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

```asm
<matprod_trans12_sub>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,-0x98(%rbp)
  mov    %rsi,-0x60(%rbp)
  mov    %rdx,-0x70(%rbp)
  mov    %ecx,%r14d
  mov    %ecx,-0x54(%rbp)
  mov    %r8d,%r15d
  mov    %r8d,-0x64(%rbp)
  mov    %r9d,%ebx
  mov    %r9d,-0x68(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  mov    %rsp,-0x90(%rbp)
  mov    $0x1,%edi
  call   <assert@plt>
  mov    $0x1,%edi
  call   <assert@plt>
  mov    $0x1,%edi
  call   <assert@plt>
  cmp    $0x1,%ebx
  setg   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  cmp    $0x1,%r15d
  setg   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  cmp    $0x1,%r14d
  setg   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  cmpl   $0x1,0x10(%rbp)
  setg   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  cmp    $0x2,%ebx
  je     L11
  cmpl   $0x7f,0x10(%rbp)
  jg     L219
  mov    $0x800,%eax
  cltd
  idivl  0x10(%rbp)
  and    $0xfffffffc,%eax
  mov    -0x54(%rbp),%ebx
  cmp    %ebx,%eax
  cmovg  %ebx,%eax
  mov    %eax,-0x58(%rbp)
  imul   0x10(%rbp),%eax
  add    $0x3,%eax
  cltq
  lea    0xf(,%rax,8),%rdx
  mov    %rdx,%rax
  and    $0xfffffffffffffff0,%rax
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rcx
  sub    %rdx,%rcx
L193:
  cmp    %rcx,%rsp
  je     L87
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L193
L11:
  cmpl   $0x2,0x10(%rbp)
  sete   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  mov    -0x64(%rbp),%r8d
  mov    -0x54(%rbp),%ecx
  mov    -0x70(%rbp),%rdx
  mov    -0x60(%rbp),%rsi
  mov    -0x98(%rbp),%rdi
  call   <matprod_trans12_m2@plt>
  mov    -0x90(%rbp),%rsp
  jmp    L241
L87:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L176
  orq    $0x0,-0x8(%rsp,%rdx,1)
L176:
  mov    %rsp,%r12
  cmpl   $0x0,0x10(%rbp)
  jle    L117
  mov    0x10(%rbp),%eax
  mov    %eax,-0x84(%rbp)
L268:
  movslq -0x64(%rbp),%rax
  mov    %rax,-0x78(%rbp)
  movslq -0x54(%rbp),%rax
  lea    0x0(,%rax,8),%r14
  movl   $0x0,-0x80(%rbp)
  mov    -0x84(%rbp),%eax
  mov    %eax,-0x9c(%rbp)
  mov    -0x58(%rbp),%eax
  mov    %eax,-0x88(%rbp)
  lea    0x8(%r12),%r15
  jmp    L140
L14:
  mov    -0x9c(%rbp),%ebx
  jmp    L206
L86:
  mov    -0x88(%rbp),%r13d
  jmp    L259
L51:
  movslq %edi,%rdx
  lea    (%r12,%rdx,8),%rax
  add    %r10,%rdx
  lea    (%r15,%rdx,8),%rcx
  mov    %r8,%rdx
L274:
  movsd  (%rax),%xmm0
  movsd  %xmm0,(%rdx)
  add    $0x8,%rax
  add    %r14,%rdx
  cmp    %rcx,%rax
  jne    L274
L179:
  add    $0x8,%r8
  add    -0x44(%rbp),%edi
  add    $0x1,%rsi
  cmp    %r9,%rsi
  je     L70
L0:
  test   %ebx,%ebx
  jg     L51
  jmp    L179
L70:
  movslq %r13d,%rax
  imul   -0x78(%rbp),%rax
  mov    -0x50(%rbp),%rsi
  lea    (%rsi,%rax,8),%rax
  mov    %rax,-0x50(%rbp)
  add    %r13d,-0x48(%rbp)
  mov    -0x48(%rbp),%eax
  cmp    %eax,-0x54(%rbp)
  jle    L240
L162:
  mov    -0x54(%rbp),%r13d
  sub    -0x48(%rbp),%r13d
  mov    -0x58(%rbp),%edi
  cmp    %r13d,%edi
  jge    L259
  mov    %r13d,%eax
  sub    %edi,%eax
  cmp    $0x2,%eax
  jg     L86
  mov    %r13d,%eax
  shr    $0x1f,%eax
  add    %r13d,%eax
  sar    %eax
  mov    %eax,%r13d
L259:
  push   %rbx
  push   %rbx
  mov    %r13d,%r9d
  mov    -0x64(%rbp),%r8d
  mov    -0x68(%rbp),%ecx
  mov    %r12,%rdx
  mov    -0x50(%rbp),%rsi
  mov    -0x60(%rbp),%rdi
  call   <matprod_mat_mat_sub_xrows@plt>
  add    $0x10,%rsp
  test   %r13d,%r13d
  jle    L70
  movslq -0x48(%rbp),%rsi
  mov    -0x70(%rbp),%rax
  lea    (%rax,%rsi,8),%r8
  lea    -0x1(%r13),%eax
  lea    0x1(%rsi,%rax,1),%r9
  mov    $0x0,%edi
  mov    -0x7c(%rbp),%r10d
  jmp    L0
L240:
  movslq %ebx,%rax
  mov    -0x60(%rbp),%rsi
  lea    (%rsi,%rax,8),%rsi
  mov    %rsi,-0x60(%rbp)
  imul   %r14,%rax
  add    %rax,-0x70(%rbp)
  add    %ebx,-0x80(%rbp)
  mov    -0x80(%rbp),%eax
  cmp    %eax,0x10(%rbp)
  jle    L117
L140:
  mov    0x10(%rbp),%ebx
  sub    -0x80(%rbp),%ebx
  mov    -0x84(%rbp),%esi
  cmp    %ebx,%esi
  jge    L206
  mov    %ebx,%eax
  sub    %esi,%eax
  cmp    $0x2,%eax
  jg     L14
  mov    %ebx,%eax
  shr    $0x1f,%eax
  add    %ebx,%eax
  sar    %eax
  and    $0xfffffffc,%eax
  mov    %eax,%ebx
L206:
  cmpl   $0x0,-0x54(%rbp)
  jle    L240
  mov    -0x98(%rbp),%rax
  mov    %rax,-0x50(%rbp)
  movl   $0x0,-0x48(%rbp)
  mov    %ebx,%eax
  mov    %ebx,-0x44(%rbp)
  sub    $0x1,%eax
  mov    %eax,-0x7c(%rbp)
  jmp    L162
L117:
  mov    -0x90(%rbp),%rsp
L241:
  mov    -0x38(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L239
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L219:
  mov    $0x10,%eax
  mov    -0x54(%rbp),%ebx
  cmp    %eax,%ebx
  cmovle %ebx,%eax
  mov    %eax,-0x58(%rbp)
  shl    $0x7,%eax
  add    $0x3,%eax
  cltq
  lea    0xf(,%rax,8),%rdx
  mov    %rdx,%rax
  and    $0xfffffffffffffff0,%rax
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rcx
  sub    %rdx,%rcx
L186:
  cmp    %rcx,%rsp
  je     L57
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L186
L57:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L15
  orq    $0x0,-0x8(%rsp,%rdx,1)
L15:
  mov    %rsp,%r12
  movl   $0x80,-0x84(%rbp)
  jmp    L268
L239:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void matprod_trans12_sub(double *restrict x, double *restrict y, double *restrict z, int n, int k, int m, int zcols) {
  assert(((uintptr_t)(x) & (1 - 1)) == 0);
  assert(((uintptr_t)(y) & (1 - 1)) == 0);
  assert(((uintptr_t)(z) & (1 - 1)) == 0);
  x = (x);
  y = (y);
  z = (z);
  assert(m >= 2);
  assert(k >= 2);
  assert(n >= 2);
  assert(zcols >= 2);
  if (m == 2) {
    assert(zcols == 2);
    matprod_trans12_m2(x, y, z, n, k);
    return;
  }
  int zr, zc;
  zc = 128;
  if (zc > zcols) {
    zc = zcols;
  }
  zr = (2048 / zc) & ~3;
  if (zr > n) {
    zr = n;
  }
  double zelem[zr * zc + 3];
  double *ztmp = zelem;
  while ((((uintptr_t)ztmp) & (1 - 1)) != 0) {
    ztmp += 1;
  }
  int j = 0;
  while (j < zcols) {
    int remaining_cols = zcols - j;
    int zzc = remaining_cols <= zc ? remaining_cols : remaining_cols - zc < 3 ? (remaining_cols / 2) & ~3 : zc;
    double *xx = x;
    int i = 0;
    while (i < n) {
      int remaining_rows = n - i;
      int zzr = remaining_rows <= zr ? remaining_rows : remaining_rows - zr < 3 ? remaining_rows / 2 : zr;
      matprod_mat_mat_sub_xrows(y, xx, ztmp, m, k, zzr, zzc, zzc);
      int ii, jj;
      for (ii = 0; ii < zzr; ii++) {
        for (jj = 0; jj < zzc; jj++) {
          z[i + ii + (size_t)jj * n] = ztmp[jj + ii * zzc];
        }
      }
      xx += (size_t)zzr * k;
      i += zzr;
    }
    y += zzc;
    z += (size_t)zzc * n;
    j += zzc;
  }
}
```