Update bbox_elf_dump_base.cpp

src/gausskernel/cbb/bbox/bbox_elf_dump_base.cpp

@@ -44,11 +44,22 @@ static int g_iPosBlackList = 0;
 /* array store for black list */
 static BBOX_BLACKLIST_STRU g_stBlackList[BBOX_BLACK_LIST_COUNT_MAX];
 
-/*
- * Determines whether the byte order of the local machine is large or small
- * return :  ELFDATA2LSB - large
- *        :  ELFDATA2MSB - small
- */
+  /*
+function name: BBOX_DetermineMsb
+description: The function should judge the mode that PC uses to store data is  Big-endian/Little-endian.
+arguments: void
+return value: An integer that indicates the mode is Big-endian/Little-endian,
+					 if it is ELFDATA2LSB, the mode is Little-endian,
+                     if it is ELFDATA2MSB, the mode is Big-endian.
+note：The way that this function judge the mode that PC uses to store data is through a union variable unProbe, 
+		   at first we give its first member variable sShortInt a value BBOX_MSB_LSB_INT of type short, then its second 
+           member variable cSplit[sizeof(short)] equaling to cSplit[2] would have the equal value of the first. Finally we 
+           just need to compare BBOX_LITTER_BITS and BBOX_HIGH_BITS, namely the low byte and high byte of 
+           BBOX_MSB_LSB_INT, with unProbe.cSplit[0] and unProbe.cSplit[1], if they are correspondingly equal, the mode is
+           Little-endian, else is the Big-endian.
+date: 2022/8/2
+contact tel: 18720816902
+  */
 int BBOX_DetermineMsb(void)
 {
     union INT_PROBE {