m1lkweed

#include <stdio.h>

#define SIMD_SSE     0x1
#define SIMD_SSE2    0x2
#define SIMD_SSE3    0x4
#define SIMD_SSE4_1  0x8
#define SIMD_SSE4_2  0x10
#define SIMD_AVX     0x20
#define SIMD_AVX2    0x40
#define SIMD_AVX512F 0x80

m1lkweed

#include <stddef.h>

static inline void *memclear(void *dest, size_t len){
	asm inline volatile("call memset"
	                   :
	                   :"r"(dest),
	                    "r"(0),
	                    "r"(len)
	                   :
	);

m1lkweed

#include <inttypes.h>

#define IS_ARRAY(x) _Generic(&x, default: 1, typeof(*x)**: 0)
#define COUNT_OF(x) _Generic(&x, default: (sizeof(x) / sizeof(0[x])), typeof(*x)**: 0)

#define array_to_fatptr(x) ((fatptr_t){.addr = x, .n_elems = (int16_t)COUNT_OF(x)})
#define fatptr_to_ptr(x, type) ((type*)(intptr_t)x.addr)

typedef union fatptr_t{
	void *ptr;

m1lkweed

// works on all architectures and optimization levels in GCC and clang
// Dead code is optimized like running code and may be removed if the
// compiler can prove that no branches will ever reach it.

#define preserve_dead_code(body) ({ \
	__label__ label;            \
	asm goto(""::::label);      \
	if(0)label:{body}           \
	&&label;                    \
})

m1lkweed

// Works in GCC and clang, produces correct results at all optimization levels

// returns the contents of the instruction pointer
#define get_pc() ({                      \
	register void *temp;             \
	asm volatile("call	.+5\n\t" \
	             "pop	%0"      \
		    :"=r"(temp)          \
	);                               \
	temp;                            \

m1lkweed

[[gnu::noinline]] _Bool on_stack(void *addr){
    char stack_check[1];
    return (addr >= (void*)&stack_check[1]); // stack_check[1] is OoB but it produces better assembly
}

m1lkweed

#include <stdio.h>
#include <unistd.h>
#include <termios.h>

int get_pos(int *col, int *line){
	char buf[30]={0};
	int ret, i, pow;
	char ch;
	*line = 0;
	*col = 0;

m1lkweed

#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdbool.h>
#include <linux/kd.h>
#include <sys/ioctl.h>

static int is_a_console(int fd){
	char arg = 0;

m1lkweed

#define sizeof(x) ((size_t)(((typeof(x)*)0)+1))

#include <stdio.h>

struct foo{
	char a,b,c,d,e;
};

int main(){
	printf("%zu\n", sizeof(int));

m1lkweed

#include <stdint.h>

static uint64_t simple_rnd_state = 0xcafef00dd15ea5e5u;

// returns a random 64-bit value
uint64_t simple_rng(void){
	uint64_t x = simple_rnd_state;
	simple_rnd_state = x * 6364136223846793005u;
	x ^= x >> 22;
	return x;