user: Please show me the C implementation that matches the assembly code listed below:

```asm
<printgraph>:
  endbr64
  push   %r15
  movsbl %dil,%edx
  push   %r14
  lea    -0x40(%rdx),%eax
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  mov    %edx,0xc(%rsp)
  mov    %eax,0x8(%rsp)
  test   %eax,%eax
  jle    L219
  lea    -0x1(%rax,%rax,1),%ebp
  lea    0x3f(%rax,%rax,1),%eax
  xor    %ebx,%ebx
  mov    %al,0x7(%rsp)
  lea    -0x82(%rdx,%rdx,1),%r14d
  mov    %r14d,%r13d
  nopw   0x0(%rax,%rax,1)
L77:
  test   %ebx,%ebx
  lea    0x41(%rbx),%eax
  sete   %r12b
  mov    %eax,(%rsp)
  xor    %r15d,%r15d
  jmp    L146
  nopl   0x0(%rax)
L142:
  cmp    %r15d,%ebx
  jge    L125
  cmp    %r14d,%r15d
  jge    L161
  mov    (%rsp),%edi
  call   <putchar@plt>
L94:
  add    $0x1,%r15d
  cmp    %ebp,%r15d
  je     L130
L146:
  test   %r15d,%r15d
  je     L244
  test   %r12b,%r12b
  jne    L244
  cmp    %r15d,%r13d
  jne    L142
L244:
  mov    $0x41,%edi
  add    $0x1,%r15d
  call   <putchar@plt>
  cmp    %ebp,%r15d
  jne    L146
L130:
  mov    $0xa,%edi
  add    $0x1,%ebx
  sub    $0x1,%r14d
  call   <putchar@plt>
  cmp    0x8(%rsp),%ebx
  jne    L77
L219:
  mov    0xc(%rsp),%eax
  mov    %eax,%ebp
  sub    $0x42,%ebp
  js     L68
  mov    0x8(%rsp),%ecx
  lea    -0x82(%rax,%rax,1),%r13d
  lea    -0x40(%rax),%r14d
  mov    %ecx,%esi
  lea    -0x1(%rcx,%rcx,1),%ebx
  lea    0x3f(%rsi,%rsi,1),%esi
  mov    %sil,0x7(%rsp)
  nopw   0x0(%rax,%rax,1)
L154:
  test   %ebp,%ebp
  lea    0x41(%rbp),%eax
  sete   %r12b
  mov    %al,(%rsp)
  xor    %r15d,%r15d
  test   %ebx,%ebx
  jg     L19
  jmp    L214
  nopl   (%rax)
L137:
  cmp    %ebp,%r15d
  jle    L52
  cmp    %r14d,%r15d
  jge    L165
  movzbl (%rsp),%edi
  call   <putchar@plt>
L109:
  add    $0x1,%r15d
  cmp    %ebx,%r15d
  je     L214
L19:
  test   %r15d,%r15d
  je     L74
  test   %r12b,%r12b
  jne    L74
  cmp    %r15d,%r13d
  jne    L137
L74:
  mov    $0x41,%edi
  add    $0x1,%r15d
  call   <putchar@plt>
  cmp    %ebx,%r15d
  jne    L19
L214:
  mov    $0xa,%edi
  sub    $0x1,%ebp
  add    $0x1,%r14d
  call   <putchar@plt>
  cmp    $0xffffffff,%ebp
  jne    L154
L68:
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L161:
  movzbl 0x7(%rsp),%edi
  sub    %r15d,%edi
  movsbl %dil,%edi
  call   <putchar@plt>
  jmp    L94
  xchg   %ax,%ax
L125:
  lea    0x41(%r15),%edi
  call   <putchar@plt>
  jmp    L94
  xchg   %ax,%ax
L165:
  movzbl 0x7(%rsp),%edi
  sub    %r15d,%edi
  movsbl %dil,%edi
  call   <putchar@plt>
  jmp    L109
  cs nopw 0x0(%rax,%rax,1)
L52:
  lea    0x41(%r15),%edi
  call   <putchar@plt>
  jmp    L109
```

assistant: ```c
void printgraph(char ch) {
  int i, j;
  int n = ch - 'A' + 1;
  for (i = 0; i < n; i++) {
    for (j = 0; j < 2 * n - 1; j++) {
      if (i == 0 || j == 0 || j == 2 * n - 2)
        putchar('A');
      else {
        if (j <= i)
          putchar('A' + j);
        else if (j > i && j < 2 * n - 2 - i)
          putchar('A' + i);
        else
          putchar('A' + 2 * n - 2 - j);
      }
    }
    putchar('\n');
  }
  for (i = n - 2; i >= 0; i--) {
    for (j = 0; j < 2 * n - 1; j++) {
      if (i == 0 || j == 0 || j == 2 * n - 2)
        putchar('A');
      else {
        if (j <= i)
          putchar('A' + j);
        else if (j > i && j < 2 * n - 2 - i)
          putchar('A' + i);
        else
          putchar('A' + 2 * n - 2 - j);
      }
    }
    putchar('\n');
  }
}
```