Chapter 5.
Modifying libgloss
- 5.1.
The Platform Directory
- 5.1.1.
Ensuring the Platform Directory is Configured
- 5.2.
The C Runtime Initialization,
crt0.o
- 5.2.1.
Exception vector setup
- 5.2.2.
The
_start Function and Stack Initialization
- 5.2.3.
Cache Initialization
- 5.2.4.
Clearing BSS
- 5.2.5.
Constructor and Destructor Handling
- 5.2.6.
C Initialization Functions
- 5.2.7.
Invoking the main program
- 5.3.
Standard System Call Implementations
- 5.3.1.
Error Handling
- 5.3.2.
The Global Environment,
environ
- 5.3.3.
Exit a program,
_exit
- 5.3.4.
Closing a file,
close
- 5.3.5.
Transfer Control to a New Process,
execve
- 5.3.6.
Create a new process,
fork
- 5.3.7.
Provide the Status of an Open File,
fstat
- 5.3.8.
Get the Current Process ID,
getpid
- 5.3.9.
Determine the Nature of a Stream,
isatty
- 5.3.10.
Send a Signal,
kill
- 5.3.11.
Rename an existing file,
link
- 5.3.12.
Set Position in a File,
lseek
- 5.3.13.
Open a file,
open
- 5.3.14.
Read from a File,
read
- 5.3.15.
Allocate more Heap,
sbrk
- 5.3.16.
Status of a File (by Name),
stat
- 5.3.17.
Provide Process Timing Information,
times
- 5.3.18.
Remove a File's Directory Entry,
unlink
- 5.3.19.
Wait for a Child Process,
wait
- 5.3.20.
Write to a File,
write
- 5.4.
Reentrant System Call Implementations
- 5.5.
BSP Configuration and Make file;
- 5.5.1.
configure.in for the BSP
- 5.5.2.
Makefile.in for the BSP
- 5.6.
The Default BSP,
libnosys
Any target architecture may need multiple implementations, suited to
different platforms on which the code may run. The connection between
the library and a specific platform is known as a Board
Support Package (BSP). In recent versions of newlib,
BSPs are separated out into their own library, libgloss, the source
for which is in the top level libgloss directory.
For newlib the BSP within libgloss comprises an implementation of
the C runtime initialization, crt0.o, a definition
of one global data structure, and implementation of eighteen system
calls for each platform.
![[Note]](../images/note.png) | Note |
|---|
libgloss is a relatively new addition to newlib. Some older ports
still have the BSP code within the newlib
directory.
|
