AN2094 Freescale Semiconductor / Motorola, AN2094 Datasheet - Page 51

• Manufacturer Part Number: AN2094
• Description: ITU-T G.729 Implementation on StarCore SC140
• Manufacturer: Freescale Semiconductor / Motorola

The global data for all object files generated from the C source code is listed in the .data section, and the text
code in the .text section. In the final executable files, the .data and .text sections are linked together. The
memory start addresses of these sections are listed in the map file (lines 1 and 6 in Example 19).
The .data section contains a subsection for each object file that lists the start address of each global variable
declared in that object file (lines 3, 4, and 5 in Example 19) and the total data size of that object file (line 2). The
size of each global variable is derived by subtracting its address from the address of the next variable listed. The
first line of the .data section also shows the total size of all global variables in all object files.
The .text section contains a subsection for each object file that lists all global functions declared in the file as
well as the start address and total size of the code section for that file. The first line of the .text section indicates
the total size of all code for all object files. The start and end of each global function are denoted as
_functionName and FfunctionName_end respectively; the difference in their addresses indicates the size
of the function. Static functions in a section are not listed in the map file, but their total size in each section is
derived from the listed information. For example, the coder_ld8k.eln section in Example 19 is 4 638 bytes
(size column in line 7). This section contains one global function, coder_ld8k(), which is 2 974 bytes
(difference in the value column of lines 8 and 9). The size of the static functions in this section is 4 638 – 2 974 =
1 664 bytes.
The data in the map file are very detailed, but it is difficult to distinguish the size of the code generated for the
vocoder by the rest of the tester.
An object file can contain both global data and global functions, global functions only, or global data only. For
example, the tab_ld8k.eln object file contains data only (see lines 2 and 13 in Example 19).
Freescale Semiconductor
…
1
…
2
3
4
5
…
6
…
7
8
9
10 0x00016bd0
11 0x00016bd0
12 0x00016c2c
…
13 0x000185c4
…
0x00000200
0x000005f0
0x000005f0
0x00000ff0
0x00001270
0x00010000
0x000159b0
0x00016030
0x00016bce
Value
ITU-T G.729 Implementation on the StarCore™ SC140/SC1400 Cores, Rev. 1
Size
15464 Section: .data
66592 Section: .text
5956
4638
Example 19. Fragments from the Vocoder Map File
92
0
Symbol
Section: .data(obj/tab_ld8k.eln)
Section: .text(obj/coder_ld8k.eln)
Section: .text(obj/corr.eln)
Section: .text(obj/tab_ld8k.eln)
_lspcb1
_lspcb2
_hamwindow
_Coder_ld8k
FCoder_ld8k_end
_Corr_40
FCorr_40_end
References
51