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<p class="MsoNormal"><span lang="EN-US">Dear All, <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I compiled the following source code:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">typedef unsigned int uint32_t;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">typedef unsigned char uint8_t;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">int rte_atomic32_cmpset(volatile uint32_t *dst, uint32_t exp, uint32_t src)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">{<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> uint8_t res;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> asm volatile(<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> "lock ; "<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> "cmpxchgl %[src], %[dst];"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> "sete %[res];"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> : [res] "=a" (res), /* output */<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> [dst] "=m" (*dst)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> : [src] "r" (src), /* input */<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> "a" (exp),<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> "m" (*dst)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> : "memory"); /* no-clobber list */<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> return res;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">}<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">And got the following IR:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">define dso_local i32 @rte_atomic32_cmpset(i32* %dst, i32 %exp, i32 %src) local_unnamed_addr #0 {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">entry:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> %0 = tail call i8 asm sideeffect "lock ; cmpxchgl $2, $1;sete $0;", "={ax},=*m,r,{ax},*m,~{memory},~{dirflag},~{fpsr},~{flags}"(i32* %dst, i32 %src, i32 %exp, i32* %dst) #1, !srcloc !2<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> %conv = zext i8 %0 to i32<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> ret i32 %conv<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">}<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">However, I found the following 3 information does not match:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">In the assembler template there are 3 operands (prefixed with $)<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">In the constrains, there are 2 outputs and 3 inputs<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1">
<![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">In the parameter list, there are 4 parameters.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Is there some connections between these 3 information? How to interpret them?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Best,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Geng<o:p></o:p></span></p>
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