user: What is the c source code of the assembly code below:

```asm
<grisu3_parse_double>:
  endbr64
  push   %r15
  lea    0x3e9(%rdi),%r11
  push   %r14
  push   %r13
  mov    %rdx,%r13
  push   %r12
  push   %rbp
  mov    %rdi,%rbp
  push   %rbx
  sub    $0x8,%rsp
  movq   $0x0,(%rdx)
  cmp    $0x3e8,%esi
  jg     L226
  add    $0x1,%esi
  movslq %esi,%rsi
  lea    (%rdi,%rsi,1),%r11
L226:
  cmp    %rbp,%r11
  je     L449
  movzbl 0x0(%rbp),%r10d
  cmp    $0x2d,%r10b
  je     L610
  cmp    $0x30,%r10b
  je     L130
  lea    -0x31(%r10),%eax
  cmp    $0x8,%al
  ja     L449
  mov    %rbp,%rdx
  xor    %r12d,%r12d
L652:
  sub    $0x30,%r10d
  lea    0x1(%rdx),%rbx
  movsbl %r10b,%r10d
L141:
  cmp    %r11,%rbx
  je     L702
  mov    D7(%rip),%rax
  mov    %rbx,%rdx
  movslq (%rax),%rdi
  mov    %rdi,%rax
  imul   $0x66666667,%rdi,%rdi
  sar    $0x1f,%eax
  sar    $0x22,%rdi
  sub    %eax,%edi
  jmp    L692
  nopl   0x0(%rax,%rax,1)
L105:
  cmp    %r10d,%edi
  jle    L578
  lea    (%r10,%r10,4),%ecx
  add    $0x1,%rdx
  lea    -0x30(%rax,%rcx,2),%r10d
  cmp    %rdx,%r11
  je     L702
L692:
  movsbl (%rdx),%eax
  lea    -0x30(%rax),%ecx
  cmp    $0x9,%cl
  jbe    L105
  xor    %r14d,%r14d
L655:
  cmp    %rdx,%r11
  je     L702
  mov    %rdx,%rsi
  xor    %r8d,%r8d
  jmp    L586
  cs nopw 0x0(%rax,%rax,1)
L547:
  add    $0x1,%rsi
  add    $0x1,%r8d
  cmp    %rsi,%r11
  je     L702
  movzbl (%rsi),%eax
L586:
  cmp    $0x30,%al
  je     L547
  cmp    %rsi,%r11
  je     L702
  lea    -0x31(%rax),%ecx
  cmp    $0x8,%cl
  jbe    L426
L440:
  sub    %rbx,%rdx
  mov    %edx,%r9d
  cmp    $0x2e,%al
  je     L553
L706:
  add    %r9d,%r8d
L354:
  or     $0x20,%eax
  cmp    $0x65,%al
  je     L489
L467:
  push   %r13
  mov    %r10d,%ecx
  mov    %r12d,%edx
  mov    %rbp,%rdi
  push   %r14
  call   <grisu3_encode_double@plt>
  pop    %rdx
  pop    %rcx
L166:
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L489:
  mov    %r11,%rax
  sub    %rsi,%rax
  cmp    $0x1,%rax
  jle    L702
  movzbl 0x1(%rsi),%eax
  cmp    $0x2b,%al
  je     L175
  cmp    $0x2d,%al
  je     L12
  lea    0x1(%rsi),%rdx
  xor    %ecx,%ecx
L72:
  sub    $0x30,%eax
  cmp    $0x9,%al
  ja     L702
  lea    0x1(%rdx),%rsi
  movsbl %al,%eax
  cmp    %rsi,%r11
  jne    L334
  jmp    L480
  xchg   %ax,%ax
L74:
  cmp    $0x7fff,%eax
  jg     L246
  lea    (%rax,%rax,4),%eax
  lea    -0x30(%rdx,%rax,2),%eax
L246:
  add    $0x1,%rsi
  cmp    %rsi,%r11
  je     L480
L334:
  movsbl (%rsi),%edx
  lea    -0x30(%rdx),%edi
  cmp    $0x9,%dil
  jbe    L74
  test   %ecx,%ecx
  je     L173
L209:
  neg    %eax
L173:
  add    %eax,%r8d
  cmp    %rsi,%r11
  jne    L467
  nopl   0x0(%rax)
L702:
  xor    %eax,%eax
L337:
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L466:
  mov    %r13,%rcx
  mov    %r12d,%edx
  mov    %r11,%rsi
  mov    %rbx,%rdi
  call   <grisu3_parse_hex_fp@plt>
  cmp    %rax,%rbx
  jne    L166
L449:
  add    $0x8,%rsp
  mov    %rbp,%rax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   (%rax)
L610:
  lea    0x1(%rbp),%rdx
  cmp    %rdx,%r11
  je     L702
  movzbl 0x1(%rbp),%r10d
  cmp    $0x30,%r10b
  je     L137
  lea    -0x31(%r10),%ecx
  xor    %eax,%eax
  mov    $0x1,%r12d
  cmp    $0x8,%cl
  jbe    L652
  jmp    L166
  xchg   %ax,%ax
L130:
  mov    %rbp,%rdx
  xor    %r12d,%r12d
L647:
  lea    0x1(%rdx),%rbx
  xor    %eax,%eax
  cmp    %rbx,%r11
  je     L166
  movzbl 0x1(%rdx),%eax
  mov    %eax,%edx
  or     $0x20,%edx
  cmp    $0x78,%dl
  jne    L564
  jmp    L466
  nopl   0x0(%rax,%rax,1)
L87:
  add    $0x1,%rbx
  cmp    %rbx,%r11
  je     L702
  movzbl (%rbx),%eax
L564:
  cmp    $0x30,%al
  je     L87
  xor    %r10d,%r10d
  jmp    L141
  nopl   0x0(%rax)
L137:
  mov    $0x1,%r12d
  jmp    L647
  nopl   0x0(%rax,%rax,1)
L578:
  xor    %ecx,%ecx
  cmp    $0x34,%al
  mov    $0x1,%r14d
  setg   %cl
  add    %ecx,%r10d
  jmp    L655
  nopl   (%rax)
L553:
  movsbl 0x1(%rsi),%eax
  lea    0x1(%rsi),%r9
  lea    -0x30(%rax),%ecx
  cmp    $0x9,%cl
  ja     L702
  mov    %r9,%rcx
  lea    (%r8,%r9,1),%r15d
  cmp    %r9,%r11
  jne    L653
  jmp    L702
  nopl   (%rax)
L556:
  cmp    %r10d,%edi
  jle    L422
  lea    (%r10,%r10,4),%esi
  add    $0x1,%rcx
  lea    -0x30(%rax,%rsi,2),%r10d
  cmp    %rcx,%r11
  je     L702
  movsbl (%rcx),%eax
L653:
  mov    %r15d,%r8d
  lea    -0x30(%rax),%esi
  mov    %ecx,%ebx
  sub    %ecx,%r8d
  cmp    $0x9,%sil
  jbe    L556
L464:
  cmp    %rcx,%r11
  je     L702
  mov    %r8d,%edi
  mov    %rcx,%rsi
  sub    %ebx,%edi
  jmp    L663
  cs nopw 0x0(%rax,%rax,1)
L119:
  add    $0x1,%rsi
  cmp    %rsi,%r11
  je     L702
  movzbl (%rsi),%eax
L663:
  lea    (%rdi,%rsi,1),%r8d
  cmp    $0x30,%al
  je     L119
  cmp    %rsi,%r11
  je     L702
  sub    %r9,%rcx
  lea    (%rdx,%rcx,1),%r9d
  lea    -0x31(%rax),%edx
  cmp    $0x8,%dl
  ja     L706
  nopl   0x0(%rax)
L650:
  add    $0x1,%rsi
  cmp    %rsi,%r11
  je     L702
  movzbl (%rsi),%eax
  lea    -0x30(%rax),%edx
  cmp    $0x9,%dl
  jbe    L650
  add    %r9d,%r8d
  cmp    %rsi,%r11
  je     L702
  mov    $0x1,%r14d
  jmp    L354
  nopw   0x0(%rax,%rax,1)
L426:
  add    $0x1,%rsi
  lea    0x1(%r8),%r9d
  sub    %esi,%r9d
  cmp    %rsi,%r11
  jne    L408
  jmp    L702
  nopl   (%rax)
L615:
  add    $0x1,%rsi
  cmp    %rsi,%r11
  je     L702
L408:
  movzbl (%rsi),%eax
  lea    (%r9,%rsi,1),%r8d
  lea    -0x30(%rax),%ecx
  cmp    $0x9,%cl
  jbe    L615
  cmp    %rsi,%r11
  je     L702
  mov    $0x1,%r14d
  jmp    L440
L175:
  lea    0x2(%rsi),%rdx
  cmp    %rdx,%r11
  je     L702
  movzbl 0x2(%rsi),%eax
  xor    %ecx,%ecx
  jmp    L72
L480:
  test   %ecx,%ecx
  jne    L209
  xor    %eax,%eax
  jmp    L337
  nop
L422:
  test   %r14d,%r14d
  jne    L464
  xor    %esi,%esi
  cmp    $0x34,%al
  mov    $0x1,%r14d
  setg   %sil
  add    %esi,%r10d
  jmp    L464
L12:
  lea    0x2(%rsi),%rdx
  cmp    %rdx,%r11
  je     L702
  movzbl 0x2(%rsi),%eax
  mov    $0x1,%ecx
  jmp    L72
```

assistant: ```c
const char *grisu3_parse_double(const char *buf, int len, double *result) {
  const char *mark, *k, *end;
  int sign = 0, esign = 0;
  uint64_t fraction = 0;
  int exponent = 0;
  int ee = 0;
  int fraction_exp = 0;
  int ulp_half_error = 0;
  *result = 0.0;
  end = buf + len + 1;
  if (len > 1000) {
    end = buf + 1000 + 1;
  }
  if (buf == end) {
    return buf;
  }
  mark = buf;
  if (*buf == '-') {
    ++buf;
    sign = 1;
    if (buf == end) {
      return 0;
    }
  }
  if (*buf == '0') {
    ++buf;
    if (buf != end && (*buf | 0x20) == 'x') {
      k = grisu3_parse_hex_fp(buf, end, sign, result);
      if (k == buf) {
        return mark;
      }
      return k;
    }
    while (buf != end && *buf == '0') {
      ++buf;
    }
  } else {
    if (*buf < '1' || *buf > '9') {
      return sign ? 0 : mark;
    }
    fraction = *buf++ - '0';
  }
  k = buf;
  while (buf != end && *buf >= '0' && *buf <= '9') {
    if (fraction >= UINT64_MAX / 10) {
      fraction += *buf >= '5';
      ulp_half_error = 1;
      break;
    }
    fraction = fraction * 10 + *buf++ - '0';
  }
  fraction_exp = (int)(buf - k);
  while (buf != end && *buf == '0') {
    ++exponent;
    ++buf;
  }
  if (buf != end && *buf >= '1' && *buf <= '9') {
    ulp_half_error = 1;
    ++exponent;
    ++buf;
    while (buf != end && *buf >= '0' && *buf <= '9') {
      ++exponent;
      ++buf;
    }
  }
  if (buf != end && *buf == '.') {
    ++buf;
    k = buf;
    if (*buf < '0' || *buf > '9') {
      return 0;
    }
    while (buf != end && *buf >= '0' && *buf <= '9') {
      if (fraction >= UINT64_MAX / 10) {
        if (!ulp_half_error) {
          fraction += *buf >= '5';
          ulp_half_error = 1;
        }
        break;
      }
      fraction = fraction * 10 + *buf++ - '0';
      --exponent;
    }
    fraction_exp += (int)(buf - k);
    while (buf != end && *buf == '0') {
      ++exponent;
      ++buf;
    }
    if (buf != end && *buf >= '1' && *buf <= '9') {
      ulp_half_error = 1;
      ++buf;
      while (buf != end && *buf >= '0' && *buf <= '9') {
        ++buf;
      }
    }
  }
  exponent += fraction_exp;
  if (buf != end && (*buf | 0x20) == 'e') {
    if (end - buf < 2) {
      return 0;
    }
    ++buf;
    if (*buf == '+') {
      ++buf;
      if (buf == end) {
        return 0;
      }
    } else if (*buf == '-') {
      esign = 1;
      ++buf;
      if (buf == end) {
        return 0;
      }
    }
    if (*buf < '0' || *buf > '9') {
      return 0;
    }
    ee = *buf++ - '0';
    while (buf != end && *buf >= '0' && *buf <= '9') {
      if (ee <= 0x7fff) {
        ee = ee * 10 + *buf - '0';
      }
      ++buf;
    }
  }
  exponent = exponent + (esign ? -ee : ee);
  if (buf == end) {
    return 0;
  }
  return grisu3_encode_double(mark, buf, sign, fraction, exponent, fraction_exp, ulp_half_error, result);
}
```