Merge tag 'sound-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...
[linux-2.6-microblaze.git] / arch / parisc / math-emu / sfrem.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Linux/PA-RISC Project (http://www.parisc-linux.org/)
4  *
5  * Floating-point emulation code
6  *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
7  */
8 /*
9  * BEGIN_DESC
10  *
11  *  File:
12  *      @(#)    pa/spmath/sfrem.c               $Revision: 1.1 $
13  *
14  *  Purpose:
15  *      Single Precision Floating-point Remainder
16  *
17  *  External Interfaces:
18  *      sgl_frem(srcptr1,srcptr2,dstptr,status)
19  *
20  *  Internal Interfaces:
21  *
22  *  Theory:
23  *      <<please update with a overview of the operation of this file>>
24  *
25  * END_DESC
26 */
27
28
29
30 #include "float.h"
31 #include "sgl_float.h"
32
33 /*
34  *  Single Precision Floating-point Remainder
35  */
36
37 int
38 sgl_frem (sgl_floating_point * srcptr1, sgl_floating_point * srcptr2,
39           sgl_floating_point * dstptr, unsigned int *status)
40 {
41         register unsigned int opnd1, opnd2, result;
42         register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount;
43         register boolean roundup = FALSE;
44
45         opnd1 = *srcptr1;
46         opnd2 = *srcptr2;
47         /*
48          * check first operand for NaN's or infinity
49          */
50         if ((opnd1_exponent = Sgl_exponent(opnd1)) == SGL_INFINITY_EXPONENT) {
51                 if (Sgl_iszero_mantissa(opnd1)) {
52                         if (Sgl_isnotnan(opnd2)) {
53                                 /* invalid since first operand is infinity */
54                                 if (Is_invalidtrap_enabled()) 
55                                         return(INVALIDEXCEPTION);
56                                 Set_invalidflag();
57                                 Sgl_makequietnan(result);
58                                 *dstptr = result;
59                                 return(NOEXCEPTION);
60                         }
61                 }
62                 else {
63                         /*
64                          * is NaN; signaling or quiet?
65                          */
66                         if (Sgl_isone_signaling(opnd1)) {
67                                 /* trap if INVALIDTRAP enabled */
68                                 if (Is_invalidtrap_enabled()) 
69                                         return(INVALIDEXCEPTION);
70                                 /* make NaN quiet */
71                                 Set_invalidflag();
72                                 Sgl_set_quiet(opnd1);
73                         }
74                         /* 
75                          * is second operand a signaling NaN? 
76                          */
77                         else if (Sgl_is_signalingnan(opnd2)) {
78                                 /* trap if INVALIDTRAP enabled */
79                                 if (Is_invalidtrap_enabled()) 
80                                         return(INVALIDEXCEPTION);
81                                 /* make NaN quiet */
82                                 Set_invalidflag();
83                                 Sgl_set_quiet(opnd2);
84                                 *dstptr = opnd2;
85                                 return(NOEXCEPTION);
86                         }
87                         /*
88                          * return quiet NaN
89                          */
90                         *dstptr = opnd1;
91                         return(NOEXCEPTION);
92                 }
93         } 
94         /*
95          * check second operand for NaN's or infinity
96          */
97         if ((opnd2_exponent = Sgl_exponent(opnd2)) == SGL_INFINITY_EXPONENT) {
98                 if (Sgl_iszero_mantissa(opnd2)) {
99                         /*
100                          * return first operand
101                          */
102                         *dstptr = opnd1;
103                         return(NOEXCEPTION);
104                 }
105                 /*
106                  * is NaN; signaling or quiet?
107                  */
108                 if (Sgl_isone_signaling(opnd2)) {
109                         /* trap if INVALIDTRAP enabled */
110                         if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
111                         /* make NaN quiet */
112                         Set_invalidflag();
113                         Sgl_set_quiet(opnd2);
114                 }
115                 /*
116                  * return quiet NaN
117                  */
118                 *dstptr = opnd2;
119                 return(NOEXCEPTION);
120         }
121         /*
122          * check second operand for zero
123          */
124         if (Sgl_iszero_exponentmantissa(opnd2)) {
125                 /* invalid since second operand is zero */
126                 if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
127                 Set_invalidflag();
128                 Sgl_makequietnan(result);
129                 *dstptr = result;
130                 return(NOEXCEPTION);
131         }
132
133         /* 
134          * get sign of result
135          */
136         result = opnd1;  
137
138         /* 
139          * check for denormalized operands
140          */
141         if (opnd1_exponent == 0) {
142                 /* check for zero */
143                 if (Sgl_iszero_mantissa(opnd1)) {
144                         *dstptr = opnd1;
145                         return(NOEXCEPTION);
146                 }
147                 /* normalize, then continue */
148                 opnd1_exponent = 1;
149                 Sgl_normalize(opnd1,opnd1_exponent);
150         }
151         else {
152                 Sgl_clear_signexponent_set_hidden(opnd1);
153         }
154         if (opnd2_exponent == 0) {
155                 /* normalize, then continue */
156                 opnd2_exponent = 1;
157                 Sgl_normalize(opnd2,opnd2_exponent);
158         }
159         else {
160                 Sgl_clear_signexponent_set_hidden(opnd2);
161         }
162
163         /* find result exponent and divide step loop count */
164         dest_exponent = opnd2_exponent - 1;
165         stepcount = opnd1_exponent - opnd2_exponent;
166
167         /*
168          * check for opnd1/opnd2 < 1
169          */
170         if (stepcount < 0) {
171                 /*
172                  * check for opnd1/opnd2 > 1/2
173                  *
174                  * In this case n will round to 1, so 
175                  *    r = opnd1 - opnd2 
176                  */
177                 if (stepcount == -1 && Sgl_isgreaterthan(opnd1,opnd2)) {
178                         Sgl_all(result) = ~Sgl_all(result);   /* set sign */
179                         /* align opnd2 with opnd1 */
180                         Sgl_leftshiftby1(opnd2); 
181                         Sgl_subtract(opnd2,opnd1,opnd2);
182                         /* now normalize */
183                         while (Sgl_iszero_hidden(opnd2)) {
184                                 Sgl_leftshiftby1(opnd2);
185                                 dest_exponent--;
186                         }
187                         Sgl_set_exponentmantissa(result,opnd2);
188                         goto testforunderflow;
189                 }
190                 /*
191                  * opnd1/opnd2 <= 1/2
192                  *
193                  * In this case n will round to zero, so 
194                  *    r = opnd1
195                  */
196                 Sgl_set_exponentmantissa(result,opnd1);
197                 dest_exponent = opnd1_exponent;
198                 goto testforunderflow;
199         }
200
201         /*
202          * Generate result
203          *
204          * Do iterative subtract until remainder is less than operand 2.
205          */
206         while (stepcount-- > 0 && Sgl_all(opnd1)) {
207                 if (Sgl_isnotlessthan(opnd1,opnd2))
208                         Sgl_subtract(opnd1,opnd2,opnd1);
209                 Sgl_leftshiftby1(opnd1);
210         }
211         /*
212          * Do last subtract, then determine which way to round if remainder 
213          * is exactly 1/2 of opnd2 
214          */
215         if (Sgl_isnotlessthan(opnd1,opnd2)) {
216                 Sgl_subtract(opnd1,opnd2,opnd1);
217                 roundup = TRUE;
218         }
219         if (stepcount > 0 || Sgl_iszero(opnd1)) {
220                 /* division is exact, remainder is zero */
221                 Sgl_setzero_exponentmantissa(result);
222                 *dstptr = result;
223                 return(NOEXCEPTION);
224         }
225
226         /* 
227          * Check for cases where opnd1/opnd2 < n 
228          *
229          * In this case the result's sign will be opposite that of
230          * opnd1.  The mantissa also needs some correction.
231          */
232         Sgl_leftshiftby1(opnd1);
233         if (Sgl_isgreaterthan(opnd1,opnd2)) {
234                 Sgl_invert_sign(result);
235                 Sgl_subtract((opnd2<<1),opnd1,opnd1);
236         }
237         /* check for remainder being exactly 1/2 of opnd2 */
238         else if (Sgl_isequal(opnd1,opnd2) && roundup) { 
239                 Sgl_invert_sign(result);
240         }
241
242         /* normalize result's mantissa */
243         while (Sgl_iszero_hidden(opnd1)) {
244                 dest_exponent--;
245                 Sgl_leftshiftby1(opnd1);
246         }
247         Sgl_set_exponentmantissa(result,opnd1);
248
249         /* 
250          * Test for underflow
251          */
252     testforunderflow:
253         if (dest_exponent <= 0) {
254                 /* trap if UNDERFLOWTRAP enabled */
255                 if (Is_underflowtrap_enabled()) {
256                         /*
257                          * Adjust bias of result
258                          */
259                         Sgl_setwrapped_exponent(result,dest_exponent,unfl);
260                         *dstptr = result;
261                         /* frem is always exact */
262                         return(UNDERFLOWEXCEPTION);
263                 }
264                 /*
265                  * denormalize result or set to signed zero
266                  */
267                 if (dest_exponent >= (1 - SGL_P)) {
268                         Sgl_rightshift_exponentmantissa(result,1-dest_exponent);
269                 }
270                 else {
271                         Sgl_setzero_exponentmantissa(result);
272                 }
273         }
274         else Sgl_set_exponent(result,dest_exponent);
275         *dstptr = result;
276         return(NOEXCEPTION);
277 }