882a593Smuzhiyun EXPLODEYDP;
151*4882a593Smuzhiyun
152*4882a593Smuzhiyun FLUSHXDP;
153*4882a593Smuzhiyun FLUSHYDP;
154*4882a593Smuzhiyun
155*4882a593Smuzhiyun ieee754_clearcx();
156*4882a593Smuzhiyun
157*4882a593Smuzhiyun switch (CLPAIR(xc, yc)) {
158*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
159*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
160*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
161*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
162*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
163*4882a593Smuzhiyun return ieee754dp_nanxcpt(y);
164*4882a593Smuzhiyun
165*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
166*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
167*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
168*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
169*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
170*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
171*4882a593Smuzhiyun return ieee754dp_nanxcpt(x);
172*4882a593Smuzhiyun
173*4882a593Smuzhiyun /*
174*4882a593Smuzhiyun * Quiet NaN handling
175*4882a593Smuzhiyun */
176*4882a593Smuzhiyun
177*4882a593Smuzhiyun /*
178*4882a593Smuzhiyun * The case of both inputs quiet NaNs
179*4882a593Smuzhiyun */
180*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
181*4882a593Smuzhiyun return x;
182*4882a593Smuzhiyun
183*4882a593Smuzhiyun /*
184*4882a593Smuzhiyun * The cases of exactly one input quiet NaN (numbers
185*4882a593Smuzhiyun * are here preferred as returned values to NaNs)
186*4882a593Smuzhiyun */
187*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
188*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
189*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
190*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
191*4882a593Smuzhiyun return x;
192*4882a593Smuzhiyun
193*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
194*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
195*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
196*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
197*4882a593Smuzhiyun return y;
198*4882a593Smuzhiyun
199*4882a593Smuzhiyun /*
200*4882a593Smuzhiyun * Infinity and zero handling
201*4882a593Smuzhiyun */
202*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
203*4882a593Smuzhiyun return ieee754dp_inf(xs & ys);
204*4882a593Smuzhiyun
205*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
206*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
207*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
208*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
209*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
210*4882a593Smuzhiyun return x;
211*4882a593Smuzhiyun
212*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
213*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
214*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
215*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
216*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
217*4882a593Smuzhiyun return y;
218*4882a593Smuzhiyun
219*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
220*4882a593Smuzhiyun return ieee754dp_zero(xs & ys);
221*4882a593Smuzhiyun
222*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
223*4882a593Smuzhiyun DPDNORMX;
224*4882a593Smuzhiyun fallthrough;
225*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
226*4882a593Smuzhiyun DPDNORMY;
227*4882a593Smuzhiyun break;
228*4882a593Smuzhiyun
229*4882a593Smuzhiyun case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
230*4882a593Smuzhiyun DPDNORMX;
231*4882a593Smuzhiyun }
232*4882a593Smuzhiyun
233*4882a593Smuzhiyun /* Finally get to do some computation */
234*4882a593Smuzhiyun
235*4882a593Smuzhiyun assert(xm & DP_HIDDEN_BIT);
236*4882a593Smuzhiyun assert(ym & DP_HIDDEN_BIT);
237*4882a593Smuzhiyun
238*4882a593Smuzhiyun /* Compare exponent */
239*4882a593Smuzhiyun if (xe > ye)
240*4882a593Smuzhiyun return x;
241*4882a593Smuzhiyun else if (xe < ye)
242*4882a593Smuzhiyun return y;
243*4882a593Smuzhiyun
244*4882a593Smuzhiyun /* Compare mantissa */
245*4882a593Smuzhiyun if (xm < ym)
246*4882a593Smuzhiyun return y;
247*4882a593Smuzhiyun else if (xm > ym)
248*4882a593Smuzhiyun return x;
249*4882a593Smuzhiyun else if (xs == 0)
250*4882a593Smuzhiyun return x;
251*4882a593Smuzhiyun return y;
252*4882a593Smuzhiyun }
253