user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<split>:
  endbr64
  push   %rbx
  mov    %rsi,%r9
  movzbl (%rcx),%esi
  mov    %edx,%r8d
  mov    %rdi,%rax
  movzbl (%rdi),%edx
  test   %sil,%sil
  je     L393
  xor    %r10d,%r10d
  test   %dl,%dl
  je     L366
  movzbl 0x1(%rcx),%edi
  test   %dil,%dil
  jne    L115
  mov    %r8d,%ecx
  mov    %rax,(%r9)
  lea    0x8(%r9),%rdi
  sub    $0x1,%ecx
  jne    L232
  jmp    L25
  xchg   %ax,%ax
L183:
  test   %dl,%dl
  je     L458
L232:
  movzbl (%rax),%edx
  add    $0x1,%rax
  cmp    %dl,%sil
  jne    L183
  add    $0x8,%rdi
  movb   $0x0,-0x1(%rax)
  mov    %rax,-0x8(%rdi)
  sub    $0x1,%ecx
  jne    L232
L25:
  mov    %r8d,%r10d
  nopl   0x0(%rax,%rax,1)
L236:
  movzbl (%rax),%edx
  add    $0x1,%rax
  cmp    %dl,%sil
  je     L480
  test   %dl,%dl
  jne    L236
L366:
  mov    %r10d,%eax
  pop    %rbx
  ret
  nopl   0x0(%rax)
L456:
  mov    %rcx,%rax
L393:
  movzbl (%rax),%edx
  lea    0x1(%rax),%rcx
  cmp    $0x9,%dl
  je     L456
  cmp    $0x20,%dl
  je     L456
  xor    %r10d,%r10d
  test   %dl,%dl
  je     L366
  mov    $0x9,%edi
  mov    $0x1,%ebx
  mov    $0x20,%esi
L454:
  mov    %r8d,%r11d
L464:
  add    $0x8,%r9
  mov    %r11d,%r10d
  mov    %rax,%rcx
  sub    $0x1,%r11d
  mov    %rax,-0x8(%r9)
  jmp    L198
  nopl   0x0(%rax)
L38:
  cmp    %sil,%dl
  je     L118
  test   %dl,%dl
  je     L165
L198:
  movzbl (%rcx),%edx
  add    $0x1,%rcx
  cmp    %dil,%dl
  jne    L38
L118:
  test   %r11d,%r11d
  je     L235
  movb   $0x0,-0x1(%rcx)
  mov    %rcx,%rax
L380:
  movzbl (%rax),%edx
  lea    0x1(%rax),%rcx
  cmp    %sil,%dl
  je     L149
  cmp    %dil,%dl
  jne    L464
L149:
  mov    %rcx,%rax
  jmp    L380
  nopl   0x0(%rax,%rax,1)
L458:
  sub    %ecx,%r8d
  pop    %rbx
  mov    %r8d,%r10d
  mov    %r10d,%eax
  ret
  nopl   0x0(%rax,%rax,1)
L165:
  test   %ebx,%ebx
  je     L306
  cmpb   $0x0,(%rax)
  cmove  %r10d,%r11d
L306:
  sub    %r11d,%r8d
  pop    %rbx
  mov    %r8d,%r10d
  mov    %r10d,%eax
  ret
L115:
  cmpb   $0x0,0x2(%rcx)
  je     L152
L418:
  cmp    %r8d,%r10d
  jge    L431
  mov    %rax,(%r9)
  add    $0x8,%r9
L431:
  movzbl (%rax),%edi
  add    $0x1,%r10d
  lea    0x1(%rax),%rsi
  test   %dil,%dil
  je     L366
  nopl   0x0(%rax,%rax,1)
L428:
  mov    %rcx,%rax
L67:
  movzbl (%rax),%edx
  add    $0x1,%rax
  test   %dl,%dl
  je     L451
  cmp    %dil,%dl
  jne    L67
  cmp    %r10d,%r8d
  jle    L10
  movb   $0x0,-0x1(%rsi)
  nopl   0x0(%rax)
L10:
  mov    %rsi,%rax
  movzbl (%rsi),%r11d
  add    $0x1,%rsi
  mov    %rcx,%rdx
L0:
  movzbl (%rdx),%edi
  add    $0x1,%rdx
  test   %dil,%dil
  je     L418
  cmp    %dil,%r11b
  je     L10
  jmp    L0
  nopl   0x0(%rax)
L451:
  movzbl (%rsi),%edi
  add    $0x1,%rsi
  test   %dil,%dil
  jne    L428
  mov    %r10d,%eax
  pop    %rbx
  ret
  nopl   0x0(%rax)
L480:
  add    $0x1,%r10d
  jmp    L236
L235:
  mov    %r8d,%r10d
  test   %dl,%dl
  je     L444
L281:
  movzbl (%rcx),%eax
  lea    0x1(%rcx),%rdx
  cmp    %dil,%al
  je     L427
  cmp    %sil,%al
  je     L427
  add    $0x1,%r10d
  mov    %rdx,%rcx
  test   %al,%al
  je     L444
L19:
  cmp    %sil,%al
  je     L281
  cmp    %dil,%al
  je     L281
  movzbl (%rdx),%eax
  add    $0x1,%rdx
  mov    %rdx,%rcx
  test   %al,%al
  jne    L19
L444:
  sub    $0x1,%rcx
  test   %ebx,%ebx
  je     L366
L40:
  movzbl -0x1(%rcx),%eax
  lea    -0x1(%rcx),%rdx
  cmp    %dil,%al
  je     L325
  cmp    %sil,%al
  je     L325
  cmpb   $0x0,(%rcx)
  je     L366
  add    $0x1,%r8d
  cmp    %r10d,%r8d
  jne    L7
  movb   $0x0,(%rcx)
L7:
  sub    $0x1,%r10d
  jmp    L366
L427:
  mov    %rdx,%rcx
  jmp    L281
L325:
  mov    %rdx,%rcx
  jmp    L40
L152:
  xor    %ebx,%ebx
  jmp    L454
```

assistant: ```c
int split(string, fields, nfields, sep)
char *string;
char *fields[];
int nfields;
char *sep;
{
  register char *p = string;
  register char c;
  register char sepc = sep[0];
  register char sepc2;
  register int fn;
  register char **fp = fields;
  register char *sepp;
  register int trimtrail;
  if (sepc == '\0') {
    while ((c = *p++) == ' ' || c == '\t')
      continue;
    p--;
    trimtrail = 1;
    sep = " \t";
    sepc = ' ';
  } else
    trimtrail = 0;
  sepc2 = sep[1];
  if (*p == '\0')
    return (0);
  if (sepc2 == '\0') {
    fn = nfields;
    for (;;) {
      *fp++ = p;
      fn--;
      if (fn == 0)
        break;
      while ((c = *p++) != sepc)
        if (c == '\0')
          return (nfields - fn);
      *(p - 1) = '\0';
    }
    fn = nfields;
    for (;;) {
      while ((c = *p++) != sepc)
        if (c == '\0')
          return (fn);
      fn++;
    }
  }
  if (sep[2] == '\0') {
    fn = nfields;
    for (;;) {
      *fp++ = p;
      fn--;
      while ((c = *p++) != sepc && c != sepc2)
        if (c == '\0') {
          if (trimtrail && **(fp - 1) == '\0')
            fn++;
          return (nfields - fn);
        }
      if (fn == 0)
        break;
      *(p - 1) = '\0';
      while ((c = *p++) == sepc || c == sepc2)
        continue;
      p--;
    }
    fn = nfields;
    while (c != '\0') {
      while ((c = *p++) == sepc || c == sepc2)
        continue;
      p--;
      fn++;
      while ((c = *p++) != '\0' && c != sepc && c != sepc2)
        continue;
    }
    if (trimtrail) {
      p--;
      while ((c = *--p) == sepc || c == sepc2)
        continue;
      p++;
      if (*p != '\0') {
        if (fn == nfields + 1)
          *p = '\0';
        fn--;
      }
    }
    return (fn);
  }
  fn = 0;
  for (;;) {
    if (fn < nfields)
      *fp++ = p;
    fn++;
    for (;;) {
      c = *p++;
      if (c == '\0')
        return (fn);
      sepp = sep;
      while ((sepc = *sepp++) != '\0' && sepc != c)
        continue;
      if (sepc != '\0')
        break;
    }
    if (fn < nfields)
      *(p - 1) = '\0';
    for (;;) {
      c = *p++;
      sepp = sep;
      while ((sepc = *sepp++) != '\0' && sepc != c)
        continue;
      if (sepc == '\0')
        break;
    }
    p--;
  }
}
```