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<p>Hey Levente,</p>
<p>I am trying to primitize the #findErrorLocations: &
#findErrorMagnitudes:errorLocations: methods. I thought I had it
done, but I am getting a segfault when running the
RSFECReedSolomonTest>>#testDataMatrix test. I tried to dig
into it and find out the issue. I think one of the params to the
primitive is nil. The strange thing I observed is a debug stack in
Squeak, where the argument to the prior stack frame is an
instance, but the argument in the top frame is nil. I do not
understand how it can go from type -> nil.</p>
<p>If you wish to help me figure this out, the current RSFEC code is
loaded with:</p>
<blockquote>
<p>Installer ss<br/>
project: 'Cryptography';<br/>
install: 'ProCrypto-1-1-1';<br/>
install: 'ProCryptoTests-1-1-1'.<br/>
</p>
</blockquote>
<p>Then the Decoder primitives to RSFECPlugin is loaded from:</p>
<blockquote>
<p>CryptographyRSFECPluginsDecoder-segfault-rww.2<br/>
</p>
</blockquote>
<div class="moz-signature">---<br/>
Kindly,<br/>
Robert<br/>
<br/>
<br/>
</div>
<div class="moz-cite-prefix">On 6/2/21 10:40 AM, Levente Uzonyi
wrote:<br/>
</div>
<blockquote type="cite" cite="mid:alpine.DEB.2.02.2106021613320.10584@login03.caesar.elte.hu">
<pre class="moz-quote-pre" wrap="">Hi Robert,
On Tue, 1 Jun 2021, Robert Withers wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Hey ya, Levente,
Woot!!! I was able to get all the primitives working with ByteArrays. Everything is passing green! (except for several GF fields: Aztec and Maxicode and QRCode) I think I will primitize one of the codingLoops on the RSErasure
side. Here are the numbers. Take note of the tallies and time: 50 seconds versus 114 seconds. I updated the squeak wiki Cryptography page (<a class="moz-txt-link-freetext" href="http://wiki.squeak.org/squeak/5776">http://wiki.squeak.org/squeak/5776</a>) with d/l links to the plugins. Here are those
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">Brilliant. ByteArray is indeed the optimal choice there.
Let me answer your question in your previous email here:
AFAIK, on all the currently supported platforms and C compilers, unsigned
int is 32-bits, so it matches WordArray in Squeak.
DoubleWordArray is 64-bits, and in C that matches the type unsigned long long (on the currently supported platforms and compilers).
I think you can shave off a few more seconds there by adding those
<inline: #always> pragmas to the methods the primitive methods send
either directly or indirectly.
And, I think the logTable and expTable variables can be declared as
constant as well as unsigned char arrays instead of unsigned int arrays.
That might give more opportunities to the C compiler to optimize the code.
I prefer to use #var:type:array: instead of #var:declareC: when possible.
E.g.
cg
var: #logTable declareC: 'unsigned int logTable[256] = {
0, 0, 1, 240, 2, 225, 241, 53, 3, 38, 226, 133, 242, 43, 54, 210, 4, 195,
39, 114, 227, 106, 134, 28, 243, 140, 44, 23, 55, 118, 211, 234, 5, 219,
196, 96, 40, 222, 115, 103, 228, 78, 107, 125, 135, 8, 29, 162, 244, 186,
141, 180, 45, 99, 24, 49, 56, 13, 119, 153, 212, 199, 235, 91, 6, 76, 220,
217, 197, 11, 97, 184, 41, 36, 223, 253, 116, 138, 104, 193, 229, 86, 79,
171, 108, 165, 126, 145, 136, 34, 9, 74, 30, 32, 163, 84, 245, 173, 187,
204, 142, 81, 181, 190, 46, 88, 100, 159, 25, 231, 50, 207, 57, 147, 14,
67, 120, 128, 154, 248, 213, 167, 200, 63, 236, 110, 92, 176, 7, 161, 77,
124, 221, 102, 218, 95, 198, 90, 12, 152, 98, 48, 185, 179, 42, 209, 37,
132, 224, 52, 254, 239, 117, 233, 139, 22, 105, 27, 194, 113, 230, 206,
87, 158, 80, 189, 172, 203, 109, 175, 166, 62, 127, 247, 146, 66, 137,
192, 35, 252, 10, 183, 75, 216, 31, 83, 33, 73, 164, 144, 85, 170, 246,
65, 174, 61, 188, 202, 205, 157, 143, 169, 82, 72, 182, 215, 191, 251, 47,
178, 89, 151, 101, 94, 160, 123, 26, 112, 232, 21, 51, 238, 208, 131, 58,
69, 148, 18, 15, 16, 68, 17, 121, 149, 129, 19, 155, 59, 249, 70, 214,
250, 168, 71, 201, 156, 64, 60, 237, 130, 111, 20, 93, 122, 177, 150 }';
could be written as
cg
var: #logTable
type: #'const unsigned char'
array: #[0 0 1 240 2 225 241 53 3 38 226 133 242 43 54
210 4 195 39 114 227 106 134 28 243 140 44 23 55 118 211 234 5 219 196 96
40 222 115 103 228 78 107 125 135 8 29 162 244 186 141 180 45 99 24 49 56
13 119 153 212 199 235 91 6 76 220 217 197 11 97 184 41 36 223 253 116 138
104 193 229 86 79 171 108 165 126 145 136 34 9 74 30 32 163 84 245 173 187
204 142 81 181 190 46 88 100 159 25 231 50 207 57 147 14 67 120 128 154
248 213 167 200 63 236 110 92 176 7 161 77 124 221 102 218 95 198 90 12
152 98 48 185 179 42 209 37 132 224 52 254 239 117 233 139 22 105 27 194
113 230 206 87 158 80 189 172 203 109 175 166 62 127 247 146 66 137 192 35
252 10 183 75 216 31 83 33 73 164 144 85 170 246 65 174 61 188 202 205 157
143 169 82 72 182 215 191 251 47 178 89 151 101 94 160 123 26 112 232 21
51 238 208 131 58 69 148 18 15 16 68 17 121 149 129 19 155 59 249 70 214
250 168 71 201 156 64 60 237 130 111 20 93 122 177 150]
Levente
</pre>
</blockquote>
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