flag.c

/*
 * written by Wei Shuai <cpuwolf@gmail.com> 2021-Oct
 */
#include <stdio.h>
#include <inttypes.h>
#include <string.h>

typedef struct {
	uint64_t b1;
	uint64_t b2;
} SS64;

typedef struct {
	uint64_t buff;
	uint8_t data[8];
} SS;

SS ss;
//d3c4d6eb c3c3d5cf 
const int64_t biglc = -0x302a3c3c14293b2d;


int main(int argn, void * argv)
{
	register int32_t arg2 asm ("esi") = 0xFFFFFFFF;
	register int32_t arg1 asm ("edi") = 0xAAAAAAAA;
	printf("readlonly input=0x%lX\n", biglc );

	asm("endbr64\n\t"
		"movq   %8,%%xmm0\n\t"
		"add    %%edi,%%esi\n\t"
		"mov    %%esi,%%eax\n\t"
		"movzbl %%sil,%%edx\n\t"
		"shl    $0x8,%%eax\n\t"
		"or     %%edx,%%eax\n\t"
		"mov    %%esi,%%edx\n\t"
		"movd   %%eax,%%xmm2\n\t"
		"mov    %%esi,%%eax\n\t"
		"xor    $0xffffffa7,%%edx\n\t"
		"xor    $0xffffffa3,%%eax\n\t"
		"pshuflw $0x0,%%xmm2,%%xmm1\n\t"
		"mov    %%dl,%0\n\t"
		"mov    %%al,%1\n\t"
		"mov    %%esi,%%eax\n\t"
		"pxor   %%xmm1,%%xmm0\n\t"
		"movq   %%xmm0,%2\n\t"
		"xor    $0xffffffe8,%%eax\n\t"
		"mov    %%al,%3\n\t\n\t"
		"mov    %%esi,%%eax\n\t"
		"xor    $0xffffffa1,%%eax\n\t"
		"mov    %%al,%4\n\t\n\t"
		"mov    %%esi,%%eax\n\t"
		"xor    $0xffffffed,%%esi\n\t"
		"xor    $0xffffffa5,%%eax\n\t"
		"mov    %%sil,%5\n\t"
		"mov    %%al,%6\n\t"
		"mov    %%al,%7"	
		: "=m" (ss.data[4]), "=m" (ss.data[0]), "=m" (ss.buff), "=m" (ss.data[1]), "=m" (ss.data[2]), "=m" (ss.data[6]), "=m" (ss.data[3]), "=m" (ss.data[5])
		: "m" (biglc));
	printf("HEX=0x%x 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x\n", ss.data[0], ss.data[1], ss.data[2],ss.data[3],ss.data[4], ss.data[5], ss.data[6]);
	printf("STR=%c %c %c %c %c %c %c\n", ss.data[0], ss.data[1], ss.data[2],ss.data[3],ss.data[4], ss.data[5], ss.data[6]);
	printf("buff=0x%lX\n\n", ss.buff );
	
	SS64 a;
	
	memcpy(&a, &ss, sizeof(a));
	
	a.b1 = ~a.b1;
	a.b2 = ~a.b2;
	printf("0x%lX 0x%lX\n", a.b1, a.b2);
	
	//string terminal
	((SS *)&a)->data[7]=0;
	printf("%s\n", (char *)&a);

}