Xilinx Standard C Libraries - 2025.2 English - UG643

The standard C library, libc.a, contains the standard C functions compiled for the MicroBlaze and MicroBlaze-V processor or Arm Cortext-A9, Cortex-R5F, Cortex-R52, Cortex-A53, Cortex-A72, and Cortex-A78 processors. You can find the header files corresponding to these C standard functions in the <installation directory>/Xilinx/<release number>/gnu/<processor>/<platform>/<toolchain>/<processor-lib>/usr/include folder where:

• <installation directory>/Xilinx/<release number> is the Vitis Unified Software Development Environment installation path
• <processor> is either Arm, MicroBlaze, or MicroBlaze-V
• <platform> is either Windows (nt) Linux (lin)
• <processor-lib> is aarch64-none, or gcc-arm-none-eabi, or microblazeeb-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    riscv64-unknown-elf

Programs accessing standard C library functions must be compiled as follows:

• For MicroBlaze processors

  mb-gcc <C files>

• For MicroBlaze-V processor

  riscv64-unknown-elf-gcc <C files>

• For Arm Cortex-A9, Cortex-A53, and Cortex-A72 (32-bit mode) processors

  arm-none-eabi-gcc <C files>

• For Arm Cortex-A53, Cortex-A72, and Cortex-A78 (64-bit mode) processors

  aarch64-none-elf-gcc <C files>

• For Cortex-R5F and Cortex-R52 processor

  armr5-none-eabi-gcc <C files>

The MicroBlaze, MicroBlaze-V, Arm Cortex-A9, Cortex-A53, Cortex-A72, Cortex-A78, Cortex-R52, 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 the runtime. 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).