user: 请从给定的汇编指令推导出C源代码：

```asm
<qsc>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,0x48(%rsp)
  mov    %esi,0x50(%rsp)
L289:
  mov    0x50(%rsp),%ebx
  mov    0x48(%rsp),%r11
  mov    $0x1,%r9d
  xor    %r8d,%r8d
  mov    %ebx,%eax
  mov    %ebx,%edx
  sar    %eax
  cltq
  movzbl (%r11,%rax,1),%ecx
  movslq %ebx,%rax
L296:
  movzbl (%r11,%r8,1),%ebp
  lea    (%r11,%rax,1),%rdi
  mov    %r8d,%ebx
  movzbl (%rdi),%esi
  cmp    %cl,%bpl
  jl     L767
  cmp    %sil,%cl
  jge    L114
  lea    -0x1(%r11,%rax,1),%rax
  lea    -0x1(%rdx),%r10d
  sub    %eax,%r10d
L434:
  lea    (%r10,%rax,1),%edx
  mov    %rax,%rdi
  movzbl (%rax),%esi
  sub    $0x1,%rax
  cmp    %cl,%sil
  jg     L434
L114:
  cmp    %r8d,%edx
  jge    L47
  mov    %ebx,0x54(%rsp)
  mov    %edx,0xc(%rsp)
L807:
  mov    0xc(%rsp),%eax
  test   %eax,%eax
  jg     L23
L717:
  mov    0x50(%rsp),%eax
  mov    0x54(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L96
  sub    %ebx,%eax
  mov    %eax,0x50(%rsp)
  movslq %ebx,%rax
  add    %rax,0x48(%rsp)
  jmp    L289
L47:
  sub    $0x1,%edx
  mov    %sil,(%r11,%r8,1)
  mov    %bpl,(%rdi)
  cmp    %edx,%r9d
  jg     L541
  movslq %edx,%rax
L767:
  add    $0x1,%r8
  add    $0x1,%r9d
  jmp    L296
L96:
  add    $0x78,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L23:
  mov    0x48(%rsp),%rax
  mov    %rax,0x10(%rsp)
L321:
  mov    0xc(%rsp),%ebx
  mov    0x10(%rsp),%r10
  mov    $0x1,%r8d
  xor    %edi,%edi
  mov    %ebx,%eax
  mov    %ebx,%edx
  sar    %eax
  cltq
  movzbl (%r10,%rax,1),%esi
  movslq %ebx,%rax
L848:
  movzbl (%r10,%rdi,1),%r11d
  lea    (%r10,%rax,1),%r9
  mov    %edi,%ebx
  movzbl (%r9),%ecx
  cmp    %r11b,%sil
  jg     L372
  cmp    %cl,%sil
  jge    L252
  lea    -0x1(%r10,%rax,1),%rax
  nopl   0x0(%rax)
L337:
  mov    %rax,%r9
  movzbl (%rax),%ecx
  sub    $0x1,%rax
  sub    $0x1,%edx
  cmp    %cl,%sil
  jl     L337
L252:
  cmp    %edi,%edx
  jge    L606
L566:
  mov    %ebx,0x58(%rsp)
  mov    %edx,0x20(%rsp)
  test   %edx,%edx
  jg     L622
L344:
  mov    0xc(%rsp),%eax
  mov    0x58(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L717
  sub    %ebx,%eax
  mov    %eax,0xc(%rsp)
  movslq %ebx,%rax
  add    %rax,0x10(%rsp)
  jmp    L321
L606:
  sub    $0x1,%edx
  mov    %cl,(%r10,%rdi,1)
  mov    %r8d,%ebx
  mov    %r11b,(%r9)
  cmp    %edx,%r8d
  jg     L566
  movslq %edx,%rax
L372:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L848
L622:
  mov    0x10(%rsp),%rax
  mov    %rax,0x18(%rsp)
L524:
  mov    0x20(%rsp),%ebx
  mov    0x18(%rsp),%r10
  mov    $0x1,%r8d
  xor    %edi,%edi
  mov    %ebx,%eax
  mov    %ebx,%edx
  sar    %eax
  cltq
  movzbl (%r10,%rax,1),%esi
  movslq %ebx,%rax
L658:
  movzbl (%r10,%rdi,1),%r11d
  lea    (%r10,%rax,1),%r9
  mov    %edi,%ebx
  movzbl (%r9),%ecx
  cmp    %r11b,%sil
  jg     L577
  cmp    %cl,%sil
  jge    L749
  lea    -0x1(%r10,%rax,1),%rax
  nopl   0x0(%rax,%rax,1)
L20:
  mov    %rax,%r9
  movzbl (%rax),%ecx
  sub    $0x1,%rax
  sub    $0x1,%edx
  cmp    %cl,%sil
  jl     L20
L749:
  cmp    %edi,%edx
  jge    L707
L678:
  mov    %ebx,0x5c(%rsp)
  mov    %edx,0x24(%rsp)
  test   %edx,%edx
  jg     L689
L580:
  mov    0x20(%rsp),%eax
  mov    0x5c(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L344
  sub    %ebx,%eax
  mov    %eax,0x20(%rsp)
  movslq %ebx,%rax
  add    %rax,0x18(%rsp)
  jmp    L524
L707:
  sub    $0x1,%edx
  mov    %cl,(%r10,%rdi,1)
  mov    %r8d,%ebx
  mov    %r11b,(%r9)
  cmp    %edx,%r8d
  jg     L678
  movslq %edx,%rax
L577:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L658
L689:
  mov    0x18(%rsp),%rax
  mov    %rax,0x28(%rsp)
L713:
  mov    0x24(%rsp),%ebx
  mov    0x28(%rsp),%r10
  mov    $0x1,%r8d
  xor    %edi,%edi
  mov    %ebx,%eax
  mov    %ebx,%edx
  sar    %eax
  cltq
  movzbl (%r10,%rax,1),%esi
  movslq %ebx,%rax
L350:
  movzbl (%r10,%rdi,1),%r11d
  lea    (%r10,%rax,1),%r9
  mov    %edi,%ebx
  movzbl (%r9),%ecx
  cmp    %r11b,%sil
  jg     L744
  cmp    %cl,%sil
  jge    L700
  lea    -0x1(%r10,%rax,1),%rax
L70:
  mov    %rax,%r9
  movzbl (%rax),%ecx
  sub    $0x1,%rax
  sub    $0x1,%edx
  cmp    %cl,%sil
  jl     L70
L700:
  cmp    %edi,%edx
  jge    L146
L147:
  mov    %ebx,0x60(%rsp)
  mov    %edx,0x38(%rsp)
  test   %edx,%edx
  jg     L480
L647:
  mov    0x24(%rsp),%eax
  mov    0x60(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L580
  sub    %ebx,%eax
  mov    %eax,0x24(%rsp)
  movslq %ebx,%rax
  add    %rax,0x28(%rsp)
  jmp    L713
L146:
  sub    $0x1,%edx
  mov    %cl,(%r10,%rdi,1)
  mov    %r8d,%ebx
  mov    %r11b,(%r9)
  cmp    %edx,%r8d
  jg     L147
  movslq %edx,%rax
L744:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L350
L480:
  mov    0x28(%rsp),%rax
  mov    %rax,0x30(%rsp)
L471:
  mov    0x38(%rsp),%ebx
  mov    0x30(%rsp),%r10
  mov    $0x1,%r8d
  xor    %edi,%edi
  mov    %ebx,%eax
  mov    %ebx,%edx
  sar    %eax
  cltq
  movzbl (%r10,%rax,1),%esi
  movslq %ebx,%rax
  nopw   0x0(%rax,%rax,1)
L775:
  movzbl (%r10,%rdi,1),%r11d
  lea    (%r10,%rax,1),%r9
  mov    %edi,%ebx
  movzbl (%r9),%ecx
  cmp    %r11b,%sil
  jg     L573
  cmp    %cl,%sil
  jge    L391
  lea    -0x1(%r10,%rax,1),%rax
  cs nopw 0x0(%rax,%rax,1)
L615:
  mov    %rax,%r9
  movzbl (%rax),%ecx
  sub    $0x1,%rax
  sub    $0x1,%edx
  cmp    %cl,%sil
  jl     L615
L391:
  cmp    %edi,%edx
  jge    L42
L60:
  mov    %ebx,0x64(%rsp)
  mov    %edx,0x3c(%rsp)
  test   %edx,%edx
  jg     L269
L811:
  mov    0x38(%rsp),%eax
  mov    0x64(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L647
  sub    %ebx,%eax
  mov    %eax,0x38(%rsp)
  movslq %ebx,%rax
  add    %rax,0x30(%rsp)
  jmp    L471
L42:
  sub    $0x1,%edx
  mov    %cl,(%r10,%rdi,1)
  mov    %r8d,%ebx
  mov    %r11b,(%r9)
  cmp    %edx,%r8d
  jg     L60
  movslq %edx,%rax
L573:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L775
L269:
  mov    0x30(%rsp),%rax
  mov    %rax,0x40(%rsp)
L89:
  mov    0x3c(%rsp),%ebx
  mov    0x40(%rsp),%r9
  mov    $0x1,%r8d
  xor    %edi,%edi
  mov    %ebx,%eax
  mov    %ebx,%r15d
  sar    %eax
  cltq
  movzbl (%r9,%rax,1),%esi
  movslq %ebx,%rax
  nopl   0x0(%rax,%rax,1)
L473:
  movzbl (%r9,%rdi,1),%r10d
  lea    (%r9,%rax,1),%rcx
  mov    %edi,%r11d
  movzbl (%rcx),%edx
  cmp    %r10b,%sil
  jg     L582
  cmp    %dl,%sil
  jge    L651
  lea    -0x1(%r9,%rax,1),%rax
  cs nopw 0x0(%rax,%rax,1)
L319:
  mov    %rax,%rcx
  movzbl (%rax),%edx
  sub    $0x1,%rax
  sub    $0x1,%r15d
  cmp    %dl,%sil
  jl     L319
L651:
  cmp    %edi,%r15d
  jge    L358
L504:
  mov    %r11d,0x68(%rsp)
  test   %r15d,%r15d
  jg     L428
L19:
  mov    0x3c(%rsp),%eax
  mov    0x68(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L811
  sub    %ebx,%eax
  mov    %eax,0x3c(%rsp)
  movslq %ebx,%rax
  add    %rax,0x40(%rsp)
  jmp    L89
L358:
  sub    $0x1,%r15d
  mov    %dl,(%r9,%rdi,1)
  mov    %r8d,%r11d
  mov    %r10b,(%rcx)
  cmp    %r15d,%r8d
  jg     L504
  movslq %r15d,%rax
L582:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L473
L428:
  mov    %r15d,0x4(%rsp)
  mov    0x40(%rsp),%r9
L777:
  mov    0x4(%rsp),%ebx
  mov    $0x1,%r8d
  xor    %edi,%edi
  mov    %ebx,%eax
  mov    %ebx,%ebp
  sar    %eax
  cltq
  movzbl (%r9,%rax,1),%esi
  movslq %ebx,%rax
  xchg   %ax,%ax
L272:
  movzbl (%r9,%rdi,1),%r10d
  lea    (%r9,%rax,1),%rcx
  mov    %edi,%r11d
  movzbl (%rcx),%edx
  cmp    %r10b,%sil
  jg     L200
  cmp    %dl,%sil
  jge    L742
  lea    -0x1(%r9,%rax,1),%rax
  xchg   %ax,%ax
L141:
  mov    %rax,%rcx
  movzbl (%rax),%edx
  sub    $0x1,%rax
  sub    $0x1,%ebp
  cmp    %dl,%sil
  jl     L141
L742:
  cmp    %edi,%ebp
  jge    L122
L506:
  mov    %r11d,0x8(%rsp)
  test   %ebp,%ebp
  jg     L144
L329:
  mov    0x4(%rsp),%eax
  mov    0x8(%rsp),%ebx
  cmp    %ebx,%eax
  jle    L19
  sub    %ebx,%eax
  mov    %eax,0x4(%rsp)
  movslq %ebx,%rax
  add    %rax,%r9
  jmp    L777
  nopl   (%rax)
L122:
  sub    $0x1,%ebp
  mov    %dl,(%r9,%rdi,1)
  mov    %r8d,%r11d
  mov    %r10b,(%rcx)
  cmp    %ebp,%r8d
  jg     L506
  movslq %ebp,%rax
L200:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L272
L144:
  mov    %r9,%r14
  mov    %r9,%r15
L616:
  mov    %ebp,%eax
  mov    %ebp,%ebx
  mov    $0x1,%r8d
  xor    %edi,%edi
  sar    %eax
  cltq
  movzbl (%r14,%rax,1),%esi
  movslq %ebp,%rax
  nopl   (%rax)
L412:
  movzbl (%r14,%rdi,1),%r9d
  lea    (%r14,%rax,1),%rcx
  movslq %edi,%r13
  movzbl (%rcx),%edx
  cmp    %r9b,%sil
  jg     L16
  cmp    %dl,%sil
  jge    L180
  lea    -0x1(%r14,%rax,1),%rax
  xchg   %ax,%ax
L282:
  mov    %rax,%rcx
  movzbl (%rax),%edx
  sub    $0x1,%rax
  sub    $0x1,%ebx
  cmp    %dl,%sil
  jl     L282
L180:
  cmp    %edi,%ebx
  jge    L367
L457:
  test   %ebx,%ebx
  jg     L318
  cmp    %r13d,%ebp
  jle    L458
L304:
  sub    %r13d,%ebp
  add    %r13,%r14
  jmp    L616
  nopl   0x0(%rax,%rax,1)
L367:
  sub    $0x1,%ebx
  mov    %dl,(%r14,%rdi,1)
  movslq %r8d,%r13
  mov    %r9b,(%rcx)
  cmp    %ebx,%r8d
  jg     L457
  movslq %ebx,%rax
L16:
  add    $0x1,%rdi
  add    $0x1,%r8d
  jmp    L412
L318:
  mov    %r13d,%r9d
  mov    %r14,%r12
  mov    %ebp,%r13d
  mov    %ebx,%ebp
L832:
  mov    %ebp,%eax
  mov    %ebp,%esi
  mov    $0x1,%ecx
  movslq %ebp,%r10
  sar    %eax
  cltq
  movzbl (%r12,%rax,1),%r11d
  xor    %eax,%eax
  nopl   0x0(%rax)
L610:
  movzbl (%r12,%rax,1),%r8d
  lea    (%r12,%r10,1),%rdx
  movslq %eax,%rbx
  movzbl (%rdx),%edi
  cmp    %r8b,%r11b
  jg     L766
  cmp    %dil,%r11b
  jge    L164
  lea    -0x1(%r12,%r10,1),%r10
  cs nopw 0x0(%rax,%rax,1)
L244:
  mov    %r10,%rdx
  movzbl (%r10),%edi
  sub    $0x1,%r10
  sub    $0x1,%esi
  cmp    %dil,%r11b
  jl     L244
L164:
  cmp    %eax,%esi
  jge    L53
L537:
  test   %esi,%esi
  jg     L574
L94:
  cmp    %ebx,%ebp
  jle    L516
  sub    %ebx,%ebp
  add    %rbx,%r12
  jmp    L832
  cs nopw 0x0(%rax,%rax,1)
L53:
  sub    $0x1,%esi
  mov    %dil,(%r12,%rax,1)
  movslq %ecx,%rbx
  mov    %r8b,(%rdx)
  cmp    %esi,%ecx
  jg     L537
  movslq %esi,%r10
L766:
  add    $0x1,%rax
  add    $0x1,%ecx
  jmp    L610
L516:
  mov    %r13d,%ebp
  movslq %r9d,%r13
  cmp    %r13d,%ebp
  jg     L304
L458:
  mov    %r15,%r9
  jmp    L329
L574:
  mov    %r12,%rdi
  mov    %r9d,0x6c(%rsp)
  call   <qsc>
  mov    0x6c(%rsp),%r9d
  jmp    L94
L541:
  mov    %r9d,0x54(%rsp)
  mov    %edx,0xc(%rsp)
  jmp    L807
```

assistant: ```c
void qsc(char *a, int n) {
  int i, j;
  char temp, p;
  p = *(a + (n >> 1));
  i = 0;
  j = n;
  do {
    while (*(a + i) < p)
      i++;
    while (*(a + j) > p)
      j--;
    if (i <= j) {
      temp = *(a + i);
      *(a + i) = *(a + j);
      *(a + j) = temp;
      i++;
      j--;
    }
  } while (i <= j);
  if (j > 0)
    qsc(a, j);
  if (n > i)
    qsc(a + i, n - i);
}
```