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comparison src/audio/SDL_mixer_m68k.c @ 633:873c2598f969

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Add m68k assembly mixing routines
author Patrice Mandin <patmandin@gmail.com>
date Tue, 03 Jun 2003 19:35:10 +0000
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children b8d311d90021
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632:85e104fe14c2 633:873c2598f969
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22
23 /*
24 m68k assembly mix routines
25
26 Patrice Mandin
27 */
28
29 #if defined(__M68000__) && defined(__GNUC__)
30 void SDL_MixAudio_m68k_U8(char* dst, char* src, long len, long volume, char* mix8)
31 {
32 __asm__ __volatile__ (
33
34 "tstl %2\n"
35 " beqs stoploop_u8\n"
36 "mixloop_u8:\n"
37
38 /* Mix a sample */
39
40 " moveq #0,%%d0\n"
41 " moveq #0,%%d1\n"
42
43 " moveb %1@+,%%d0\n" /* d0 = *src++ */
44 " sub #128,%%d0\n" /* d0 -= 128 */
45 " muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
46 " moveb %0@,%%d1\n" /* d1 = *dst */
47 " asr #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
48 " add #128,%%d0\n" /* d0 += 128 */
49
50 " add %%d1,%%d0\n"
51
52 " moveb %4@(%%d0:w),%0@+\n"
53
54 /* Loop till done */
55
56 " subql #1,%2\n"
57 " bhis mixloop_u8\n"
58 "stoploop_u8:\n"
59
60 : /* no return value */
61 : /* input */
62 "a"(dst), "a"(src), "d"(len), "d"(volume), "a"(mix8)
63 : /* clobbered registers */
64 "d0", "d1", "cc", "memory"
65 );
66 }
67
68 void SDL_MixAudio_m68k_S8(char* dst, char* src, long len, long volume)
69 {
70 __asm__ __volatile__ (
71
72 "tstl %2\n"
73 " beqs stoploop_s8\n"
74 " moveq #-128,%%d2\n"
75 " moveq #127,%%d3\n"
76 "mixloop_s8:\n"
77
78 /* Mix a sample */
79
80 " moveq #0,%%d0\n"
81 " moveq #0,%%d1\n"
82
83 " moveb %1@+,%%d0\n" /* d0 = *src++ */
84 " muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
85 " moveb %0@,%%d1\n" /* d1 = *dst */
86 " asr #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
87
88 " add %%d1,%%d0\n"
89
90 " cmp %%d2,%%d0\n"
91 " bges lower_limit_s8\n"
92 " move %%d2,%%d0\n"
93 "lower_limit_s8:\n"
94
95 " cmp %%d3,%%d0\n"
96 " bles upper_limit_s8\n"
97 " move %%d3,%%d0\n"
98 "upper_limit_s8:\n"
99 " moveb %%d0,%0@+\n"
100
101 /* Loop till done */
102
103 " subql #1,%2\n"
104 " bhis mixloop_s8\n"
105 "stoploop_s8:\n"
106
107 : /* no return value */
108 : /* input */
109 "a"(dst), "a"(src), "d"(len), "d"(volume)
110 : /* clobbered registers */
111 "d0", "d1", "d2", "d3", "cc", "memory"
112 );
113 }
114
115 void SDL_MixAudio_m68k_S16MSB(short* dst, short* src, long len, long volume)
116 {
117 __asm__ __volatile__ (
118
119 "tstl %2\n"
120 " beqs stoploop_s16msb\n"
121 " movel #-32768,%%d2\n"
122 " movel #32767,%%d3\n"
123 " lsrl #1,%2\n"
124 "mixloop_s16msb:\n"
125
126 /* Mix a sample */
127
128 " move %1@+,%%d0\n" /* d0 = *src++ */
129 " muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
130 " move %0@,%%d1\n" /* d1 = *dst */
131 " extl %%d1\n" /* extend d1 to 32 bits */
132 " asrl #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
133
134 " addl %%d1,%%d0\n"
135
136 " cmpl %%d2,%%d0\n"
137 " bges lower_limit_s16msb\n"
138 " move %%d2,%%d0\n"
139 "lower_limit_s16msb:\n"
140
141 " cmpl %%d3,%%d0\n"
142 " bles upper_limit_s16msb\n"
143 " move %%d3,%%d0\n"
144 "upper_limit_s16msb:\n"
145 " move %%d0,%0@+\n"
146
147 /* Loop till done */
148
149 " subql #1,%2\n"
150 " bhis mixloop_s16msb\n"
151 "stoploop_s16msb:\n"
152
153 : /* no return value */
154 : /* input */
155 "a"(dst), "a"(src), "d"(len), "d"(volume)
156 : /* clobbered registers */
157 "d0", "d1", "d2", "d3", "cc", "memory"
158 );
159 }
160
161 void SDL_MixAudio_m68k_S16LSB(short* dst, short* src, long len, long volume)
162 {
163 __asm__ __volatile__ (
164
165 "tstl %2\n"
166 " beqs stoploop_s16lsb\n"
167 " movel #-32768,%%d2\n"
168 " movel #32767,%%d3\n"
169 " lsrl #1,%2\n"
170 "mixloop_s16lsb:\n"
171
172 /* Mix a sample */
173
174 " move %1@+,%%d0\n" /* d0 = *src++ */
175 " rorw #8,%%d0\n"
176 " muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
177 " move %0@,%%d1\n" /* d1 = *dst */
178 " rorw #8,%%d1\n"
179 " extl %%d1\n" /* extend d1 to 32 bits */
180 " asrl #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
181
182 " addl %%d1,%%d0\n"
183
184 " cmpl %%d2,%%d0\n"
185 " bges lower_limit_s16lsb\n"
186 " move %%d2,%%d0\n"
187 "lower_limit_s16lsb:\n"
188
189 " cmpl %%d3,%%d0\n"
190 " bles upper_limit_s16lsb\n"
191 " move %%d3,%%d0\n"
192 "upper_limit_s16lsb:\n"
193 " rorw #8,%%d0\n"
194 " move %%d0,%0@+\n"
195
196 /* Loop till done */
197
198 " subql #1,%2\n"
199 " bhis mixloop_s16lsb\n"
200 "stoploop_s16lsb:\n"
201
202 : /* no return value */
203 : /* input */
204 "a"(dst), "a"(src), "d"(len), "d"(volume)
205 : /* clobbered registers */
206 "d0", "d1", "d2", "d3", "cc", "memory"
207 );
208 }
209 #endif
210