<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html lang="en" style="--code-editor-font: var(--default-mono-font, "GitLab Mono"), JetBrains Mono, Menlo, DejaVu Sans Mono, Liberation Mono, Consolas, Ubuntu Mono, Courier New, andale mono, lucida console, monospace;">
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
<title>
GitLab
</title>
<style data-premailer="ignore" type="text/css">
a { color: #1068bf; }
</style>
<style>img {
max-width: 100%; height: auto;
}
body {
font-size: .875rem;
}
body {
-webkit-text-shadow: hsla(0,0%,100%,.01) 0 0 1px;
}
body {
font-family: "GitLab Sans",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans",Ubuntu,Cantarell,"Helvetica Neue",sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji"; font-size: inherit;
}
</style>
</head>
<body style="font-size: inherit; -webkit-text-shadow: hsla(0,0%,100%,.01) 0 0 1px; font-family: "GitLab Sans",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans",Ubuntu,Cantarell,"Helvetica Neue",sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";">
<div class="content">
<p style="color: #777777;">
<a href="https://gitlab.rtems.org/sebhub">Sebastian Huber</a>
commented on a
discussion on <a href="https://gitlab.rtems.org/rtems/rtos/rtems/-/merge_requests/1452#note_158216">testsuites/validation/tc-score-isr.c</a>:
</p>
<table class="code gl-mb-5" style="border-spacing: 0; margin-bottom: 1rem; border-collapse: collapse; width: auto; font-family: monospace; font-size: 90%;" bgcolor="#ffffff" width="100%" cellpadding="0" cellspacing="0">
<tr class="line_holder old" style="line-height: 1.6;">
<td class="old_line diff-line-num old" data-linenumber="138" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
138
</td>
<td class="new_line diff-line-num old" data-linenumber="138" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
</td>
<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">-<span class="line" data-lang="c"> <span class="k" style="font-weight: 600;">register</span> <span class="kt" style="color: #445588; font-weight: 600;">uintptr_t</span> <span class="n" style="color: #333333;">sp</span> <span class="n" style="color: #333333;">__asm__</span><span class="p">(</span> <span class="s" style="color: #dd1144;">"1"</span> <span class="p">);</span></span>
</pre></td>
</tr>
<tr class="line_holder old" style="line-height: 1.6;">
<td class="old_line diff-line-num old" data-linenumber="139" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
139
</td>
<td class="new_line diff-line-num old" data-linenumber="138" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
</td>
<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">-<span class="line" data-lang="c"></span>
</pre></td>
</tr>
<tr class="line_holder" style="line-height: 1.6;">
<td class="old_line diff-line-num" data-linenumber="140" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
140
</td>
<td class="new_line diff-line-num" data-linenumber="138" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #ececef; border-right-style: solid; padding: inherit;" align="right" bgcolor="#fbfafd">
138
</td>
<td class="line_content" style="padding: inherit;"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;"> <span class="line" data-lang="c"> <span class="k" style="font-weight: 600;">if</span> <span class="p">(</span> <span class="n" style="color: #333333;">interrupted_stack_at_multitasking_start</span> <span class="o" style="font-weight: 600;">==</span> <span class="mi" style="color: #009999;">0</span> <span class="p">)</span> <span class="p">{</span></span>
</pre></td>
</tr>
<tr class="line_holder old" style="line-height: 1.6;">
<td class="old_line diff-line-num old" data-linenumber="141" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
141
</td>
<td class="new_line diff-line-num old" data-linenumber="139" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #fac5cd; border-right-style: solid; padding: inherit;" align="right" bgcolor="#f9d7dc">
</td>
<td class="line_content old" style="padding: inherit;" bgcolor="#fbe9eb"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">-<span class="line" data-lang="c"> <span class="n" style="color: #333333;">interrupted_stack_at_multitasking_start</span> <span class="o" style="font-weight: 600;">=</span> <span class="n" style="color: #333333;">sp</span><span class="p">;</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="139" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
139
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="k" style="font-weight: 600;">const</span> <span class="n" style="color: #333333;">Per_CPU_Control</span> <span class="o" style="font-weight: 600;">*</span><span class="n" style="color: #333333;">cpu_self</span><span class="p">;</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="140" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
140
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="k" style="font-weight: 600;">const</span> <span class="kt" style="color: #445588; font-weight: 600;">uintptr_t</span> <span class="o" style="font-weight: 600;">*</span><span class="n" style="color: #333333;">frame</span><span class="p">;</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="141" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
141
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
142
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="cm" style="color: #999988; font-style: italic;">/*</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="143" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
143
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"><span class="cm" style="color: #999988; font-style: italic;"> * The dispatch runs on the interrupt stack. The switch to that stack</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="144" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
144
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"><span class="cm" style="color: #999988; font-style: italic;"> * stores the stack pointer of the interrupted context at the begin of the</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="145" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
145
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"><span class="cm" style="color: #999988; font-style: italic;"> * frame at the top of the interrupt stack.</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="146" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
146
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"><span class="cm" style="color: #999988; font-style: italic;"> */</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="147" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
147
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="n" style="color: #333333;">cpu_self</span> <span class="o" style="font-weight: 600;">=</span> <span class="n" style="color: #333333;">_Per_CPU_Get</span><span class="p">();</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="148" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
148
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="n" style="color: #333333;">frame</span> <span class="o" style="font-weight: 600;">=</span> <span class="p">(</span><span class="k" style="font-weight: 600;">const</span> <span class="kt" style="color: #445588; font-weight: 600;">uintptr_t</span> <span class="o" style="font-weight: 600;">*</span><span class="p">)</span> <span class="p">(</span> <span class="p">(</span><span class="kt" style="color: #445588; font-weight: 600;">uintptr_t</span><span class="p">)</span> <span class="n" style="color: #333333;">cpu_self</span><span class="o" style="font-weight: 600;">-></span><span class="n" style="color: #333333;">interrupt_stack_high</span> <span class="o" style="font-weight: 600;">-</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="149" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
149
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="n" style="color: #333333;">CPU_INTERRUPT_FRAME_SIZE</span> <span class="p">);</span></span>
</pre></td>
</tr>
<tr class="line_holder new" style="line-height: 1.6;">
<td class="old_line diff-line-num new" data-linenumber="142" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
</td>
<td class="new_line diff-line-num new" data-linenumber="150" style="width: 35px; color: rgba(5,5,6,.24); border-right-width: 1px; border-right-color: #c7f0d2; border-right-style: solid; padding: inherit;" align="right" bgcolor="#ddfbe6">
150
</td>
<td class="line_content new" style="padding: inherit;" bgcolor="#ecfdf0"><pre style="display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: inherit; border-radius: 2px; margin: 0; padding: 0; border: inherit solid #dcdcde;">+<span class="line" data-lang="c"> <span class="n" style="color: #333333;">interrupted_stack_at_multitasking_start</span> <span class="o" style="font-weight: 600;">=</span> <span class="o" style="font-weight: 600;">*</span><span class="n" style="color: #333333;">frame</span><span class="p">;</span></span>
</pre></td>
</tr>
</table>
<div class="md" style="position: relative; z-index: 1; color: #3a383f; word-wrap: break-word;">
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial">Neither r1 nor r3. The word at offset 0 of this frame is not a saved
register. The interrupt path builds two frames and only one of them holds
saved registers.</p>
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial"><code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0px; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">_interrupt_handler.S</code> builds the first frame on the stack of the
interrupted context. It saves r3 to r18 and the MSR. The
<code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">MICROBLAZE_INTERRUPT_FRAME_*</code> offsets describe this frame.</p>
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial"><code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0px; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">_ISR_Handler</code> then tests whether the stack pointer is inside the interrupt
stack. If it is not, <code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">switch_to_interrupt_stack</code> builds a second frame at
the top of the interrupt stack:</p>
<div class="gl-relative markdown-code-block js-markdown-code">
<pre class="code highlight js-syntax-highlight language-plaintext" v-pre="true" style="display: block; font-size: 90%; color: #3a383f; line-height: 1.6em; overflow-x: auto; border-radius: .25rem; position: relative; font-family: monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #ffffff; -premailer-cellpadding: 0; -premailer-cellspacing: 0; -premailer-width: 100%; margin: 0px 0 1rem; padding: 12px; border: 1px solid #dcdcde;"><code style="font-size: inherit; color: inherit; word-wrap: normal; word-break: keep-all; background-color: inherit; border-radius: .25rem; white-space: pre; margin-top: 0px; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; overflow-wrap: normal; padding: unset;"><span id="LC1" class="line" lang="plaintext" style="margin-top: 0px;">switch_to_interrupt_stack:</span>
<span id="LC2" class="line" lang="plaintext"> add r4, r0, r1 /* base of the first frame */</span>
<span id="LC3" class="line" lang="plaintext"> lwi r1, r0, _Per_CPU_Information + 4 /* interrupt_stack_high */</span>
<span id="LC4" class="line" lang="plaintext"> addik r1, r1, -(CPU_INTERRUPT_FRAME_SIZE)</span>
<span id="LC5" class="line" lang="plaintext"> swi r4, r1, 0</span></code></pre>
<copy-code></copy-code><insert-code-snippet></insert-code-snippet>
</div>
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial">The return path reads the same word back to leave the interrupt stack:</p>
<div class="gl-relative markdown-code-block js-markdown-code">
<pre class="code highlight js-syntax-highlight language-plaintext" v-pre="true" style="display: block; font-size: 90%; color: #3a383f; line-height: 1.6em; overflow-x: auto; border-radius: .25rem; position: relative; font-family: monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #ffffff; -premailer-cellpadding: 0; -premailer-cellspacing: 0; -premailer-width: 100%; margin: 0px 0 1rem; padding: 12px; border: 1px solid #dcdcde;"><code style="font-size: inherit; color: inherit; word-wrap: normal; word-break: keep-all; background-color: inherit; border-radius: .25rem; white-space: pre; margin-top: 0px; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; overflow-wrap: normal; padding: unset;"><span id="LC1" class="line" lang="plaintext" style="margin-top: 0px;"> lwi r1, r1, 0</span></code></pre>
<copy-code></copy-code><insert-code-snippet></insert-code-snippet>
</div>
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial">The second frame reuses the size of the first frame. It does not reuse the
layout. Its only member is the stack pointer of the interrupted context at
offset 0. That is the word the test reads. The saved r3 sits in the first
frame at a different address on the interrupted stack.</p>
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial">The value the test gets is the base of the first frame, that is the
interrupted stack pointer minus 56. The test checks membership in the
initial stack area of the thread, so the offset makes no difference.</p>
<p dir="auto" style="color: #3a383f; margin: 0px 0px 1rem;" align="initial">The collision of <code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0px; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">MICROBLAZE_INTERRUPT_FRAME_R3</code> with offset 0 is what makes
this hard to read. I can add a name for the offset in <code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">cpuimpl.h</code>:</p>
<div class="gl-relative markdown-code-block js-markdown-code">
<pre class="code highlight js-syntax-highlight language-plaintext" v-pre="true" style="display: block; font-size: 90%; color: #3a383f; line-height: 1.6em; overflow-x: auto; border-radius: .25rem; position: relative; font-family: monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #ffffff; -premailer-cellpadding: 0; -premailer-cellspacing: 0; -premailer-width: 100%; margin: 0px 0 1rem; padding: 12px; border: 1px solid #dcdcde;"><code style="font-size: inherit; color: inherit; word-wrap: normal; word-break: keep-all; background-color: inherit; border-radius: .25rem; white-space: pre; margin-top: 0px; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; overflow-wrap: normal; padding: unset;"><span id="LC1" class="line" lang="plaintext" style="margin-top: 0px;">/*</span>
<span id="LC2" class="line" lang="plaintext"> * The frame at the top of the interrupt stack stores the stack pointer</span>
<span id="LC3" class="line" lang="plaintext"> * of the interrupted context at this offset.</span>
<span id="LC4" class="line" lang="plaintext"> */</span>
<span id="LC5" class="line" lang="plaintext">#define MICROBLAZE_INTERRUPT_FRAME_SP 0</span></code></pre>
<copy-code></copy-code><insert-code-snippet></insert-code-snippet>
</div>
<p dir="auto" style="color: #3a383f; margin: 0px;" align="initial">Then <code style="font-size: 90%; color: #18171d; word-wrap: break-word; background-color: #ececef; border-radius: .25rem; margin-top: 0px; font-weight: inherit; overflow-wrap: break-word; white-space: break-spaces; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: keep-all; padding: 0.125rem 0.25rem;">cpu_asm.S</code> and this test use the name instead of a bare 0. Tell me if
you want that and I add it as a preparation commit.</p>
</div>
</div>
<div class="footer" style="margin-top: 10px;">
<p style="font-size: small; color: #626168;">
—
<br>
<a href="https://gitlab.rtems.org/rtems/rtos/rtems/-/merge_requests/1452#note_158216">View it on GitLab</a>.
<br>
You're receiving this email because of your account on <a target="_blank" rel="noopener noreferrer" href="https://gitlab.rtems.org">gitlab.rtems.org</a>. <a href="https://gitlab.rtems.org/-/sent_notifications/5-d4tadc3q9fyw9n12tsewhth7f-1d/unsubscribe" target="_blank" rel="noopener noreferrer">Unsubscribe</a> from this thread · <a href="https://gitlab.rtems.org/-/profile/notifications" target="_blank" rel="noopener noreferrer" class="mng-notif-link">Manage all notifications</a> · <a href="https://gitlab.rtems.org/help" target="_blank" rel="noopener noreferrer" class="help-link">Help</a>
<span style="color: transparent; font-size: 0; display: none; overflow: hidden; opacity: 0; width: 0; height: 0; max-width: 0; max-height: 0;">
Notification message regarding https://gitlab.rtems.org/rtems/rtos/rtems/-/merge_requests/1452#note_158216 at 1787875686
</span>
<script type="application/ld+json">{"@context":"http://schema.org","@type":"EmailMessage","action":{"@type":"ViewAction","name":"View Merge request","url":"https://gitlab.rtems.org/rtems/rtos/rtems/-/merge_requests/1452#note_158216"}}</script>
</p>
</div>
</body>
</html>