ft_libasm

42 Libasm reimplements selected libc functions in hand-rolled x86-64 NASM assembly for Linux (System V AMD64 ABI).

Build

Requirements: nasm, gcc, and libbsd-dev for the C test driver.

make help           # list Makefile targets
make                # mandatory libasm.a and libasm_test
make bonus          # rebuild libasm.a with bonus symbols
make re             # clean rebuild
make fclean         # remove generated files

make is the canonical 42 build. CMake is available for IDEs:

cmake -S . -B build && cmake --build build

Validate

make test           # mandatory functions and read/write error paths
make test_bonus     # ft_atoi_base and linked-list bonuses
valgrind --leak-check=full --error-exitcode=1 ./libasm_test
valgrind --leak-check=full --error-exitcode=1 ./libasm_bonus_test

make test_bonus leaves libasm.a with bonus symbols. Return to the mandatory archive with:

make fclean && make

Manual checks

Build the interactive driver, which exercises all mandatory functions:

make manual
./libasm_manual
printf 'hello from stdin\n' | ./libasm_manual

Inspect the archive and function symbols:

ar t libasm.a
readelf -sW libasm.a | grep ' ft_'

Trace the test driver's real read(2) and write(2) calls, or debug an assembly function:

strace -e trace=read,write ./libasm_test
gdb ./libasm_test
# (gdb) break ft_strlen
# (gdb) run

API

Headers: include/libasm.h and include/libasm_bonus.h. Link client code with -Iinclude -L. -lasm.

Notes

• Source: NASM Intel syntax, 64-bit only.
• ft_read and ft_write return -1 and set errno on syscall failure.
• Bonus sources are _bonus.s files under src/bonus/.
• docs/ contains ABI, x86-64, NASM, and reference notes.