user: 请从给定的汇编指令推导出C源代码：

```asm
<convert>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0xc8,%rsp
  mov    %rdi,-0x88(%rbp)
  mov    %esi,-0x8c(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  mov    %rsp,%rax
  mov    %rax,-0xe8(%rbp)
  mov    -0x88(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  mov    %eax,-0x70(%rbp)
  cmpl   $0x1,-0x8c(%rbp)
  jle    L137
  mov    -0x8c(%rbp),%eax
  cmp    -0x70(%rbp),%eax
  jl     L72
L137:
  mov    -0x88(%rbp),%rax
  jmp    L76
L72:
  mov    -0x8c(%rbp),%esi
  movslq %esi,%rax
  sub    $0x1,%rax
  mov    %rax,-0x68(%rbp)
  movslq %esi,%rax
  mov    %rax,-0xc0(%rbp)
  movq   $0x0,-0xb8(%rbp)
  movslq %esi,%rax
  mov    %rax,-0xd0(%rbp)
  movq   $0x0,-0xc8(%rbp)
  movslq %esi,%rax
  lea    0x0(,%rax,4),%rdx
  mov    $0x10,%eax
  sub    $0x1,%rax
  add    %rdx,%rax
  mov    $0x10,%ebx
  mov    $0x0,%edx
  div    %rbx
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L70:
  cmp    %rdx,%rsp
  je     L15
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L70
L15:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L132
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L132:
  mov    %rsp,%rax
  add    $0x3,%rax
  shr    $0x2,%rax
  shl    $0x2,%rax
  mov    %rax,-0x60(%rbp)
  movslq %esi,%rax
  shl    $0x2,%eax
  mov    %eax,%edx
  mov    -0x60(%rbp),%rax
  mov    $0x0,%esi
  mov    %rax,%rdi
  call   <memset@plt>
  mov    -0x70(%rbp),%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %edx,%eax
  sar    %eax
  lea    0x1(%rax),%ecx
  mov    -0x8c(%rbp),%esi
  movslq %ecx,%rax
  sub    $0x1,%rax
  mov    %rax,-0x58(%rbp)
  movslq %ecx,%rax
  mov    %rax,-0xe0(%rbp)
  movq   $0x0,-0xd8(%rbp)
  movslq %ecx,%rbx
  movslq %esi,%rax
  sub    $0x1,%rax
  mov    %rax,-0x50(%rbp)
  movslq %ecx,%rax
  mov    %rax,-0xa0(%rbp)
  movq   $0x0,-0x98(%rbp)
  movslq %esi,%rax
  mov    %rax,-0xb0(%rbp)
  movq   $0x0,-0xa8(%rbp)
  mov    -0xa0(%rbp),%r8
  mov    -0x98(%rbp),%r9
  mov    %r9,%rdx
  mov    -0xb0(%rbp),%r10
  mov    -0xa8(%rbp),%r11
  imul   %r10,%rdx
  mov    %r11,%rax
  imul   %r8,%rax
  lea    (%rdx,%rax,1),%rdi
  mov    %r8,%rax
  mul    %r10
  add    %rdx,%rdi
  mov    %rdi,%rdx
  movslq %ecx,%rax
  mov    %rax,%r14
  mov    $0x0,%r15d
  movslq %esi,%rax
  mov    %rax,%r12
  mov    $0x0,%r13d
  mov    %r15,%rdx
  imul   %r12,%rdx
  mov    %r13,%rax
  imul   %r14,%rax
  lea    (%rdx,%rax,1),%rdi
  mov    %r14,%rax
  mul    %r12
  add    %rdx,%rdi
  mov    %rdi,%rdx
  movslq %ecx,%rdx
  movslq %esi,%rax
  imul   %rdx,%rax
  mov    $0x10,%edx
  sub    $0x1,%rdx
  add    %rdx,%rax
  mov    $0x10,%edi
  mov    $0x0,%edx
  div    %rdi
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L114:
  cmp    %rdx,%rsp
  je     L138
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L114
L138:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L122
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L122:
  mov    %rsp,%rax
  add    $0x0,%rax
  mov    %rax,-0x48(%rbp)
  movl   $0x0,-0x80(%rbp)
  movl   $0x1,-0x7c(%rbp)
  movl   $0x0,-0x78(%rbp)
  movl   $0x0,-0x6c(%rbp)
  movl   $0x0,-0x78(%rbp)
  jmp    L2
L107:
  mov    -0x78(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x88(%rbp),%rax
  lea    (%rdx,%rax,1),%rdi
  mov    -0x60(%rbp),%rax
  mov    -0x80(%rbp),%edx
  movslq %edx,%rdx
  mov    (%rax,%rdx,4),%eax
  lea    0x1(%rax),%esi
  mov    -0x60(%rbp),%rdx
  mov    -0x80(%rbp),%ecx
  movslq %ecx,%rcx
  mov    %esi,(%rdx,%rcx,4)
  movzbl (%rdi),%edx
  mov    -0x48(%rbp),%rsi
  movslq %eax,%rcx
  mov    -0x80(%rbp),%eax
  cltq
  imul   %rbx,%rax
  add    %rsi,%rcx
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    -0x8c(%rbp),%eax
  sub    $0x1,%eax
  cmp    %eax,-0x80(%rbp)
  jne    L19
  movl   $0xffffffff,-0x7c(%rbp)
L19:
  cmpl   $0x0,-0x80(%rbp)
  jne    L53
  movl   $0x1,-0x7c(%rbp)
L53:
  mov    -0x7c(%rbp),%eax
  add    %eax,-0x80(%rbp)
  addl   $0x1,-0x78(%rbp)
L2:
  mov    -0x78(%rbp),%eax
  cmp    -0x70(%rbp),%eax
  jl     L107
  mov    -0x70(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x40(%rbp)
  movl   $0x0,-0x74(%rbp)
  movl   $0x0,-0x78(%rbp)
  jmp    L28
L58:
  mov    -0x60(%rbp),%rax
  mov    -0x78(%rbp),%edx
  movslq %edx,%rdx
  mov    (%rax,%rdx,4),%eax
  mov    -0x78(%rbp),%edx
  movslq %edx,%rdx
  mov    %rdx,%rcx
  imul   %rbx,%rcx
  mov    -0x48(%rbp),%rdx
  lea    (%rcx,%rdx,1),%rsi
  mov    -0x74(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x40(%rbp),%rdx
  add    %rdx,%rcx
  mov    %eax,%edx
  mov    %rcx,%rdi
  call   <memcpy@plt>
  mov    -0x60(%rbp),%rax
  mov    -0x78(%rbp),%edx
  movslq %edx,%rdx
  mov    (%rax,%rdx,4),%eax
  add    %eax,-0x74(%rbp)
  addl   $0x1,-0x78(%rbp)
L28:
  mov    -0x78(%rbp),%eax
  cmp    -0x8c(%rbp),%eax
  jl     L58
  mov    -0x70(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  mov    -0x40(%rbp),%rax
L76:
  mov    -0xe8(%rbp),%rsp
  mov    -0x38(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L18
  call   <__stack_chk_fail@plt>
L18:
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
```

assistant: ```c
char *convert(char *s, int rows) {
  int n = strlen(s);
  if (rows <= 1 || rows >= n)
    return s;
  int count[rows];
  memset(count, 0, sizeof(count));
  char rows_result[rows][n / 2 + 1];
  int step = 0;
  int direct = 1;
  int i = 0, j = 0;
  for (i = 0; i < n; i++) {
    rows_result[step][count[step]++] = s[i];
    if (step == rows - 1)
      direct = -1;
    if (step == 0)
      direct = 1;
    step += direct;
  }
  char *result = malloc(n + 1);
  int cusor = 0;
  for (i = 0; i < rows; i++) {
    memcpy(result + cusor, rows_result[i], count[i]);
    cusor += count[i];
  }
  result[n] = '\0';
  return result;
}
```