asm-impl.c

#include "asm.h"
#include <string.h>

int64_t asm_add(int64_t a, int64_t b) {
  asm(
    "add %[b], %[a] \t"
    :[a] "+r" (a)
    :[b] "r" (b)
  );
  return a;
}

int asm_popcnt(uint64_t x) {
  int s = 0;
  int i = 0;
  uint64_t temp = 0;
  asm(
    "Loop:t\n"
    "shrq %[i], %[x] \t\n"   //x >>= i
    "movq %[x], %[temp] \t\n" //x -> tempx
    "andq $1, %[temp] \t\n"
    "addl, %[temp], %[s] \t\n" //s+=?1
    "shlq %[i], %[x] \t\n"

    "addi 1, %[i] \t\n"  //循环末尾部分
    "cmpl $64, %[i] \t\n"
    "blt Loop \n"
    :[s] "+r" (s), [i] "+r" (i), [x] "+r" (x), [temp]"+r"(temp)
  );
  return s;
}

/*int asm_popcnt(uint64_t x) {
  int s = 0;
  for (int i = 0; i < 64; i++) {
    if ((x >> i) & 1) s++;
  }
  return s;
}*/

void *asm_memcpy(void *dest, const void *src, size_t n) {
  return memcpy(dest, src, n);
}

int asm_setjmp(asm_jmp_buf env) {
  return setjmp(env);
}

void asm_longjmp(asm_jmp_buf env, int val) {
  longjmp(env, val);
}