Hello all,
My name is Ethin and I am new to this community. However, I certainly
am no newbie when it comes to software development, and have emailed
all of you to file a proposal of inline assembly in Swift. The
assembly language would be within an asm {...} block. The asm keyword
could also take an optional argument: the type of assembler to use. As
there are many different types of assemblers out there, I thought this
should be implemented as well. Furthermore, the asm keyword could also
take a second optional argument: the extra arguments to pass to the
assembler. The full syntax of the keyword would look something like:
asm (assembler, assembler_args)
{
// asm goes here...
}
For instance, below is a hello world application in NASM assembly
language (taken from Wikipedia) with no extra arguments for Linux:
asm ("nasm")
{
global _start
section .text
_start:
mov eax, 4 ; write
mov ebx, 1 ; stdout
mov ecx, msg
mov edx, msg.len
int 0x80 ; write(stdout, msg, strlen(msg));
mov eax, 1 ; exit
mov ebx, 0
int 0x80 ; exit(0)
section .data
msg: db "Hello, world!", 10
.len: equ $ - msg
}
And here is one for Mac OS X with the -G, -Fstabs, and -felf arguments to nasm:
asm ("nasm", "-G -Fstabs -felf")
{
global _start
section .data
query_string: db "Enter a character: "
query_string_len: equ $ - query_string
out_string: db "You have input: "
out_string_len: equ $ - out_string
section .bss
in_char: resw 4
section .text
_start:
mov rax, 0x2000004 ; put the write-system-call-code into
register rax
mov rdi, 1 ; tell kernel to use stdout
mov rsi, query_string ; rsi is where the kernel expects to
find the
address of the message
mov rdx, query_string_len ; and rdx is where the kernel expects to
find the length of the message
syscall
; read in the character
mov rax, 0x2000003 ; read system call
mov rdi, 0 ; stdin
mov rsi, in_char ; address for storage, declared in
section .bss
mov rdx, 2 ; get 2 bytes from the kernel's
buffer (one for the
carriage return)
syscall
; show user the output
mov rax, 0x2000004 ; write system call
mov rdi, 1 ; stdout
mov rsi, out_string
mov rdx, out_string_len
syscall
mov rax, 0x2000004 ; write system call
mov rdi, 1 ; stdout
mov rsi, in_char
mov rdx, 2 ; the second byte is to apply
the carriage return
expected in the string
syscall
; exit system call
mov rax, 0x2000001 ; exit system call
xor rdi, rdi
syscall
}
Again, both assembly language examples were taken from Wikipedia. I am
no asm expert, I assure you, and with the lack of material available
on assembly language these days... it's quite hard to learn it. I
thank you for taking your time to read this proposal and have a nice
day!
--
Signed,
Ethin D. Probst
_______________________________________________
swift-evolution mailing list
[email protected]
https://lists.swift.org/mailman/listinfo/swift-evolution
