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

```asm
<pencil_dsyr2k_nn_u>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  mov    %edi,-0x54(%rbp)
  mov    %esi,-0x58(%rbp)
  movsd  %xmm0,-0x60(%rbp)
  mov    %edx,-0x64(%rbp)
  mov    %rcx,-0x70(%rbp)
  mov    %r8d,-0x68(%rbp)
  mov    %r9,-0x78(%rbp)
  movsd  %xmm1,-0x80(%rbp)
  mov    -0x58(%rbp),%eax
  movslq %eax,%rdx
  sub    $0x1,%rdx
  mov    %rdx,-0x38(%rbp)
  movslq %eax,%rdx
  mov    %rdx,%r14
  mov    $0x0,%r15d
  mov    -0x54(%rbp),%edx
  movslq %edx,%rcx
  sub    $0x1,%rcx
  mov    %rcx,-0x30(%rbp)
  movslq %edx,%rcx
  mov    %rcx,%r12
  mov    $0x0,%r13d
  mov    -0x54(%rbp),%ecx
  movslq %ecx,%rsi
  sub    $0x1,%rsi
  mov    %rsi,-0x28(%rbp)
  movslq %ecx,%rsi
  mov    %rsi,%r10
  mov    $0x0,%r11d
  movl   $0x0,-0x4c(%rbp)
  jmp    L31
L7:
  movl   $0x0,-0x48(%rbp)
  jmp    L1
L54:
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x40(%rbp)
  movl   $0x0,-0x44(%rbp)
  jmp    L53
L6:
  mov    -0x4c(%rbp),%esi
  movslq %esi,%rdi
  movslq %eax,%rsi
  imul   %rdi,%rsi
  lea    0x0(,%rsi,8),%rdi
  mov    -0x70(%rbp),%rsi
  add    %rsi,%rdi
  mov    -0x44(%rbp),%esi
  movslq %esi,%rsi
  movsd  (%rdi,%rsi,8),%xmm1
  mov    -0x48(%rbp),%edi
  mov    -0x4c(%rbp),%esi
  add    %edi,%esi
  movslq %esi,%rdi
  movslq %edx,%rsi
  imul   %rdi,%rsi
  lea    0x0(,%rsi,8),%rdi
  mov    -0x78(%rbp),%rsi
  add    %rsi,%rdi
  mov    -0x44(%rbp),%esi
  movslq %esi,%rsi
  movsd  (%rdi,%rsi,8),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x4c(%rbp),%esi
  movslq %esi,%rdi
  movslq %edx,%rsi
  imul   %rdi,%rsi
  lea    0x0(,%rsi,8),%rdi
  mov    -0x78(%rbp),%rsi
  add    %rsi,%rdi
  mov    -0x44(%rbp),%esi
  movslq %esi,%rsi
  movsd  (%rdi,%rsi,8),%xmm2
  mov    -0x48(%rbp),%edi
  mov    -0x4c(%rbp),%esi
  add    %edi,%esi
  movslq %esi,%rdi
  movslq %eax,%rsi
  imul   %rdi,%rsi
  lea    0x0(,%rsi,8),%rdi
  mov    -0x70(%rbp),%rsi
  add    %rsi,%rdi
  mov    -0x44(%rbp),%esi
  movslq %esi,%rsi
  movsd  (%rdi,%rsi,8),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm1,%xmm0
  movsd  -0x40(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x40(%rbp)
  addl   $0x1,-0x44(%rbp)
L53:
  mov    -0x58(%rbp),%esi
  cmp    -0x44(%rbp),%esi
  jg     L6
  mov    -0x4c(%rbp),%esi
  movslq %esi,%rdi
  movslq %ecx,%rsi
  imul   %rdi,%rsi
  lea    0x0(,%rsi,8),%rdi
  mov    0x18(%rbp),%rsi
  add    %rsi,%rdi
  mov    -0x4c(%rbp),%r8d
  mov    -0x48(%rbp),%esi
  add    %r8d,%esi
  movslq %esi,%rsi
  movsd  (%rdi,%rsi,8),%xmm0
  movapd %xmm0,%xmm1
  mulsd  -0x80(%rbp),%xmm1
  movsd  -0x60(%rbp),%xmm0
  mulsd  -0x40(%rbp),%xmm0
  mov    -0x4c(%rbp),%esi
  movslq %esi,%rdi
  movslq %ecx,%rsi
  imul   %rdi,%rsi
  lea    0x0(,%rsi,8),%rdi
  mov    0x18(%rbp),%rsi
  add    %rsi,%rdi
  mov    -0x4c(%rbp),%r8d
  mov    -0x48(%rbp),%esi
  add    %r8d,%esi
  addsd  %xmm1,%xmm0
  movslq %esi,%rsi
  movsd  %xmm0,(%rdi,%rsi,8)
  addl   $0x1,-0x48(%rbp)
L1:
  mov    -0x54(%rbp),%esi
  sub    $0x1,%esi
  sub    -0x4c(%rbp),%esi
  cmp    %esi,-0x48(%rbp)
  jle    L54
  addl   $0x1,-0x4c(%rbp)
L31:
  mov    -0x54(%rbp),%esi
  cmp    -0x4c(%rbp),%esi
  jg     L7
  nop
  nop
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
```

assistant: ```c
void pencil_dsyr2k_nn_u(int n_255_607, int k_256_608, double alpha_257_609, int ldA_258_610, double A_259_611[restrict const n_255_607][k_256_608], int ldB_260_612, double B_261_613[restrict const k_256_608][n_255_607], double beta_262_614, int ldCT_263_615, double CT_264_616[restrict const n_255_607][n_255_607]) {
#pragma scop
  {
#pragma pencil independent
    for (int i_323_273_1243_2069 = 0; i_323_273_1243_2069 <= (n_255_607 - 1); i_323_273_1243_2069 += 1) {
#pragma pencil independent
      for (int i_325_275_1244_2071 = 0; i_325_275_1244_2071 <= ((((n_255_607 - 1) - i_323_273_1243_2069) + 1) - 1); i_325_275_1244_2071 += 1) {
        double accum_326_276_1245_2068;
        accum_326_276_1245_2068 = 0.0;
        for (int i_327_277_1246_2070 = 0; i_327_277_1246_2070 <= (k_256_608 - 1); i_327_277_1246_2070 += 1) {
          accum_326_276_1245_2068 = (accum_326_276_1245_2068 + ((A_259_611[i_323_273_1243_2069][i_327_277_1246_2070] * B_261_613[(i_325_275_1244_2071 + i_323_273_1243_2069)][i_327_277_1246_2070]) + (B_261_613[i_323_273_1243_2069][i_327_277_1246_2070] * A_259_611[(i_325_275_1244_2071 + i_323_273_1243_2069)][i_327_277_1246_2070])));
        }
        CT_264_616[i_323_273_1243_2069][(i_323_273_1243_2069 + i_325_275_1244_2071)] = ((beta_262_614 * CT_264_616[i_323_273_1243_2069][(i_323_273_1243_2069 + i_325_275_1244_2071)]) + (alpha_257_609 * accum_326_276_1245_2068));
      }
    }
  }
#pragma endscop
}
```