The Vitis™ Unified Software Development Environment libraries and device drivers provide standard C library functions, as well as functions to access peripherals. These libraries are automatically configured based on the Microprocessor Software Specification (MSS) file. These libraries and include files are saved in the current project lib and include directories, respectively. The -I and -L options of mb-gcc are used to add these directories to its library search paths.
Standard C Library (libc.a)
The standard C library, libc.a, contains the
standard C functions compiled for the
MicroBlaze™
processor or the
Arm®
(Cortex-A9, Cortex-R5F, Cortex-A53, and Cortex-A72)
processors. You can find the header files corresponding to these C standard functions in
the <XILINX_SDK>/gnu/<processor>/<platform>/<processor-lib>/include
folder, where:
- <vitis> is the Vitis Unified Software Development Environment installation path
- <processor> is either Arm or MicroBlaze
- <platform> is either Solaris (sol), or Windows (nt), or Linux (lin)
- <processor-lib> is either
arm-xilinx-eabiormicroblaze-xilinx-elf
The lib.c directories and functions are:
_ansi.h fastmath.h machine/ reent.h stdlib.h utime.h _syslist.h
fcntl.h malloc.h regdef.h string.h utmp.h ar.h float.h
math.h setjmp.h sys/ assert.h grp.h paths.h signal.h
termios.h ctype.h ieeefp.h process.h stdarg.h time.h dirent.h
imits.h pthread.h stddef.h nctrl.h errno.h locale.h pwd.h
stdio.h unistd.h Programs accessing standard C library functions must be compiled as follows:
- For MicroBlaze processors
mb-gcc <C files> - For
Arm®
Cortex-A9, Cortex-A53/Cortex-A72 (32-bit mode)
processors
arm-none-eabi-gcc <C files> - For
Arm®
Cortex-A53/Cortex-A72
(64-bit mode)
processors
aarch64-none-elf-gcc <C files> - For Cortex-R5F processor
armr5-none-eabi-gcc <C files>
Memory Management Functions
The MicroBlaze processor and
Arm®
(Cortex-A9, Cortex-A53, Cortex-A72, and
Cortex-R5F) processor C libraries support the
standard memory management functions such as malloc(),
calloc(), and free(). Dynamic memory allocation provides memory from the program heap.
The heap pointer starts at low memory and grows toward high memory. The size of the heap
cannot be increased at run time. Therefore an appropriate value must be provided for the
heap size at compile time. The malloc() function
requires the heap to be at least 128 bytes in size to be able to allocate memory
dynamically (even if the dynamic requirement is less than 128 bytes).