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Diffstat (limited to 'apps/plugins/lib/gray_scroll_down.c')
-rw-r--r--apps/plugins/lib/gray_scroll_down.c134
1 files changed, 0 insertions, 134 deletions
diff --git a/apps/plugins/lib/gray_scroll_down.c b/apps/plugins/lib/gray_scroll_down.c
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--- a/apps/plugins/lib/gray_scroll_down.c
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1/***************************************************************************
2* __________ __ ___.
3* Open \______ \ ____ ____ | | _\_ |__ _______ ___
4* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
7* \/ \/ \/ \/ \/
8* $Id$
9*
10* Grayscale framework
11* gray_scroll_down() function
12*
13* This is a generic framework to use grayscale display within Rockbox
14* plugins. It obviously does not work for the player.
15*
16* Copyright (C) 2004 Jens Arnold
17*
18* All files in this archive are subject to the GNU General Public License.
19* See the file COPYING in the source tree root for full license agreement.
20*
21* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
22* KIND, either express or implied.
23*
24****************************************************************************/
25
26#ifndef SIMULATOR /* not for simulator by now */
27#include "plugin.h"
28
29#if CONFIG_LCD == LCD_SSD1815 /* only for Recorder/Ondio */
30#include "gray.h"
31
32/*---------------------------------------------------------------------------
33 Scroll the whole grayscale buffer down by <count> pixels (<= 7)
34 ----------------------------------------------------------------------------
35 black_border determines if the pixels scrolled in at the top are black
36 or white
37
38 Scrolling up/down pixel-wise is significantly slower than scrolling
39 left/right or scrolling up/down byte-wise because it involves bit
40 shifting. That's why it is asm optimized.
41 */
42void gray_scroll_down(int count, bool black_border)
43{
44 unsigned filler;
45
46 if ((unsigned) count > 7)
47 return;
48
49 filler = black_border ? (0xFFu << count) : 0;
50
51 /* scroll column by column to minimize flicker */
52 asm volatile (
53 "mov #0,r6 \n" /* x = 0 */
54 "mova .sd_shifttbl,r0 \n" /* calculate jump destination for */
55 "mov.b @(r0,%6),%6 \n" /* shift amount from table */
56 "bra .sd_cloop \n" /* skip table */
57 "add r0,%6 \n"
58
59 ".align 2 \n"
60 ".sd_shifttbl: \n" /* shift jump offset table */
61 ".byte .sd_shift0 - .sd_shifttbl \n"
62 ".byte .sd_shift1 - .sd_shifttbl \n"
63 ".byte .sd_shift2 - .sd_shifttbl \n"
64 ".byte .sd_shift3 - .sd_shifttbl \n"
65 ".byte .sd_shift4 - .sd_shifttbl \n"
66 ".byte .sd_shift5 - .sd_shifttbl \n"
67 ".byte .sd_shift6 - .sd_shifttbl \n"
68 ".byte .sd_shift7 - .sd_shifttbl \n"
69
70 ".sd_cloop: \n" /* repeat for every column */
71 "mov %1,r2 \n" /* get start address */
72 "mov #0,r3 \n" /* current_plane = 0 */
73
74 ".sd_oloop: \n" /* repeat for every bitplane */
75 "mov r2,r4 \n" /* get start address */
76 "mov #0,r5 \n" /* current_row = 0 */
77 "mov %5,r1 \n" /* get filler bits */
78
79 ".sd_iloop: \n" /* repeat for all rows */
80 "shlr8 r1 \n" /* shift right to get residue */
81 "mov.b @r4,r0 \n" /* get data byte */
82 "jmp @%6 \n" /* jump into shift "path" */
83 "extu.b r0,r0 \n" /* extend unsigned */
84
85 ".sd_shift6: \n" /* shift left by 0..7 bits */
86 "shll2 r0 \n"
87 ".sd_shift4: \n"
88 "shll2 r0 \n"
89 ".sd_shift2: \n"
90 "bra .sd_shift0 \n"
91 "shll2 r0 \n"
92 ".sd_shift7: \n"
93 "shll2 r0 \n"
94 ".sd_shift5: \n"
95 "shll2 r0 \n"
96 ".sd_shift3: \n"
97 "shll2 r0 \n"
98 ".sd_shift1: \n"
99 "shll r0 \n"
100 ".sd_shift0: \n"
101
102 "or r0,r1 \n" /* combine with last residue */
103 "mov.b r1,@r4 \n" /* store data */
104 "add %2,r4 \n" /* address += width */
105 "add #1,r5 \n" /* current_row++ */
106 "cmp/hi r5,%3 \n" /* current_row < bheight ? */
107 "bt .sd_iloop \n"
108
109 "add %4,r2 \n" /* start_address += plane_size */
110 "add #1,r3 \n" /* current_plane++ */
111 "cmp/hi r3,%0 \n" /* current_plane < depth ? */
112 "bt .sd_oloop \n"
113
114 "add #1,%1 \n" /* start_address++ */
115 "add #1,r6 \n" /* x++ */
116 "cmp/hi r6,%2 \n" /* x < width ? */
117 "bt .sd_cloop \n"
118 : /* outputs */
119 : /* inputs */
120 /* %0 */ "r"(_graybuf->depth),
121 /* %1 */ "r"(_graybuf->data),
122 /* %2 */ "r"(_graybuf->width),
123 /* %3 */ "r"(_graybuf->bheight),
124 /* %4 */ "r"(_graybuf->plane_size),
125 /* %5 */ "r"(filler),
126 /* %6 */ "r"(count)
127 : /* clobbers */
128 "r0", "r1", "r2", "r3", "r4", "r5", "r6"
129 );
130}
131
132#endif // #ifdef HAVE_LCD_BITMAP
133#endif // #ifndef SIMULATOR
134
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