/[gxemul]/trunk/src/cpus/experiment_arm_multi.c
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Contents of /trunk/src/cpus/experiment_arm_multi.c

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Revision 18 - (show annotations)
Mon Oct 8 16:19:11 2007 UTC (13 years ago) by dpavlin
File MIME type: text/plain
File size: 4543 byte(s)
++ trunk/HISTORY	(local)
$Id: HISTORY,v 1.1004 2005/10/27 14:01:10 debug Exp $
20051011        Passing -A as the default boot arg for CATS (works fine with
                OpenBSD/cats).
20051012	Fixing the VGA cursor offset bug, and speeding up framebuffer
		redraws if character cells contain the same thing as during
		the last redraw.
20051013	Adding a slow strd ARM instruction hack.
20051017	Minor updates: Adding a dummy i80321 Verde controller (for
		XScale emulation), fixing the disassembly of the ARM "ldrd"
		instruction, adding "support" for less-than-4KB pages for ARM
		(by not adding them to translation tables).
20051020	Continuing on some HPCarm stuff. A NetBSD/hpcarm kernel prints
		some boot messages on an emulated Jornada 720.
		Making dev_ram work better with dyntrans (speeds up some things
		quite a bit).
20051021	Automatically generating some of the most common ARM load/store
		multiple instructions.
20051022	Better statistics gathering for the ARM load/store multiple.
		Various other dyntrans and device updates.
20051023	Various minor updates.
20051024	Continuing; minor device and dyntrans fine-tuning. Adding the
		first "reasonable" instruction combination hacks for ARM (the
		cores of NetBSD/cats' memset and memcpy).
20051025	Fixing a dyntrans-related bug in dev_vga. Also changing the
		dyntrans low/high access notification to only be updated on
		writes, not reads. Hopefully it will be enough. (dev_vga in
		charcell mode now seems to work correctly with both reads and
		writes.)
		Experimenting with gathering dyntrans statistics (which parts
		of emulated RAM that are actually executed), and adding
		instruction combination hacks for cache cleaning and a part of
		NetBSD's scanc() function.
20051026	Adding a bitmap for ARM emulation which indicates if a page is
		(specifically) user accessible; loads and stores with the t-
		flag set can now use the translation arrays, which results in
		a measurable speedup.
20051027	Dyntrans updates; adding an extra bitmap array for 32-bit
		emulation modes, speeding up the check whether a physical page
		has any code translations or not (O(n) -> O(1)). Doing a
		similar reduction of O(n) to O(1) by avoiding the scan through
		the translation entries on a translation update (32-bit mode
		only).
		Various other minor hacks.
20051029	Quick release, without any testing at all.

==============  RELEASE 0.3.6.2  ==============


1 /*
2 * Copyright (C) 2005 Anders Gavare. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 *
28 * $Id: experiment_arm_multi.c,v 1.1 2005/10/22 09:38:46 debug Exp $
29 *
30 * Given a list of common ARM load/store multiple opcodes, figure out (using
31 * simple brute force), which n bits (where n is low, e.g. 7) that cause the
32 * best separation of the 24 bit opcode space into linear lists, where "best"
33 * means to optimize the length of the longest such linear list.
34 *
35 * The result is a set of bits, such as this:
36 *
37 * xxxx100P USWLnnnn llllllll llllllll
38 * ^ ^ ^^ ^^ (in this case, n = 6)
39 *
40 * (it's a 24-bit space, because the s-bit isn't used).
41 */
42
43 #include <stdio.h>
44 #include <stdlib.h>
45
46
47 int bit_count(unsigned int x)
48 {
49 static const int c[16] = { 0,1,1,2, 1,2,2,3, 1,2,2,3, 2,3,3,4 };
50 return c[x & 15] + c[(x>>4) & 15] +
51 c[(x>>8) & 15] + c[(x>>12) & 15] +
52 c[(x>>16) & 15] + c[(x>>20) & 15] +
53 c[(x>>24) & 15] + c[(x>>28) & 15];
54 }
55
56
57 int cmpfunc(const void *a, const void *b)
58 {
59 int *pa = (int *) a, *pb = (int *) b;
60 if (*pa < *pb)
61 return -1;
62 if (*pa > *pb)
63 return 1;
64 return 0;
65 }
66
67
68 int calc_max_list_length(int *opcodes, int *tmp_table,
69 int n_opcodes, int bit_mask)
70 {
71 int i, maxlen, curlen;
72
73 for (i=0; i<n_opcodes; i++)
74 tmp_table[i] = opcodes[i] & bit_mask;
75
76 qsort(tmp_table, n_opcodes, sizeof(int), cmpfunc);
77 curlen = maxlen = 1;
78
79 for (i=1; i<n_opcodes; i++)
80 if (tmp_table[i] == tmp_table[i-1]) {
81 curlen ++;
82 if (curlen > maxlen)
83 maxlen = curlen;
84 } else
85 curlen = 1;
86
87 return maxlen;
88 }
89
90
91 int main(int argc, char *argv[])
92 {
93 FILE *f = fopen("cpu_arm_multi.txt", "r");
94 int n;
95 const int max = 10000;
96 int opcode[max];
97 int tmp_table[max];
98 int n_opcodes = 0;
99 int *max_len;
100 int bit_mask, best_bit_mask, best_bit_mask_len;
101
102 if (argc < 2) {
103 fprintf(stderr, "usage: %s n\n", argv[0]);
104 fprintf(stderr, "where n=6 might be a good choice\n");
105 exit(1);
106 }
107
108 n = atoi(argv[1]);
109
110 if (f == NULL) {
111 fprintf(stderr, "could not open cpu_arm_multi.txt\n");
112 exit(1);
113 }
114
115 /* Read the opcodes: */
116 while (!feof(f)) {
117 char s[100];
118 s[0] = s[sizeof(s)-1] = '\0';
119 fgets(s, sizeof(s), f);
120 if (s[0] == '0') {
121 if (n_opcodes > max) {
122 fprintf(stderr, "too many opcodes\n");
123 exit(1);
124 }
125 opcode[n_opcodes++] = strtol(s, NULL, 0);
126 }
127 }
128
129 printf("nr of opcodes = %i\n", n_opcodes);
130
131 max_len = malloc(sizeof(int) * (1 << 25));
132 if (max_len == NULL) {
133 fprintf(stderr, "out of memory\n");
134 exit(1);
135 }
136
137 best_bit_mask_len = -1;
138
139 for (bit_mask = 0; bit_mask <= 0x01ffffff; bit_mask ++) {
140 /* Skip the s-bit: */
141 if (bit_mask & 0x00400000)
142 continue;
143
144 if (bit_count(bit_mask) != n)
145 continue;
146
147 /* Calculate the max list length for this bit_mask: */
148 max_len[bit_mask] = calc_max_list_length(opcode,
149 tmp_table, n_opcodes, bit_mask);
150
151 if (best_bit_mask_len == -1 ||
152 max_len[bit_mask] < best_bit_mask_len) {
153 best_bit_mask_len = max_len[bit_mask];
154 best_bit_mask = bit_mask;
155 printf("best bit_mask so far: 0x%08x: %i\n",
156 best_bit_mask, best_bit_mask_len);
157 }
158 }
159
160 return 0;
161 }
162

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