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150
lang/src/int_to_str.asm
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@ -1,155 +1,5 @@
section .text
global int_to_str
global int_to_str2
global str_to_int
;; rdi: pointer to input string
;; rsi: length of input string
;; dl: radix
;; fn str_to_int(s: *const u8, len: usize, radix: u8) -> i64
str_to_int:
push rbp
mov rbp, rsp
push r12
push r13
sub rsp, 0x10
mov qword [rsp], 0 ; result = 0
mov [rsp + 8], dl ; multiplier = radix
xor r12, r12 ; r12 = index
.loop:
cmp r12, rsi
jge .epilogue
mov rax, [rsp]
movzx rcx, byte [rsp + 8]
xor rdx, rdx
imul rcx
jo .overflow ; overflow
mov [rsp], rax
mov al, byte [rdi + r12]
cmp al, '_'
je .skip_underscore
cmp al, '9'
ja .check_alpha
cmp al, '0'
jb .not_a_digit
sub al, '0'
jmp .digit_parsed
.check_alpha:
cmp al, 'a'
jb .not_a_digit
cmp al, 'f'
ja .not_a_digit
sub al, 'a' - 10
jmp .digit_parsed
.digit_parsed:
cmp al, byte [rsp + 8]
ja .not_a_digit
movzx rax, al
add [rsp], rax
.skip_underscore:
inc r12
jmp .loop
.not_a_digit:
mov qword [rsp], 0
jmp .epilogue
.overflow:
mov rax, -1
shr rax, 1
mov qword [rsp], rax
.epilogue:
mov rax, [rsp]
add rsp, 0x10
pop r13
pop r12
pop rbp
ret
;; rdi: input integer
;; rsi: pointer to output buffer (at least 21 bytes)
;; rdx: length of buffer
;; cl: radix
;; fn int_to_str2(value: i64, buffer: *mut u8, len: usize, radix: u8) -> (*mut u8, usize)
int_to_str2:
push rbp
mov rbp, rsp
push r12
push r13
sub rsp, 0x20
mov [rsp], rdi ; save value
mov [rsp + 8], rdx ; save length
mov [rsp + 16], rcx ; save radix
xor r12, r12 ; r12 = index
test rdx, rdx
jz .epilogue ; if length is 0, return
xor r13, r13
mov rcx, rdi
sar rcx, 63 ; check sign
cmp rcx, 0
je .convert
.negative:
mov byte [rsi], '-' ; write minus sign
neg rdi
inc r13
inc r12
.convert:
test rdi, rdi
jnz .convert_loop
mov byte [rsi + r12], '0'
jmp .epilogue
.convert_loop:
mov rax, [rsp + 8] ; buffer length
cmp r12, rax
jge .epilogue ; prevent buffer overflow
mov rax, rdi
xor rdx, rdx
mov rcx, [rsp + 16] ; base 10
mov cl, cl
div rcx ; rax = rdi / radix, rdx = rdi % radix
cmp rdx, 10
jl .decimal
add rdx, 'a' - 10 ; convert to 'a'-'f'
jmp .phi
.decimal:
add rdx, '0' ; convert digit to ASCII
.phi:
mov byte [rsi + r12], dl
inc r12
mov rdi, rax
test rdi, rdi
jnz .convert_loop
; Reverse the digits
mov rdx, r12
dec r12 ; last digit index
.reverse_loop:
cmp r13, r12
jae .done_reverse
mov al, [rsi + r13]
mov bl, [rsi + r12]
mov [rsi + r13], bl
mov [rsi + r12], al
inc r13
dec r12
jmp .reverse_loop
.done_reverse:
mov rax, rsi
.epilogue:
add rsp, 0x20
pop r13
pop r12
pop rbp
ret
;; Converts integer in rcx to string at rdx
;; rcx: input integer

80
lang/tests/int_to_str.rs
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@ -1,80 +0,0 @@
#[unsafe(no_mangle)]
extern "C" fn panic() -> ! {
panic!("Called panic from external code.");
}
#[repr(C)]
struct FFISlice {
ptr: *const u8,
len: usize,
}
impl FFISlice {
fn as_slice(&self) -> &[u8] {
unsafe { core::slice::from_raw_parts(self.ptr, self.len) }
}
fn as_str(&self) -> &str {
unsafe { core::str::from_utf8_unchecked(self.as_slice()) }
}
}
unsafe extern "C" {
unsafe fn int_to_str2(value: isize, buffer: *mut u8, buffer_len: usize, radix: u8) -> FFISlice;
unsafe fn str_to_int(s: *const u8, len: usize, radix: u8) -> isize;
}
fn main() {
let value = 1234567890isize;
let mut buffer = [0u8; 32];
unsafe {
let slice = int_to_str2(value, buffer.as_mut_ptr(), buffer.len(), 10);
let s = slice.as_str();
println!("Integer: {}, String: {}", value, s);
assert_eq!(s, format!("{value}"));
let slice = int_to_str2(0 - value, buffer.as_mut_ptr(), buffer.len(), 10);
let s = slice.as_str();
println!("Integer: {}, String: {}", 0 - value, s);
assert_eq!(s, format!("{}", 0 - value));
let slice = int_to_str2(value, buffer.as_mut_ptr(), buffer.len(), 16);
let s = slice.as_str();
println!("Integer: {:x}, String: {}", value, s);
assert_eq!(s, format!("{value:x}"));
let slice = int_to_str2(value, buffer.as_mut_ptr(), buffer.len(), 8);
let s = slice.as_str();
println!("Integer: {:o}, String: {}", value, s);
assert_eq!(s, format!("{value:o}"));
let value = 235isize;
let slice = int_to_str2(value, buffer.as_mut_ptr(), buffer.len(), 2);
let s = slice.as_str();
println!("Integer: {:b}, String: {}", value, s);
assert_eq!(s, format!("{value:b}"));
let s = "1234567890";
let parsed = str_to_int(s.as_ptr(), s.len(), 10);
println!("String: {}, Integer: {}", s, parsed);
assert_eq!(parsed, 1234567890isize);
let s = "499602d2";
let parsed = str_to_int(s.as_ptr(), s.len(), 16);
println!("String: {}, Integer: {}", s, parsed);
assert_eq!(parsed, 1234567890isize);
let s = "11145401322";
let parsed = str_to_int(s.as_ptr(), s.len(), 8);
println!("String: {}, Integer: {}", s, parsed);
assert_eq!(parsed, 1234567890isize);
let s = "11101011";
let parsed = str_to_int(s.as_ptr(), s.len(), 2);
println!("String: {}, Integer: {}", s, parsed);
assert_eq!(parsed, 235isize);
let s = "9999999999999999999999999999999999999999";
let parsed = str_to_int(s.as_ptr(), s.len(), 10);
println!("String: {}, Integer: {}", s, parsed);
assert_eq!(parsed, isize::MAX);
}
}