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1
2 /*
3 * M_APM - mapm_sin.c
4 *
5 * Copyright (C) 1999 - 2007 Michael C. Ring
6 *
7 * Permission to use, copy, and distribute this software and its
8 * documentation for any purpose with or without fee is hereby granted,
9 * provided that the above copyright notice appear in all copies and
10 * that both that copyright notice and this permission notice appear
11 * in supporting documentation.
12 *
13 * Permission to modify the software is granted. Permission to distribute
14 * the modified code is granted. Modifications are to be distributed by
15 * using the file 'license.txt' as a template to modify the file header.
16 * 'license.txt' is available in the official MAPM distribution.
17 *
18 * This software is provided "as is" without express or implied warranty.
19 */
20
21 /*
22 * $Id: mapm_sin.c,v 1.17 2007/12/03 01:48:31 mike Exp $
23 *
24 * This file contains the top level (user callable) SIN / COS / TAN
25 * functions.
26 *
27 * $Log: mapm_sin.c,v $
28 * Revision 1.17 2007/12/03 01:48:31 mike
29 * Update license
30 *
31 * Revision 1.16 2002/11/03 21:53:47 mike
32 * Updated function parameters to use the modern style
33 *
34 * Revision 1.15 2001/03/25 20:59:46 mike
35 * move PI stuff to new file
36 *
37 * Revision 1.14 2001/02/07 19:12:14 mike
38 * eliminate MM_skip_limit_PI_check
39 *
40 * Revision 1.13 2000/11/18 11:05:36 mike
41 * minor code re-arrangement in PI AGM
42 *
43 * Revision 1.12 2000/07/11 23:34:42 mike
44 * adjust loop break-out for AGM PI algorithm
45 *
46 * Revision 1.11 2000/07/11 20:19:47 mike
47 * use new algorithm to compute PI (AGM)
48 *
49 * Revision 1.10 2000/05/21 01:07:57 mike
50 * use _sin_cos in _tan function
51 *
52 * Revision 1.9 2000/05/19 17:13:56 mike
53 * use local copies of PI variables & recompute
54 * on the fly as needed
55 *
56 * Revision 1.8 1999/09/21 21:03:06 mike
57 * make sure the sign of 'sin' from M_cos_to_sin is non-zero
58 * before assigning it from the original angle.
59 *
60 * Revision 1.7 1999/09/18 03:27:27 mike
61 * added m_apm_sin_cos
62 *
63 * Revision 1.6 1999/07/09 22:50:33 mike
64 * skip limit to PI when not needed
65 *
66 * Revision 1.5 1999/06/20 23:42:29 mike
67 * use new function for COS function
68 *
69 * Revision 1.4 1999/06/20 19:27:12 mike
70 * changed local static variables to MAPM stack variables
71 *
72 * Revision 1.3 1999/05/17 03:54:56 mike
73 * init globals in TAN function also
74 *
75 * Revision 1.2 1999/05/15 02:18:31 mike
76 * add check for number of decimal places
77 *
78 * Revision 1.1 1999/05/10 20:56:31 mike
79 * Initial revision
80 */
81
82 #include "m_apm_lc.h"
83
84 /****************************************************************************/
85 void m_apm_sin(M_APM r, int places, M_APM a)
86 {
87 M_APM tmp3;
88
89 tmp3 = M_get_stack_var();
90 M_limit_angle_to_pi(tmp3, (places + 6), a);
91 M_5x_sin(r, places, tmp3);
92 M_restore_stack(1);
93 }
94 /****************************************************************************/
95 void m_apm_cos(M_APM r, int places, M_APM a)
96 {
97 M_APM tmp3;
98
99 tmp3 = M_get_stack_var();
100 M_limit_angle_to_pi(tmp3, (places + 6), a);
101 M_4x_cos(r, places, tmp3);
102 M_restore_stack(1);
103 }
104 /****************************************************************************/
105 void m_apm_sin_cos(M_APM sinv, M_APM cosv, int places, M_APM aa)
106 {
107 M_APM tmp5, tmp6, tmp7;
108
109 tmp5 = M_get_stack_var();
110 tmp6 = M_get_stack_var();
111 tmp7 = M_get_stack_var();
112
113 M_limit_angle_to_pi(tmp5, (places + 6), aa);
114 M_4x_cos(tmp7, (places + 6), tmp5);
115
116 /*
117 * compute sin(x) = sqrt(1 - cos(x) ^ 2).
118 *
119 * note that the sign of 'sin' will always be positive after the
120 * sqrt call. we need to adjust the sign based on what quadrant
121 * the original angle is in.
122 */
123
124 M_cos_to_sin(tmp6, (places + 6), tmp7);
125 if (tmp6->m_apm_sign != 0)
126 tmp6->m_apm_sign = tmp5->m_apm_sign;
127
128 m_apm_round(sinv, places, tmp6);
129 m_apm_round(cosv, places, tmp7);
130 M_restore_stack(3);
131 }
132 /****************************************************************************/
133 void m_apm_tan(M_APM r, int places, M_APM a)
134 {
135 M_APM tmps, tmpc, tmp0;
136
137 tmps = M_get_stack_var();
138 tmpc = M_get_stack_var();
139 tmp0 = M_get_stack_var();
140
141 m_apm_sin_cos(tmps, tmpc, (places + 4), a);
142
143 /* tan(x) = sin(x) / cos(x) */
144
145 m_apm_divide(tmp0, (places + 4), tmps, tmpc);
146 m_apm_round(r, places, tmp0);
147 M_restore_stack(3);
148 }
149 /****************************************************************************/
150 void M_limit_angle_to_pi(M_APM rr, int places, M_APM aa)
151 {
152 M_APM tmp7, tmp8, tmp9;
153
154 M_check_PI_places(places);
155
156 tmp9 = M_get_stack_var();
157 m_apm_copy(tmp9, MM_lc_PI);
158
159 if (m_apm_compare(aa, tmp9) == 1) /* > PI */
160 {
161 tmp7 = M_get_stack_var();
162 tmp8 = M_get_stack_var();
163
164 m_apm_add(tmp7, aa, tmp9);
165 m_apm_integer_divide(tmp9, tmp7, MM_lc_2_PI);
166 m_apm_multiply(tmp8, tmp9, MM_lc_2_PI);
167 m_apm_subtract(tmp9, aa, tmp8);
168 m_apm_round(rr, places, tmp9);
169
170 M_restore_stack(3);
171 return;
172 }
173
174 tmp9->m_apm_sign = -1;
175 if (m_apm_compare(aa, tmp9) == -1) /* < -PI */
176 {
177 tmp7 = M_get_stack_var();
178 tmp8 = M_get_stack_var();
179
180 m_apm_add(tmp7, aa, tmp9);
181 m_apm_integer_divide(tmp9, tmp7, MM_lc_2_PI);
182 m_apm_multiply(tmp8, tmp9, MM_lc_2_PI);
183 m_apm_subtract(tmp9, aa, tmp8);
184 m_apm_round(rr, places, tmp9);
185
186 M_restore_stack(3);
187 return;
188 }
189
190 m_apm_copy(rr, aa);
191 M_restore_stack(1);
192 }
193 /****************************************************************************/