user: What is the c source code of the assembly code below:

```asm
<bn_mul_high>:
  endbr64
  push   %r15
  mov    %rsi,%r10
  push   %r14
  mov    %rdx,%r14
  push   %r13
  push   %r12
  mov    %r9,%r12
  push   %rbp
  push   %rbx
  mov    %rdi,%rbx
  mov    %r10,%rdi
  sub    $0x38,%rsp
  mov    %rcx,0x8(%rsp)
  mov    %r8d,%ecx
  shr    $0x1f,%ecx
  mov    %r8d,0x1c(%rsp)
  add    %r8d,%ecx
  mov    %r10,0x20(%rsp)
  sar    %ecx
  movslq %ecx,%rax
  lea    0x0(,%rax,8),%r15
  mov    %eax,%edx
  mov    %rax,%r13
  lea    (%rsi,%r15,1),%r9
  mov    %r9,%rsi
  mov    %r9,0x28(%rsp)
  call   <bn_cmp_words@plt>
  mov    %r15,0x10(%rsp)
  add    %r14,%r15
  mov    %r13d,%edx
  mov    %r15,%rdi
  mov    %r14,%rsi
  mov    %eax,%ebp
  call   <bn_cmp_words@plt>
  mov    0x10(%rsp),%rdi
  mov    0x20(%rsp),%r10
  mov    %eax,%r8d
  lea    0x0(%rbp,%rbp,2),%eax
  mov    0x28(%rsp),%r9
  add    %r8d,%eax
  lea    (%rbx,%rdi,1),%rbp
  cmp    $0x2,%eax
  je     L304
  jg     L282
  cmp    $0xfffffffc,%eax
  je     L278
  cmp    $0xfffffffe,%eax
  jne    L253
  mov    %r9,%rsi
  mov    %r10,%rdx
  mov    %r13d,%ecx
  mov    %rbx,%rdi
  mov    %r9,0x28(%rsp)
  call   <bn_sub_words@plt>
  mov    %r13d,%ecx
  mov    %r14,%rdx
  mov    %r15,%rsi
  mov    %rbp,%rdi
  call   <bn_sub_words@plt>
  movl   $0x1,0x20(%rsp)
  mov    0x28(%rsp),%r9
  cs nopw 0x0(%rax,%rax,1)
L157:
  movslq 0x1c(%rsp),%rax
  mov    %r9,0x28(%rsp)
  lea    (%r12,%rax,8),%r14
  cmp    $0x8,%r13d
  je     L275
  mov    %r14,%r8
  mov    %r13d,%ecx
  mov    %rbp,%rdx
  mov    %rbx,%rsi
  mov    %r12,%rdi
  call   <bn_mul_recursive@plt>
  mov    0x28(%rsp),%rsi
  mov    %r14,%r8
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    %rbx,%rdi
  call   <bn_mul_recursive@plt>
L119:
  mov    0x1c(%rsp),%eax
  mov    %rbx,%rsi
  add    %r13d,%eax
  cltq
  lea    (%r12,%rax,8),%r15
  mov    0x8(%rsp),%rax
  test   %rax,%rax
  je     L83
  mov    %r13d,%ecx
  mov    %rax,%rdx
  mov    %r15,%rdi
  call   <bn_add_words@plt>
  mov    %r15,%rsi
L83:
  mov    0x20(%rsp),%r8d
  mov    %r13d,%ecx
  mov    %r12,%rdx
  mov    %r14,%rdi
  test   %r8d,%r8d
  je     L100
  call   <bn_sub_words@plt>
  mov    0x8(%rsp),%rax
  test   %rax,%rax
  je     L170
L11:
  mov    0x10(%rsp),%rsi
  mov    %r13d,%ecx
  mov    %r14,%rdx
  mov    %r15,%rdi
  add    %rax,%rsi
  call   <bn_sub_words@plt>
  mov    0x8(%rsp),%rdx
  mov    %r15,%rsi
  mov    %r13d,%ecx
  mov    %r14,%rdi
  call   <bn_add_words@plt>
  mov    %r14,%rsi
  mov    %eax,0x8(%rsp)
L288:
  mov    %r13d,%ecx
  mov    %rbx,%rdx
  mov    %r14,%rdi
  call   <bn_add_words@plt>
  add    0x8(%rsp),%eax
  mov    %r13d,%ecx
  mov    %r12,%rdx
  mov    0x10(%rsp),%r8
  mov    %eax,0x8(%rsp)
  mov    %r14,%rsi
  mov    %r14,%rdi
  mov    0x20(%rsp),%eax
  add    %r12,%r8
  test   %eax,%eax
  mov    %r8,0x10(%rsp)
  je     L122
  call   <bn_sub_words@plt>
  mov    0x8(%rsp),%r14d
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    %rbx,%rsi
  mov    %rbx,%rdi
  sub    %eax,%r14d
  call   <bn_add_words@plt>
  mov    %r13d,%ecx
  mov    %rbp,%rdx
  mov    %rbx,%rsi
  mov    %rbx,%rdi
  mov    %rax,%r12
  call   <bn_add_words@plt>
  mov    0x10(%rsp),%rdx
  mov    %r13d,%ecx
  mov    %rbx,%rsi
  mov    %rbx,%rdi
  add    %eax,%r12d
  call   <bn_sub_words@plt>
  mov    %rax,%r8
  mov    %r12d,%eax
  sub    %r8d,%eax
L290:
  test   %r14d,%r14d
  je     L194
  jle    L89
  movslq %r14d,%rdx
  nopl   0x0(%rax)
L164:
  xor    %ecx,%ecx
  add    (%rbx),%rdx
  setb   %cl
  mov    %rdx,(%rbx)
  add    $0x8,%rbx
  mov    $0x1,%edx
  test   %rcx,%rcx
  jne    L164
L194:
  test   %eax,%eax
  je     L306
  jle    L106
  cltq
  nopl   (%rax)
L303:
  xor    %edx,%edx
  add    0x0(%rbp),%rax
  setb   %dl
  mov    %rax,0x0(%rbp)
  add    $0x8,%rbp
  mov    $0x1,%eax
  test   %rdx,%rdx
  jne    L303
L306:
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L282:
  cmp    $0x4,%eax
  jne    L253
  mov    %r9,%rdx
  mov    %r10,%rsi
  mov    %r13d,%ecx
  mov    %rbx,%rdi
  mov    %r9,0x28(%rsp)
  call   <bn_sub_words@plt>
  mov    %r13d,%ecx
  mov    %r14,%rdx
  mov    %r15,%rsi
  mov    %rbp,%rdi
  call   <bn_sub_words@plt>
  movl   $0x0,0x20(%rsp)
  mov    0x28(%rsp),%r9
  jmp    L157
  nopw   0x0(%rax,%rax,1)
L122:
  call   <bn_add_words@plt>
  mov    0x8(%rsp),%r14d
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    %rbx,%rsi
  mov    %rbx,%rdi
  add    %eax,%r14d
  call   <bn_add_words@plt>
  mov    %r13d,%ecx
  mov    %rbp,%rdx
  mov    %rbx,%rsi
  mov    %rbx,%rdi
  mov    %rax,%r12
  call   <bn_add_words@plt>
  mov    0x10(%rsp),%rdx
  mov    %r13d,%ecx
  mov    %rbx,%rsi
  mov    %rbx,%rdi
  add    %eax,%r12d
  call   <bn_add_words@plt>
  add    %r12d,%eax
  jmp    L290
  nopl   0x0(%rax,%rax,1)
L100:
  call   <bn_add_words@plt>
  mov    0x8(%rsp),%rax
  test   %rax,%rax
  jne    L11
L170:
  cmpl   $0x1,0x1c(%rsp)
  jle    L25
  xor    %eax,%eax
  nopl   0x0(%rax)
L228:
  mov    (%r14,%rax,8),%rdx
  neg    %rdx
  mov    %rdx,(%r15,%rax,8)
  add    $0x1,%rax
  cmp    %eax,%r13d
  jg     L228
L25:
  movl   $0x0,0x8(%rsp)
  mov    %r15,%rsi
  jmp    L288
  nopl   0x0(%rax)
L89:
  mov    %r14d,%edx
  neg    %edx
  movslq %edx,%rdx
  jmp    L117
  nopw   0x0(%rax,%rax,1)
L30:
  mov    $0x1,%edx
L117:
  mov    (%rbx),%rcx
  add    $0x8,%rbx
  mov    %rcx,%rsi
  sub    %rdx,%rsi
  mov    %rsi,-0x8(%rbx)
  cmp    %rcx,%rdx
  ja     L30
  jmp    L194
  nopl   0x0(%rax,%rax,1)
L106:
  neg    %eax
  cltq
  jmp    L254
  cs nopw 0x0(%rax,%rax,1)
L81:
  mov    $0x1,%eax
L254:
  mov    0x0(%rbp),%rdx
  add    $0x8,%rbp
  mov    %rdx,%rcx
  sub    %rax,%rcx
  mov    %rcx,-0x8(%rbp)
  cmp    %rdx,%rax
  ja     L81
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L275:
  mov    %rbp,%rdx
  mov    %rbx,%rsi
  mov    %r12,%rdi
  call   <bn_mul_comba8@plt>
  mov    0x28(%rsp),%rsi
  mov    %r15,%rdx
  mov    %rbx,%rdi
  call   <bn_mul_comba8@plt>
  jmp    L119
  nopl   0x0(%rax,%rax,1)
L253:
  movl   $0x0,0x20(%rsp)
  jmp    L157
  nopl   (%rax)
L304:
  mov    %r9,%rdx
  mov    %r10,%rsi
  mov    %r13d,%ecx
  mov    %rbx,%rdi
  mov    %r9,0x28(%rsp)
  call   <bn_sub_words@plt>
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    %r14,%rsi
  mov    %rbp,%rdi
  call   <bn_sub_words@plt>
  movl   $0x1,0x20(%rsp)
  mov    0x28(%rsp),%r9
  jmp    L157
  nopl   0x0(%rax)
L278:
  mov    %r9,%rsi
  mov    %r10,%rdx
  mov    %r13d,%ecx
  mov    %rbx,%rdi
  mov    %r9,0x28(%rsp)
  call   <bn_sub_words@plt>
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    %r14,%rsi
  mov    %rbp,%rdi
  call   <bn_sub_words@plt>
  movl   $0x0,0x20(%rsp)
  mov    0x28(%rsp),%r9
  jmp    L157
```

assistant: ```c
void bn_mul_high(unsigned long long *r, unsigned long long *a, unsigned long long *b, unsigned long long *l, int n2, unsigned long long *t) {
  int i, n;
  int c1, c2;
  int neg, oneg, zero;
  unsigned long long ll, lc, *lp, *mp;
  n = n2 / 2;
  neg = zero = 0;
  c1 = bn_cmp_words(&(a[0]), &(a[n]), n);
  c2 = bn_cmp_words(&(b[n]), &(b[0]), n);
  switch (c1 * 3 + c2) {
  case -4:
    bn_sub_words(&(r[0]), &(a[n]), &(a[0]), n);
    bn_sub_words(&(r[n]), &(b[0]), &(b[n]), n);
    break;
  case -3:
    zero = 1;
    break;
  case -2:
    bn_sub_words(&(r[0]), &(a[n]), &(a[0]), n);
    bn_sub_words(&(r[n]), &(b[n]), &(b[0]), n);
    neg = 1;
    break;
  case -1:
  case 0:
  case 1:
    zero = 1;
    break;
  case 2:
    bn_sub_words(&(r[0]), &(a[0]), &(a[n]), n);
    bn_sub_words(&(r[n]), &(b[0]), &(b[n]), n);
    neg = 1;
    break;
  case 3:
    zero = 1;
    break;
  case 4:
    bn_sub_words(&(r[0]), &(a[0]), &(a[n]), n);
    bn_sub_words(&(r[n]), &(b[n]), &(b[0]), n);
    break;
  }
  oneg = neg;
  if (n == 8) {
    bn_mul_comba8(&(t[0]), &(r[0]), &(r[n]));
    bn_mul_comba8(r, &(a[n]), &(b[n]));
  } else {
    bn_mul_recursive(&(t[0]), &(r[0]), &(r[n]), n, &(t[n2]));
    bn_mul_recursive(r, &(a[n]), &(b[n]), n, &(t[n2]));
  }
  if (l != NULL) {
    lp = &(t[n2 + n]);
    c1 = (int)(bn_add_words(lp, &(r[0]), &(l[0]), n));
  } else {
    c1 = 0;
    lp = &(r[0]);
  }
  if (neg)
    neg = (int)(bn_sub_words(&(t[n2]), lp, &(t[0]), n));
  else {
    bn_add_words(&(t[n2]), lp, &(t[0]), n);
    neg = 0;
  }
  if (l != NULL) {
    bn_sub_words(&(t[n2 + n]), &(l[n]), &(t[n2]), n);
  } else {
    lp = &(t[n2 + n]);
    mp = &(t[n2]);
    for (i = 0; i < n; i++)
      lp[i] = ((~mp[i]) + 1) & (0xffffffffffffffffLL);
  }
  if (l != NULL) {
    lp = &(t[n2]);
    c1 = (int)(bn_add_words(lp, &(t[n2 + n]), &(l[0]), n));
  } else {
    lp = &(t[n2 + n]);
    c1 = 0;
  }
  c1 += (int)(bn_add_words(&(t[n2]), lp, &(r[0]), n));
  if (oneg)
    c1 -= (int)(bn_sub_words(&(t[n2]), &(t[n2]), &(t[0]), n));
  else
    c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), &(t[0]), n));
  c2 = (int)(bn_add_words(&(r[0]), &(r[0]), &(t[n2 + n]), n));
  c2 += (int)(bn_add_words(&(r[0]), &(r[0]), &(r[n]), n));
  if (oneg)
    c2 -= (int)(bn_sub_words(&(r[0]), &(r[0]), &(t[n]), n));
  else
    c2 += (int)(bn_add_words(&(r[0]), &(r[0]), &(t[n]), n));
  if (c1 != 0) {
    i = 0;
    if (c1 > 0) {
      lc = c1;
      do {
        ll = (r[i] + lc) & (0xffffffffffffffffLL);
        r[i++] = ll;
        lc = (lc > ll);
      } while (lc);
    } else {
      lc = -c1;
      do {
        ll = r[i];
        r[i++] = (ll - lc) & (0xffffffffffffffffLL);
        lc = (lc > ll);
      } while (lc);
    }
  }
  if (c2 != 0) {
    i = n;
    if (c2 > 0) {
      lc = c2;
      do {
        ll = (r[i] + lc) & (0xffffffffffffffffLL);
        r[i++] = ll;
        lc = (lc > ll);
      } while (lc);
    } else {
      lc = -c2;
      do {
        ll = r[i];
        r[i++] = (ll - lc) & (0xffffffffffffffffLL);
        lc = (lc > ll);
      } while (lc);
    }
  }
}
```