user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<dfct>:
  endbr64
  push   %r15
  mov    %rcx,%r10
  push   %r14
  push   %r13
  push   %r12
  mov    %rsi,%r12
  push   %rbp
  push   %rbx
  mov    %rdx,%rbx
  sub    $0x58,%rsp
  mov    (%rcx),%r15d
  mov    %edi,0xc(%rsp)
  lea    0x0(,%r15,8),%eax
  mov    %r8,0x28(%rsp)
  cmp    %edi,%eax
  jl     L25
L212:
  mov    0x4(%r10),%r14d
  mov    0xc(%rsp),%esi
  lea    (%r14,%r14,1),%eax
  mov    %esi,%edi
  sar    %edi
  cmp    %esi,%eax
  jl     L75
L185:
  movslq 0xc(%rsp),%r8
  movss  (%r12),%xmm1
  movslq %edi,%rdx
  movss  (%r12,%rdx,4),%xmm0
  lea    0x0(,%rdx,4),%rax
  mov    %r8,%rsi
  shl    $0x2,%r8
  movaps %xmm1,%xmm2
  lea    (%r12,%r8,1),%rcx
  movss  (%rcx),%xmm3
  mov    %rcx,0x48(%rsp)
  addss  %xmm3,%xmm2
  subss  %xmm3,%xmm1
  movss  %xmm1,(%r12)
  movaps %xmm2,%xmm1
  subss  %xmm0,%xmm1
  addss  %xmm2,%xmm0
  movss  %xmm1,(%rbx)
  movss  %xmm0,(%rbx,%rdx,4)
  cmp    $0x2,%esi
  jle    L160
  mov    %esi,%ebp
  sar    $0x2,%ebp
  cmp    $0x7,%esi
  jle    L67
  mov    %r8,%rcx
  lea    -0x4(,%rdx,4),%rdx
  movslq %ebp,%r13
  sub    %rax,%rcx
  mov    $0x1,%eax
  add    %r12,%rcx
  nopl   0x0(%rax)
L135:
  movss  (%r12,%rax,4),%xmm2
  movss  (%rcx,%rdx,1),%xmm5
  movss  (%r12,%rdx,1),%xmm1
  movss  (%rcx,%rax,4),%xmm4
  movaps %xmm2,%xmm0
  subss  %xmm5,%xmm2
  addss  %xmm5,%xmm0
  movaps %xmm1,%xmm3
  subss  %xmm4,%xmm1
  addss  %xmm4,%xmm3
  movss  %xmm2,(%r12,%rax,4)
  movss  %xmm1,(%r12,%rdx,1)
  movaps %xmm0,%xmm1
  subss  %xmm3,%xmm1
  addss  %xmm3,%xmm0
  movss  %xmm1,(%rbx,%rax,4)
  add    $0x1,%rax
  movss  %xmm0,(%rbx,%rdx,1)
  sub    $0x4,%rdx
  cmp    %rax,%r13
  jne    L135
L65:
  mov    0xc(%rsp),%edx
  lea    (%r12,%r13,4),%rax
  movslq %r15d,%r15
  mov    %r12,%rsi
  movss  (%rax),%xmm0
  mov    %r10,0x30(%rsp)
  sub    %ebp,%edx
  mov    %r8,0x20(%rsp)
  movslq %edx,%rdx
  mov    %edi,0x18(%rsp)
  lea    (%r12,%rdx,4),%rdx
  addss  (%rdx),%xmm0
  movss  %xmm0,(%rbx,%r13,4)
  movss  (%rax),%xmm0
  subss  (%rdx),%xmm0
  mov    %r14d,%edx
  movss  %xmm0,(%rax)
  mov    0x28(%rsp),%rax
  lea    (%rax,%r15,4),%rax
  mov    %rax,%rcx
  mov    %rax,0x10(%rsp)
  call   <dctsub@plt>
  mov    0x18(%rsp),%edi
  mov    0x20(%rsp),%r8
  mov    0x30(%rsp),%r10
  cmp    $0x4,%edi
  lea    -0x4(%r12,%r8,1),%r9
  lea    -0x2(%rdi),%r8d
  jg     L200
  je     L95
  movss  (%r12),%xmm0
  subss  0x4(%r12),%xmm0
  movss  %xmm0,(%r9)
  movss  0x4(%r12),%xmm0
  addss  (%r12),%xmm0
  movss  %xmm0,0x4(%r12)
  cmp    $0x1,%r8d
  jle    L4
L163:
  movslq %r8d,%r8
  nop
L112:
  movss  (%r12,%r8,4),%xmm0
  addss  0x4(%r12,%r8,4),%xmm0
  movss  %xmm0,0x4(%r12,%r8,8)
  movss  (%r12,%r8,4),%xmm0
  subss  0x4(%r12,%r8,4),%xmm0
  movss  %xmm0,-0x4(%r12,%r8,8)
  sub    $0x2,%r8
  cmp    $0x1,%r8d
  jg     L112
L4:
  lea    0x4(%rbx),%rax
  mov    $0x2,%r15d
  mov    %rax,0x20(%rsp)
  lea    0x8(%r10),%rax
  mov    %rax,0x40(%rsp)
  mov    $0x8,%eax
  cmp    $0x1,%ebp
  jle    L161
  mov    %r12,%rax
  mov    %r14d,0x18(%rsp)
  mov    %r15d,%r12d
  mov    %r13,%r14
  mov    %rax,%r15
  nopl   0x0(%rax)
L1:
  mov    0x10(%rsp),%rcx
  mov    0x18(%rsp),%edx
  mov    %rbx,%rsi
  mov    %ebp,%edi
  movslq %r12d,%r13
  call   <dctsub@plt>
  mov    0xc(%rsp),%eax
  lea    (%r15,%r13,4),%r10
  sub    %r12d,%eax
  cltq
  lea    (%r15,%rax,4),%r11
  cmp    $0x4,%ebp
  jg     L77
  je     L239
  movss  (%rbx),%xmm0
  subss  0x4(%rbx),%xmm0
  movss  %xmm0,(%r11)
  movss  (%rbx),%xmm0
  addss  0x4(%rbx),%xmm0
  movss  %xmm0,(%r10)
  cmp    $0x3,%ebp
  jne    L153
L217:
  lea    0x0(,%r12,4),%eax
  cltq
  lea    0x0(,%rax,4),%rcx
  sub    %r13,%rax
  lea    (%r15,%rax,4),%rdx
  mov    $0x2,%eax
  nopl   (%rax)
L242:
  movss  (%rbx,%rax,4),%xmm0
  subss  0x4(%rbx,%rax,4),%xmm0
  movss  %xmm0,(%rdx)
  movss  (%rbx,%rax,4),%xmm0
  addss  0x4(%rbx,%rax,4),%xmm0
  add    $0x2,%rax
  movss  %xmm0,(%rdx,%r13,8)
  add    %rcx,%rdx
  cmp    %eax,%ebp
  jg     L242
L153:
  mov    %ebp,%edi
  mov    0x20(%rsp),%r9
  lea    0x0(%rbp,%rbp,1),%eax
  add    %r12d,%r12d
  sar    %edi
  cltq
  lea    0x0(,%r14,4),%rcx
  lea    -0x1(%rdi),%esi
  lea    (%rbx,%rax,4),%rdx
  add    %r14,%rsi
  lea    (%rbx,%rcx,1),%rax
  neg    %rcx
  lea    (%r9,%rsi,4),%rsi
  nopw   0x0(%rax,%rax,1)
L29:
  movss  (%rdx),%xmm0
  subss  (%rax),%xmm0
  add    $0x4,%rax
  sub    $0x4,%rdx
  movss  %xmm0,-0x4(%rax,%rcx,1)
  movss  0x4(%rdx),%xmm0
  addss  -0x4(%rax),%xmm0
  movss  %xmm0,0x4(%rdx,%rcx,1)
  cmp    %rax,%rsi
  jne    L29
  add    %edi,%ebp
  movslq %edi,%r14
  movslq %ebp,%rbp
  movss  (%rbx,%rbp,4),%xmm0
  movss  %xmm0,(%rbx,%r14,4)
  cmp    $0x1,%edi
  je     L119
  mov    %edi,%ebp
  jmp    L1
  cs nopw 0x0(%rax,%rax,1)
L160:
  movss  (%r12),%xmm0
  movss  %xmm0,0x4(%r12)
  movss  (%rbx),%xmm0
  movss  %xmm0,0x8(%r12)
  movss  0x4(%rbx),%xmm0
L27:
  movss  %xmm0,(%r12)
  add    $0x58,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L77:
  mov    0x40(%rsp),%rsi
  mov    %rbx,%rdx
  mov    %ebp,%edi
  mov    %r10,0x38(%rsp)
  mov    %r11,0x30(%rsp)
  call   <bitrv2@plt>
  mov    0x28(%rsp),%rdx
  mov    %rbx,%rsi
  mov    %ebp,%edi
  call   <cftfsub@plt>
  mov    0x10(%rsp),%rcx
  mov    0x18(%rsp),%edx
  mov    %ebp,%edi
  mov    %rbx,%rsi
  call   <rftfsub@plt>
  mov    0x30(%rsp),%r11
  mov    0x38(%rsp),%r10
L209:
  movss  (%rbx),%xmm0
  subss  0x4(%rbx),%xmm0
  movss  %xmm0,(%r11)
  movss  0x4(%rbx),%xmm0
  addss  (%rbx),%xmm0
  movss  %xmm0,(%r10)
  jmp    L217
  xchg   %ax,%ax
L239:
  mov    0x28(%rsp),%rdx
  mov    %rbx,%rsi
  mov    $0x4,%edi
  mov    %r10,0x38(%rsp)
  mov    %r11,0x30(%rsp)
  call   <cftfsub@plt>
  mov    0x30(%rsp),%r11
  mov    0x38(%rsp),%r10
  jmp    L209
  nopl   0x0(%rax,%rax,1)
L119:
  mov    %r15,%rax
  mov    %r12d,%r15d
  mov    %rax,%r12
  movslq %r15d,%rax
  shl    $0x2,%rax
L161:
  movss  (%rbx),%xmm0
  movss  %xmm0,(%r12,%rax,1)
  movss  0x8(%rbx),%xmm0
  subss  0x4(%rbx),%xmm0
  mov    0x48(%rsp),%rax
  movss  %xmm0,(%rax)
  movss  0x8(%rbx),%xmm0
  addss  0x4(%rbx),%xmm0
  jmp    L27
L75:
  mov    0x28(%rsp),%rsi
  movslq %r15d,%rax
  mov    %r10,0x18(%rsp)
  mov    %edi,0x10(%rsp)
  lea    (%rsi,%rax,4),%rdx
  mov    %r10,%rsi
  call   <makect@plt>
  mov    0x10(%rsp),%edi
  mov    0x18(%rsp),%r10
  mov    %edi,%r14d
  jmp    L185
L25:
  mov    %edi,%r15d
  mov    %r8,%rdx
  mov    %rcx,%rsi
  mov    %rcx,0x10(%rsp)
  sar    $0x3,%r15d
  mov    %r15d,%edi
  call   <makewt@plt>
  mov    0x10(%rsp),%r10
  jmp    L212
L67:
  movslq %ebp,%r13
  jmp    L65
L200:
  lea    0x8(%r10),%rsi
  mov    %r12,%rdx
  mov    %r8d,0x38(%rsp)
  mov    %r9,0x30(%rsp)
  mov    %r10,0x20(%rsp)
  mov    %edi,0x18(%rsp)
  call   <bitrv2@plt>
  mov    0x28(%rsp),%rdx
  mov    0x18(%rsp),%edi
  mov    %r12,%rsi
  call   <cftfsub@plt>
  mov    0x10(%rsp),%rcx
  mov    %r14d,%edx
  mov    %r12,%rsi
  mov    0x18(%rsp),%edi
  call   <rftfsub@plt>
  mov    0x20(%rsp),%r10
  mov    0x30(%rsp),%r9
  mov    0x38(%rsp),%r8d
L245:
  movss  (%r12),%xmm0
  subss  0x4(%r12),%xmm0
  movss  %xmm0,(%r9)
  movss  0x4(%r12),%xmm0
  addss  (%r12),%xmm0
  movss  %xmm0,0x4(%r12)
  jmp    L163
L95:
  mov    0x28(%rsp),%rdx
  mov    %r12,%rsi
  mov    $0x4,%edi
  mov    %r10,0x30(%rsp)
  mov    %r8d,0x20(%rsp)
  mov    %r9,0x18(%rsp)
  call   <cftfsub@plt>
  mov    0x18(%rsp),%r9
  mov    0x20(%rsp),%r8d
  mov    0x30(%rsp),%r10
  jmp    L245
```

assistant: ```c
void dfct(int n, float *a, float *t, int *ip, float *w) {
  int j, k, l, m, mh, nw, nc;
  float xr, xi, yr, yi;
  nw = ip[0];
  if (n > (nw << 3)) {
    nw = n >> 3;
    makewt(nw, ip, w);
  }
  nc = ip[1];
  if (n > (nc << 1)) {
    nc = n >> 1;
    makect(nc, ip, w + nw);
  }
  m = n >> 1;
  yi = a[m];
  xi = a[0] + a[n];
  a[0] -= a[n];
  t[0] = xi - yi;
  t[m] = xi + yi;
  if (n > 2) {
    mh = m >> 1;
    for (j = 1; j < mh; j++) {
      k = m - j;
      xr = a[j] - a[n - j];
      xi = a[j] + a[n - j];
      yr = a[k] - a[n - k];
      yi = a[k] + a[n - k];
      a[j] = xr;
      a[k] = yr;
      t[j] = xi - yi;
      t[k] = xi + yi;
    }
    t[mh] = a[mh] + a[n - mh];
    a[mh] -= a[n - mh];
    dctsub(m, a, nc, w + nw);
    if (m > 4) {
      bitrv2(m, ip + 2, a);
      cftfsub(m, a, w);
      rftfsub(m, a, nc, w + nw);
    } else if (m == 4) {
      cftfsub(m, a, w);
    }
    a[n - 1] = a[0] - a[1];
    a[1] = a[0] + a[1];
    for (j = m - 2; j >= 2; j -= 2) {
      a[2 * j + 1] = a[j] + a[j + 1];
      a[2 * j - 1] = a[j] - a[j + 1];
    }
    l = 2;
    m = mh;
    while (m >= 2) {
      dctsub(m, t, nc, w + nw);
      if (m > 4) {
        bitrv2(m, ip + 2, t);
        cftfsub(m, t, w);
        rftfsub(m, t, nc, w + nw);
      } else if (m == 4) {
        cftfsub(m, t, w);
      }
      a[n - l] = t[0] - t[1];
      a[l] = t[0] + t[1];
      k = 0;
      for (j = 2; j < m; j += 2) {
        k += l << 2;
        a[k - l] = t[j] - t[j + 1];
        a[k + l] = t[j] + t[j + 1];
      }
      l <<= 1;
      mh = m >> 1;
      for (j = 0; j < mh; j++) {
        k = m - j;
        t[j] = t[m + k] - t[m + j];
        t[k] = t[m + k] + t[m + j];
      }
      t[mh] = t[m + mh];
      m = mh;
    }
    a[l] = t[0];
    a[n] = t[2] - t[1];
    a[0] = t[2] + t[1];
  } else {
    a[1] = a[0];
    a[2] = t[0];
    a[0] = t[1];
  }
}
```