[Valgrind-developers] valgrind/coregrind/x86

[Jeremy F. <je...@go...>]

CVS commit by fitzhardinge: 

Add some comments


  M +9 -4      ume_go.c   1.3


--- valgrind/coregrind/x86/ume_go.c  #1.2:1.3
@@ -27,9 +27,14 @@
 #include "ume_arch.h"
 
+/* 
+   Jump to a particular EIP with a particular ESP.  This is intended
+   to simulate the initial CPU state when the kernel starts an program
+   after exec; it therefore also clears all the other registers.
+ */
 void ume_go(addr_t eip, addr_t esp)
 {
-   asm volatile ("movl %1, %%esp;"
-                 "pushl %%eax;"
-                 "xorl  %%eax,%%eax;"
+   asm volatile ("movl %1, %%esp;"      /* set esp */
+                 "pushl %%eax;"         /* push esp */
+                 "xorl  %%eax,%%eax;"   /* clear registers */
                  "xorl  %%ebx,%%ebx;"
                  "xorl  %%ecx,%%ecx;"
@@ -43,4 +48,4 @@ void ume_go(addr_t eip, addr_t esp)
    /* we should never get here */
    for(;;)
-           ;
+           asm volatile("ud2");
 }