SLAU132Y September 2004 – June 2021
The compiler uses direct initialization to initialize global variables. For example, consider the following C code:
int i = 23;
int a[5] = { 1, 2, 3, 4, 5 };The compiler allocates the variables 'i' and 'a[] to .data section and the initial values are placed directly.
.global i
.data
.align 4
i:
.field 23,32 ; i @ 0
.global a
.data
.align 4
a:
.field 1,32 ; a[0] @ 0
.field 2,32 ; a[1] @ 32
.field 3,32 ; a[2] @ 64
.field 4,32 ; a[3] @ 96
.field 5,32 ; a[4] @ 128Each compiled module that defines static or global variables contains these .data sections. The linker treats the .data section like any other initialized section and creates an output section. In the load-time initialization model, the sections are loaded into memory and used by the program. See Section 7.10.3.5.
In the run-time initialization model, the linker uses the data in these sections to create initialization data and an additional compressed initialization table. The boot routine processes the initialization table to copy data from load addresses to run addresses. See Section 7.10.3.3.