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

```asm
<dfct>:
  endbr64
  push   %r15
  push   %r14
  mov    %rsi,%r14
  push   %r13
  push   %r12
  mov    %edi,%r12d
  push   %rbp
  sar    %r12d
  push   %rbx
  sub    $0x48,%rsp
  mov    %edi,0x34(%rsp)
  test   %r12d,%r12d
  jle    L249
  movslq %edi,%rdi
  movslq %r12d,%rbp
  mov    %r12d,%edx
  lea    0x4(,%rdi,4),%rcx
  lea    0x0(,%rbp,4),%rax
  mov    %rcx,%r8
  lea    0x0(,%rdi,4),%rsi
  sub    %rax,%r8
  cmp    %r8,%rax
  jg     L125
  cmp    $0x1,%r12d
  je     L125
  lea    -0x1(%r12),%eax
  cmp    $0x2,%eax
  jbe    L210
  lea    -0x10(%r14,%rcx,1),%rdx
  mov    %r12d,%ecx
  mov    %r14,%rax
  shr    $0x2,%ecx
  sub    $0x1,%ecx
  shl    $0x4,%rcx
  lea    0x10(%r14,%rcx,1),%rcx
  nopw   0x0(%rax,%rax,1)
L265:
  movups (%rdx),%xmm0
  movups (%rax),%xmm2
  add    $0x10,%rax
  sub    $0x10,%rdx
  movups -0x10(%rax),%xmm1
  shufps $0x1b,%xmm0,%xmm0
  subps  %xmm0,%xmm2
  addps  %xmm0,%xmm1
  movups %xmm2,-0x10(%rax)
  shufps $0x1b,%xmm1,%xmm1
  movups %xmm1,0x10(%rdx)
  cmp    %rcx,%rax
  jne    L265
  mov    %r12d,%eax
  and    $0xfffffffc,%eax
  mov    %eax,%ecx
  cmp    %eax,%r12d
  je     L241
  mov    %r12d,%edx
  sub    %eax,%edx
  cmp    $0x1,%edx
  je     L117
L179:
  lea    (%r14,%rax,4),%r8
  not    %rax
  lea    (%rsi,%rax,4),%rax
  movq   (%r8),%xmm0
  add    %r14,%rax
  movq   (%rax),%xmm1
  movaps %xmm0,%xmm2
  shufps $0xe1,%xmm1,%xmm1
  addps  %xmm1,%xmm2
  subps  %xmm1,%xmm0
  shufps $0xe1,%xmm2,%xmm2
  movlps %xmm0,(%r8)
  movlps %xmm2,(%rax)
  mov    %edx,%eax
  and    $0xfffffffe,%eax
  add    %eax,%ecx
  cmp    %edx,%eax
  je     L241
L117:
  movslq %ecx,%rax
  lea    (%r14,%rax,4),%rdx
  mov    0x34(%rsp),%eax
  movss  (%rdx),%xmm0
  sub    %ecx,%eax
  cltq
  movaps %xmm0,%xmm2
  lea    (%r14,%rax,4),%rax
  movss  (%rax),%xmm1
  subss  %xmm1,%xmm2
  addss  %xmm1,%xmm0
  movss  %xmm2,(%rdx)
  movss  %xmm0,(%rax)
L241:
  lea    (%r14,%rdi,4),%rax
  movss  (%rax),%xmm7
  mov    %rax,0x38(%rsp)
  movss  %xmm7,0x30(%rsp)
L18:
  lea    0x4(%r14),%rax
  mov    %rax,(%rsp)
  nopw   0x0(%rax,%rax,1)
L95:
  mov    %r14,%rdx
  mov    $0x1,%esi
  mov    %r12d,%edi
  mov    %r12d,%r13d
  call   <ddct@plt>
  lea    0x0(,%rbp,4),%r15
  sar    %r13d
  lea    (%r14,%r15,1),%rbx
  cmp    $0x2,%r12d
  jne    L122
  movss  0x30(%rsp),%xmm7
  movss  (%r14),%xmm1
  movss  (%rbx),%xmm0
  movss  %xmm1,(%rbx)
  movaps %xmm7,%xmm1
  subss  %xmm0,%xmm1
  addss  %xmm7,%xmm0
  movss  %xmm1,(%r14)
  movaps %xmm0,%xmm7
  movss  %xmm0,0x30(%rsp)
L16:
  movslq %r13d,%rax
  lea    (%r14,%rax,4),%rdx
  lea    (%r12,%r13,1),%eax
  cltq
  movss  (%rdx),%xmm0
  lea    (%r14,%rax,4),%rax
  movss  (%rax),%xmm1
  movss  %xmm1,(%rdx)
  movss  %xmm0,(%rax)
  movss  0x4(%r14),%xmm1
  movaps %xmm7,%xmm0
  movss  (%r14),%xmm2
  mov    0x38(%rsp),%rax
  addss  %xmm1,%xmm0
  subss  %xmm1,%xmm7
  unpcklps %xmm2,%xmm0
  movlps %xmm0,(%r14)
  movss  %xmm7,(%rax)
L194:
  mov    0x34(%rsp),%edi
  add    $0x48,%rsp
  mov    %r14,%rsi
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    1070 <bitrv1@plt>
  nopl   0x0(%rax)
L122:
  mov    %r14,%rsi
  mov    %r12d,%edi
  call   <bitrv1@plt>
  movss  (%r14),%xmm1
  movss  0x30(%rsp),%xmm6
  movss  (%rbx),%xmm0
  movss  %xmm1,(%rbx)
  movaps %xmm6,%xmm1
  subss  %xmm0,%xmm1
  addss  %xmm6,%xmm0
  movss  %xmm1,(%r14)
  movss  %xmm0,0x30(%rsp)
  cmp    $0x1,%r13d
  je     L128
  lea    0x1(%rbp),%rax
  lea    0x4(%r15),%r9
  mov    %r13d,%edi
  mov    %rax,%rsi
  mov    %rax,0x20(%rsp)
  lea    -0x1(%r13),%eax
  shl    $0x2,%rdi
  lea    (%rax,%rsi,1),%rdx
  mov    %rax,%rcx
  lea    (%r14,%r9,1),%r11
  neg    %rax
  lea    0x0(,%rdx,4),%rsi
  lea    (%r15,%rax,4),%r8
  mov    %r11,0x18(%rsp)
  mov    %rsi,0x8(%rsp)
  lea    -0x10(%r15),%rdx
  lea    (%r8,%r15,1),%r10
  lea    0x0(,%rbp,8),%rsi
  mov    %rdx,0x28(%rsp)
  lea    -0x10(%rsi),%rax
  mov    %rax,0x10(%rsp)
  lea    0x14(%r14,%r15,1),%rax
  cmp    %rax,(%rsp)
  lea    0x14(%r14),%rax
  setae  %r11b
  cmp    %rax,0x18(%rsp)
  setae  %al
  or     %eax,%r11d
  cmp    %rsi,%rdx
  setge  %dl
  cmp    %r15,0x10(%rsp)
  setge  %al
  or     %edx,%eax
  and    %r11d,%eax
  cmp    $0x2,%r13d
  setne  %dl
  and    %edx,%eax
  cmp    %rbx,(%rsp)
  setae  %dl
  cmp    %r8,%rdi
  setle  %r11b
  or     %r11d,%edx
  mov    (%rsp),%r11
  and    %eax,%edx
  lea    (%rbx,%r15,1),%rax
  cmp    %rax,%r11
  setae  %al
  cmp    %rdi,%r10
  setge  %dil
  or     %edi,%eax
  and    %edx,%eax
  cmp    0x8(%rsp),%r8
  setge  %dl
  cmp    %r15,%r9
  setge  %dil
  or     %edi,%edx
  test   %dl,%al
  je     L259
  cmp    %r9,%rsi
  setle  %al
  cmp    0x8(%rsp),%r10
  setge  %dl
  or     %al,%dl
  je     L259
  lea    -0x2(%r13),%eax
  cmp    $0x2,%eax
  jbe    L195
  mov    0x10(%rsp),%r9
  mov    %ecx,%r10d
  mov    0x28(%rsp),%rax
  mov    %r11,%rdx
  shr    $0x2,%r10d
  mov    0x18(%rsp),%rdi
  add    %r14,%r9
  lea    -0x1(%r10),%r11d
  add    %r14,%rax
  lea    -0x10(%r9),%r8
  shl    $0x4,%r11
  mov    %r8,%r10
  sub    %r11,%r10
  jmp    L184
  xchg   %ax,%ax
L151:
  sub    $0x10,%r8
L184:
  movups (%r9),%xmm0
  movups (%rax),%xmm2
  add    $0x10,%rdi
  add    $0x10,%rdx
  movups -0x10(%rdx),%xmm5
  movups -0x10(%rdi),%xmm1
  sub    $0x10,%rax
  shufps $0x1b,%xmm0,%xmm0
  movups %xmm5,-0x10(%rdi)
  movups %xmm2,(%r9)
  movaps %xmm0,%xmm2
  addps  %xmm1,%xmm0
  mov    %r8,%r9
  subps  %xmm1,%xmm2
  shufps $0x1b,%xmm0,%xmm0
  movups %xmm2,-0x10(%rdx)
  movups %xmm0,0x10(%rax)
  cmp    %r8,%r10
  jne    L151
  mov    %ecx,%edx
  and    $0xfffffffc,%edx
  lea    0x1(%rdx),%eax
  cmp    %edx,%ecx
  je     L174
  mov    %r13d,%edi
  sub    %edx,%edi
  lea    -0x1(%rdi),%ecx
  cmp    $0x2,%edi
  je     L136
L276:
  mov    %rdx,%rdi
  mov    0x20(%rsp),%r8
  neg    %rdi
  shl    $0x2,%rdi
  add    %rdx,%r8
  lea    -0x8(%rsi,%rdi,1),%rsi
  lea    (%r14,%r8,4),%r9
  add    %r14,%rsi
  movq   (%r9),%xmm1
  lea    0x4(%r14,%rdx,4),%r8
  lea    -0x8(%r15,%rdi,1),%rdx
  movq   (%rsi),%xmm0
  add    %r14,%rdx
  mov    (%r8),%r10
  mov    (%rdx),%rdi
  shufps $0xe1,%xmm0,%xmm0
  mov    %r10,(%r9)
  movaps %xmm0,%xmm2
  addps  %xmm1,%xmm0
  mov    %rdi,(%rsi)
  subps  %xmm1,%xmm2
  shufps $0xe1,%xmm0,%xmm0
  movlps %xmm2,(%r8)
  movlps %xmm0,(%rdx)
  mov    %ecx,%edx
  and    $0xfffffffe,%edx
  add    %edx,%eax
  cmp    %ecx,%edx
  je     L174
L136:
  mov    %r12d,%edx
  sub    %eax,%edx
  lea    (%r12,%rdx,1),%ecx
  movslq %edx,%rdx
  movslq %ecx,%rcx
  lea    (%r14,%rcx,4),%rsi
  lea    (%r12,%rax,1),%ecx
  cltq
  movslq %ecx,%rcx
  movss  (%rsi),%xmm0
  lea    (%r14,%rcx,4),%rdi
  lea    (%r14,%rax,4),%rcx
  lea    (%r14,%rdx,4),%rax
  movss  (%rcx),%xmm3
  movss  (%rdi),%xmm1
  movss  (%rax),%xmm2
  movss  %xmm3,(%rdi)
  movss  %xmm2,(%rsi)
  movaps %xmm0,%xmm2
  addss  %xmm1,%xmm0
  subss  %xmm1,%xmm2
  movss  %xmm2,(%rcx)
  movss  %xmm0,(%rax)
L174:
  add    %r13d,%r12d
  movslq %r13d,%rbp
  movslq %r12d,%r12
  lea    (%r14,%rbp,4),%rdx
  lea    (%r14,%r12,4),%rax
  movss  (%rdx),%xmm0
  mov    %r13d,%r12d
  movss  (%rax),%xmm1
  movss  %xmm1,(%rdx)
  movss  %xmm0,(%rax)
  jmp    L95
  nopl   0x0(%rax)
L259:
  mov    (%rsp),%rsi
  lea    -0x2(%r13),%edx
  mov    %r14,%rax
  lea    (%rsi,%rdx,4),%rdx
  nopw   0x0(%rax,%rax,1)
L256:
  movss  -0x4(%rbx,%rbp,4),%xmm0
  movss  -0x4(%rbx),%xmm2
  movss  0x4(%rax),%xmm3
  movss  0x4(%rax,%rbp,4),%xmm1
  movss  %xmm3,0x4(%rax,%rbp,4)
  add    $0x4,%rax
  movss  %xmm2,-0x4(%rbx,%rbp,4)
  movaps %xmm0,%xmm2
  addss  %xmm1,%xmm0
  sub    $0x4,%rbx
  subss  %xmm1,%xmm2
  movss  %xmm2,(%rax)
  movss  %xmm0,(%rbx)
  cmp    %rdx,%rax
  jne    L256
  jmp    L174
L195:
  xor    %edx,%edx
  mov    $0x1,%eax
  jmp    L276
L125:
  lea    -0x1(%r12),%ecx
  mov    %r14,%rdx
  lea    (%r14,%rsi,1),%rax
  lea    0x4(%r14,%rcx,4),%rcx
  nopl   0x0(%rax)
L154:
  movss  (%rdx),%xmm0
  movss  (%rax),%xmm1
  add    $0x4,%rdx
  sub    $0x4,%rax
  movaps %xmm0,%xmm2
  addss  %xmm1,%xmm0
  subss  %xmm1,%xmm2
  movss  %xmm2,-0x4(%rdx)
  movss  %xmm0,0x4(%rax)
  cmp    %rdx,%rcx
  jne    L154
  lea    (%r14,%rdi,4),%rax
  movss  (%rax),%xmm7
  mov    %rax,0x38(%rsp)
  movss  %xmm7,0x30(%rsp)
  cmp    $0x1,%r12d
  jg     L18
L78:
  movss  0x4(%r14),%xmm1
  movaps %xmm7,%xmm0
  movss  (%r14),%xmm2
  cmpl   $0x3,0x34(%rsp)
  addss  %xmm1,%xmm0
  subss  %xmm1,%xmm7
  unpcklps %xmm2,%xmm0
  movlps %xmm0,(%r14)
  movss  %xmm7,(%rax)
  je     L194
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L249:
  movslq 0x34(%rsp),%rax
  lea    (%rsi,%rax,4),%rax
  movss  (%rax),%xmm7
  mov    %rax,0x38(%rsp)
  movss  %xmm7,0x30(%rsp)
  jmp    L78
L210:
  xor    %eax,%eax
  xor    %ecx,%ecx
  jmp    L179
L128:
  mov    $0x3,%r12d
  movaps %xmm0,%xmm7
  jmp    L16
```

assistant: ```c
void dfct(int n, float *a) {
  void ddct(int n, int isgn, float *a);
  void bitrv1(int n, float *a);
  int j, k, m, mh;
  float xr, xi, yr, yi, an;
  m = n >> 1;
  for (j = 0; j < m; j++) {
    k = n - j;
    xr = a[j] + a[k];
    a[j] -= a[k];
    a[k] = xr;
  }
  an = a[n];
  while (m >= 2) {
    ddct(m, 1, a);
    if (m > 2) {
      bitrv1(m, a);
    }
    mh = m >> 1;
    xi = a[m];
    a[m] = a[0];
    a[0] = an - xi;
    an += xi;
    for (j = 1; j < mh; j++) {
      k = m - j;
      xr = a[m + k];
      xi = a[m + j];
      yr = a[j];
      yi = a[k];
      a[m + j] = yr;
      a[m + k] = yi;
      a[j] = xr - xi;
      a[k] = xr + xi;
    }
    xr = a[mh];
    a[mh] = a[m + mh];
    a[m + mh] = xr;
    m = mh;
  }
  xi = a[1];
  a[1] = a[0];
  a[0] = an + xi;
  a[n] = an - xi;
  if (n > 2) {
    bitrv1(n, a);
  }
}
```