alexwern/libft_asm

HIVE Helsinki project Libft but in Assembly.

Libft_ASM

The aim of this project is for me to learn more about x64 Assembly and at the side since Libft is used in
the school projects maybe I can have an excuse to use this and get some sort of performance gain from it. So far most functions seem to have some performance gain when compared to C version. Most notably ft_bzero is 10 times faster which is little mind boggling and makes me question if I can improve the C version. If anything, using optimization flags is kinda sometimes forbidden maybe (it's so hazy if it is or not and I'd rather not twist hands about it) so if I just write the assembly like -OX then it's fine right?
As more recent thing, I've been reading through AMD64 Architecture Programmer’s Manuals and picked up some fancy instructions and now I have a small subset of Libft_ASM original functions that use those instructions.
You will need Make and NASM to compile which you can grab from https://www.nasm.us/ or install through Linux packages. Just run make in terminal and you can link the libft_asm.a to your program. libft_asm.h is the related C header.
Do note that Windows passes arguments to functions in different registers than on Lunix/Mac so none of these actually work on Windows for now. Also interrupts in general are apparently a different world but that an issue for time when I have the first version done in its entirety.

TODO

1. Create first versions of all basic Libft functions. Proper comments and descriptions included.
2. Windows uses different registers to pass arguments to functions so port them over. It's a bit of work but most of the time it only involves swapping registers around.
3. New functions! This is assembly and there's an entire world of things I can do here that are not implemented in C/C++ so I'm going to take full use of that.
4. Own malloc. First I need to get the C version done but once that exists the ASM version should be easier to do since I have a proper ground to work on. I did some testing on just MMAP and it has massive overhead which I'm definitely not a fan of so I need the entire malloc around it.

Libft Functions

Function Name	Done?
abs	YES
atoi	Kinda
atof	YES
bzero	YES
intsize	YES
isalnum	YES
isalpha	YES
isascii	YES
isblank	YES
isdigit	YES
isextascii	X
isnegative	YES
isprint	YES
itoa	X
lcm	X
listlen	YES
memalloc	YES
memccpy	YES
memchr	YES
memcmp	YES
memcpy	YES
memdel	YES
memmove	YES
memset	YES
printmem	X
putchar	YES
putchar_fd	YES
putendl	YES
putendl_fd	YES
puthex	YES
puthexln	YES
putnbr	X
putnbrln	X
putnbr_fd	X
putstr	YES
putstr_fd	YES
quadjoin	YES
realloc	Kinda
splitfree	YES
strcat	YES
strchr	YES
strclr	YES
strcmp	YES
strcpy	YES
strdel	YES
strdup	YES
strequ	YES
strfjoin	YES
striter	YES
striteri	YES
strjoin	YES
strlcat	YES
strlen	YES
strmap	X
strmapi	X
strncat	YES
strncmp	YES
strncpy	YES
strnequ	YES
strnew	X
strnstr	YES
strrchr	YES
strsjoin	YES
strsplit	X
strstr	YES
strsub	X
strtrim	X
tolower	YES
toupper	YES
wordlen	YES
get_next_line	X

Libft_ASM Original Functions

Function Name	Description
bswap	Swaps byte order betweeen little and big endian
rotate_left	Rotates num left by n bits. Overflow rolls back to right end
rotate_right	Rotates num right by n bits. Overflow rolls back to left end

Issues

1. Atoi doesn't follow the standard and skip over blank characters at the start.
2. Realloc makes any further malloc uses sometimes crash with "malloc(): corrupted top size". The exact reason is unknown.