SterlingOS/sterling/exemple/exemple.stg

it should look more like c, as i want my compiler to be able to compile c

#include <io.sterling>//sterling is the name of the language, but i need to think of a file extension name that doesn't conflict with other format
#include <string.h>//this should work

u32	add(u32 a, u32 b) {
	return (a + b);
}

// also i should be able as the user to define

typedef struct {
	u32	test = 12;
} new_struct;
// if new_struct struct = {0}; then all data even default init are set to 0
// but if new_struct struct = {}; then all data but default init are set to 0

//also pointer should work like c, but void* shouldn't be the same as ptr*
//i don't know what i could do, but i would like for ptr* to allow for implicite data cast, but void* should be explicit

meta	define_add(T);
T add(T a, T b) {
	return (a + b);
}
//the issue i have here is it need to have an explicit overload if T is a structure, and i don't really like it, could lead to a c++ like language with too many undefined behavior, what could be a better approach ?


#include <io.stgh>//for stg header but i could also just use .stg and have the possibility to include stg file as header
#include <string.h>

typedef struct {
	u32	x = 1;
	u32	y = 2;
} vec2;

typedef struct {
	u32	x;
	u32	y;
} vec2_raw;

u32	add(u32 a, u32 b) {
	return (a + b);
}

vec2_raw make_raw(u32 a, u32 b) {
	return (vec2_raw){ a, b };
}

void* memcpy_explicit(void* dst, void* src, u32 n) {
	// must explicitly cast outside
	return memcpy(dst, src, n);
}

fn copy(ptr* dst, ptr* src, u32 n) {
	// compiler auto-casts any ptr* to void* internally
	memcpy(dst, src, n);
}

meta define_add(T);
T add(T a, T b) {
	return (a + b);
}

// specialization for vec2
meta define_add(vec2);
vec2 add(vec2 a, vec2 b) {
	return (vec2){ a.x + b.x, a.y + b.y };
}

fn main() -> u32 {
	vec2 a = {};		// defaults apply
	vec2 b = {0};		// defaults ignored, all zero

	vec2 result = add(a, b);

	u32* data = 0;
	copy(data, data, 4);		// OK
	memcpy_explicit((void*)data, (void*)data, 4); // must cast

	return 0;
}

fn_asm	exit() {
	section .text
	global exit
	exit:
		mov rax, 60 ; syscall for exit
		mov rdi, 0 ; exit code
		syscall
		ret
}

/*
	rdi: dst
	rsi: value
	rdx: size
	Returns in rax: dst
*/
/*  implicit
	section .text
	global <symbol>
	memset:
*/
fn_asm memset(void* dst, u8 value, u64 size) {
	test rdx, rdx
	je .done

	mov rax, rsi        ; value
	mov rdi, rdi        ; dst
	mov rcx, rdx        ; size

	rep stosb

.done:
	mov rax, rdi        ; return dst
	ret
}
//This uses the rep stosb instruction to rapidly write bytes into memory.

/*
	rdi: void** old_sp — destination to store current rsp
	rsi: void* new_sp — new stack pointer to switch into
	No return value (control flow continues on new stack)
*/
fn_asm context_switch(void** old_sp, void* new_sp) {
	mov [rdi], rsp     ; save current stack pointer to *old_sp
	mov rsp, rsi       ; load new stack pointer
	ret
}


/*
	rdi: dst
	rsi: value
	rdx: size
	Returns in rax: dst
*/
/*  implicit
	section .text
	memset:
*/
fn_static_asm memset(void* dst, u8 value, u64 size) {
	test rdx, rdx
	je .done

	mov rax, rsi        ; value
	mov rdi, rdi        ; dst
	mov rcx, rdx        ; size

	rep stosb

.done:
	mov rax, rdi        ; return dst
	ret
}
//This uses the rep stosb instruction to rapidly write bytes into memory.

/*
| Keyword         | Description                                                            |
| --------------- | ---------------------------------------------------------------------- |
| `fn`            | Required for every function definition                                 |
| `fn_inline`     | Inline-only function, callable in the same TU                          |
| `fn_static`     | Internal linkage (only visible in current TU)                          |
| `fn_extern`     | Declaration only; expects symbol at link time                          |
| `fn_export`     | Visible outside, exported in shared/static libs                        |
| `fn_asm`        | Assembly-defined function, globally visible unless otherwise specified |
| `fn_static_asm` | Assembly-defined, internal linkage (hidden from linker)                |
*/

//Keyword Examples

// header file (user_math.stgh)
fn_extern add(u32, u32);
fn_inline max(u32 a, u32 b) {
	return (a > b) ? a : b;
}

// libmath.stg
fn_export add(u32 a, u32 b) {
	return a + b;
}

// internal use only
fn_static log2_floor(u32 x) {
	// implementation
}

// inline asm
fn_asm fast_add(u32 a, u32 b) {
	mov eax, edi
	add eax, esi
	ret
}

// internal-only asm
fn_static_asm zero_block(void* dst, u64 size) {
	rep stosb
	ret
}