user: What would the C source look like for the assembly code provided here:

```asm
<mark>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x38,%rsp
  call   <isPtr@plt>
  test   %rax,%rax
  je     L274
  mov    %rax,%rdi
  mov    %rax,%rbx
  call   <blockAllocated@plt>
  test   %rax,%rax
  jne    L240
L274:
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L240:
  mov    %rbx,%rdi
  call   <blockMarked@plt>
  test   %eax,%eax
  je     L300
L193:
  mov    %rbx,%rdi
  call   <length@plt>
  test   %eax,%eax
  lea    0x3(%rax),%edx
  cmovns %eax,%edx
  sar    $0x2,%edx
  cmp    $0x7,%eax
  jle    L274
  mov    %edx,(%rsp)
  add    $0x4,%rbx
  mov    $0x1,%r13d
L120:
  mov    %rbx,%rdi
  call   <isPtr@plt>
  mov    %rax,%rbp
  test   %rax,%rax
  je     L324
  mov    %rax,%rdi
  call   <blockAllocated@plt>
  test   %rax,%rax
  jne    L124
L324:
  add    $0x1,%r13d
  add    $0x4,%rbx
  cmp    %r13d,(%rsp)
  jg     L120
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nop
L124:
  mov    %rbp,%rdi
  call   <blockMarked@plt>
  test   %eax,%eax
  je     L169
L53:
  mov    %rbp,%rdi
  call   <length@plt>
  test   %eax,%eax
  lea    0x3(%rax),%edx
  cmovns %eax,%edx
  sar    $0x2,%edx
  mov    %edx,0x4(%rsp)
  cmp    $0x7,%eax
  jle    L324
  mov    %rbx,0x8(%rsp)
  add    $0x4,%rbp
  mov    $0x1,%r15d
  mov    %r13d,0x14(%rsp)
L151:
  mov    %rbp,%rdi
  call   <isPtr@plt>
  mov    %rax,%rbx
  test   %rax,%rax
  je     L213
  mov    %rax,%rdi
  call   <blockAllocated@plt>
  test   %rax,%rax
  jne    L36
L213:
  add    $0x1,%r15d
  add    $0x4,%rbp
  cmp    %r15d,0x4(%rsp)
  jg     L151
  mov    0x8(%rsp),%rbx
  mov    0x14(%rsp),%r13d
  jmp    L324
  nopl   0x0(%rax,%rax,1)
L36:
  mov    %rbx,%rdi
  call   <blockMarked@plt>
  test   %eax,%eax
  je     L293
L24:
  mov    %rbx,%rdi
  call   <length@plt>
  test   %eax,%eax
  lea    0x3(%rax),%edx
  cmovns %eax,%edx
  sar    $0x2,%edx
  mov    %edx,0x10(%rsp)
  cmp    $0x7,%eax
  jle    L213
  mov    %r15d,0x20(%rsp)
  add    $0x4,%rbx
  mov    $0x1,%r13d
  mov    %rbp,0x18(%rsp)
L255:
  mov    %rbx,%rdi
  call   <isPtr@plt>
  mov    %rax,%r12
  test   %rax,%rax
  je     L264
  mov    %rax,%rdi
  call   <blockAllocated@plt>
  test   %rax,%rax
  jne    L248
L264:
  add    $0x1,%r13d
  add    $0x4,%rbx
  cmp    %r13d,0x10(%rsp)
  jg     L255
  mov    0x20(%rsp),%r15d
  mov    0x18(%rsp),%rbp
  jmp    L213
  nopl   0x0(%rax,%rax,1)
L300:
  mov    %rbx,%rdi
  call   <markBlock@plt>
  jmp    L193
  nopl   (%rax)
L293:
  mov    %rbx,%rdi
  call   <markBlock@plt>
  jmp    L24
  nopl   (%rax)
L248:
  mov    %r12,%rdi
  call   <blockMarked@plt>
  test   %eax,%eax
  je     L338
L216:
  mov    %r12,%rdi
  call   <length@plt>
  test   %eax,%eax
  lea    0x3(%rax),%edx
  cmovns %eax,%edx
  sar    $0x2,%edx
  mov    %edx,%r15d
  cmp    $0x7,%eax
  jle    L264
  mov    %r13d,0x24(%rsp)
  add    $0x4,%r12
  mov    $0x1,%r14d
  mov    %rbx,0x28(%rsp)
L180:
  mov    %r12,%rdi
  call   <isPtr@plt>
  mov    %rax,%r13
  test   %rax,%rax
  je     L284
  mov    %rax,%rdi
  call   <blockAllocated@plt>
  test   %rax,%rax
  jne    L190
L284:
  add    $0x1,%r14d
  add    $0x4,%r12
  cmp    %r14d,%r15d
  jg     L180
  mov    0x24(%rsp),%r13d
  mov    0x28(%rsp),%rbx
  jmp    L264
  nopl   0x0(%rax,%rax,1)
L169:
  mov    %rbp,%rdi
  call   <markBlock@plt>
  jmp    L53
  nopl   (%rax)
L190:
  mov    %r13,%rdi
  call   <blockMarked@plt>
  test   %eax,%eax
  je     L218
L262:
  mov    %r13,%rdi
  call   <length@plt>
  test   %eax,%eax
  lea    0x3(%rax),%ebp
  cmovns %eax,%ebp
  sar    $0x2,%ebp
  cmp    $0x7,%eax
  jle    L284
  add    $0x4,%r13
  mov    $0x1,%ebx
L15:
  mov    %r13,%rdi
  add    $0x1,%ebx
  add    $0x4,%r13
  call   <mark>
  cmp    %ebx,%ebp
  jg     L15
  jmp    L284
  nopw   0x0(%rax,%rax,1)
L338:
  mov    %r12,%rdi
  call   <markBlock@plt>
  jmp    L216
L218:
  mov    %r13,%rdi
  call   <markBlock@plt>
  jmp    L262
```

assistant: ```c
void mark(int *p) {
  int i = 0, size;
  int *ptr;
  ptr = isPtr(p);
  if (ptr != NULL && blockAllocated(ptr)) {
    if (!blockMarked(ptr)) {
      markBlock(ptr);
    }
    size = length(ptr) / 4;
    while (++i < size) {
      mark(ptr + i);
    }
  }
}
```