user: Please show me the C implementation that matches the assembly code listed below:

```asm
<dtrans_mat_mat_mult>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x58,%rsp
  mov    %rdi,0x40(%rsp)
  mov    %edx,0x28(%rsp)
  mov    %ecx,0x24(%rsp)
  test   %ecx,%ecx
  jle    L6
  lea    -0x1(%rcx),%eax
  mov    %ecx,%ebx
  mov    %rsi,%r13
  xor    %r15d,%r15d
  and    $0xffffffe0,%eax
  shl    $0x5,%ebx
  add    $0x20,%eax
  mov    %ebx,0x3c(%rsp)
  mov    %eax,0x48(%rsp)
  movslq %ecx,%rax
  mov    %rax,0x8(%rsp)
  lea    0x0(,%rax,8),%r14
L133:
  mov    0x24(%rsp),%eax
  lea    0x1f(%r15),%r12d
  lea    0x20(%r15),%ebp
  mov    %ebp,0x34(%rsp)
  cmp    %r12d,%eax
  mov    %r12d,0x14(%rsp)
  cmovle %eax,%ebp
  xor    %ebx,%ebx
  xor    %eax,%eax
  mov    %ebp,%r12d
  mov    %rbx,%rbp
  mov    %eax,%ebx
L52:
  cmp    %ebx,%r15d
  movslq %ebx,%rax
  mov    %r12d,%edx
  cmovge %r15,%rax
  xor    %edi,%edi
  sub    %eax,%edx
  shl    $0x3,%rdx
  cmp    %eax,%r12d
  cmovl  %rdi,%rdx
  add    %rbp,%rax
  xor    %esi,%esi
  lea    0x0(%r13,%rax,8),%rdi
  call   <memset@plt>
  mov    %ebx,0x38(%rsp)
  add    $0x1,%ebx
  pxor   %xmm2,%xmm2
  add    0x8(%rsp),%rbp
  cmp    %ebx,0x24(%rsp)
  jne    L52
  mov    0x28(%rsp),%eax
  mov    0x14(%rsp),%r12d
  mov    %ebx,0x2c(%rsp)
  test   %eax,%eax
  jle    L86
  mov    0x24(%rsp),%eax
  mov    0x34(%rsp),%ebx
  movl   $0x0,0x30(%rsp)
  cmp    %r12d,%eax
  mov    %rax,0x18(%rsp)
  cmovle %eax,%ebx
  xor    %r10d,%r10d
  lea    -0x1(%rbx),%eax
  mov    %ebx,0x14(%rsp)
  mov    %eax,0x20(%rsp)
L99:
  mov    0x28(%rsp),%ebx
  lea    0x1f(%r10),%eax
  lea    0x20(%r10),%edi
  mov    %edi,0x4c(%rsp)
  cmp    %eax,%ebx
  movslq 0x30(%rsp),%rax
  cmovle %ebx,%edi
  mov    0x40(%rsp),%rbx
  xor    %r12d,%r12d
  xor    %ebp,%ebp
  lea    (%rbx,%rax,8),%rbx
  nopl   0x0(%rax)
L16:
  mov    %ebp,%eax
  cmp    %ebp,%r15d
  lea    0x0(,%rbp,8),%r8
  cmovge %r15d,%eax
  cmp    %eax,0x14(%rsp)
  jle    L51
  mov    0x20(%rsp),%ecx
  movslq %eax,%rdx
  lea    0x0(%r13,%r12,8),%r9
  lea    0x0(,%rdx,8),%rsi
  sub    %eax,%ecx
  lea    0x1(%rdx,%rcx,1),%r11
  shl    $0x3,%r11
  xchg   %ax,%ax
L61:
  mov    %rbx,%rax
  mov    %r10d,%edx
  movapd %xmm2,%xmm1
  cmp    %r10d,%edi
  jle    L123
  nop
L48:
  mov    %rax,%rcx
  add    $0x1,%edx
  sub    %r8,%rcx
  movsd  (%rcx,%rsi,1),%xmm0
  mulsd  (%rax),%xmm0
  add    %r14,%rax
  addsd  %xmm0,%xmm1
  cmp    %edx,%edi
  jne    L48
L123:
  addsd  (%r9,%rsi,1),%xmm1
  movsd  %xmm1,(%r9,%rsi,1)
  add    $0x8,%rsi
  cmp    %r11,%rsi
  jne    L61
L51:
  add    $0x1,%rbp
  add    0x8(%rsp),%r12
  add    $0x8,%rbx
  cmp    0x18(%rsp),%rbp
  jne    L16
  mov    0x3c(%rsp),%ebx
  mov    0x4c(%rsp),%r10d
  add    %ebx,0x30(%rsp)
  cmp    %r10d,0x28(%rsp)
  jg     L99
L86:
  movslq 0x34(%rsp),%r15
  cmp    0x48(%rsp),%r15d
  jne    L133
  cmpl   $0x1,0x2c(%rsp)
  je     L6
  movslq 0x2c(%rsp),%rax
  lea    0x8(%r13),%rsi
  lea    0x0(%r13,%rax,8),%rcx
  mov    $0x1,%eax
L136:
  mov    %rsi,%rdi
  xor    %edx,%edx
L18:
  movsd  (%rdi),%xmm0
  add    %r14,%rdi
  movsd  %xmm0,(%rcx,%rdx,8)
  add    $0x1,%rdx
  cmp    %edx,%eax
  jg     L18
  lea    0x1(%rax),%edx
  add    $0x8,%rsi
  add    %r14,%rcx
  cmp    0x38(%rsp),%eax
  je     L6
  mov    %edx,%eax
  jmp    L136
L6:
  add    $0x58,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void dtrans_mat_mat_mult(double *a, double *b, int n, int m) {
  register int i, j, k, jj, kk;
  register double sum, *bim, *akm;
  const int bsize = 32;
  for (jj = 0; jj < m; jj += bsize) {
    for (i = 0; i < m; ++i) {
      bim = b + i * m;
      for (j = (((jj) >= (i)) ? (jj) : (i)); j < (((jj + bsize) <= (m)) ? (jj + bsize) : (m)); ++j)
        bim[j] = 0.0;
    }
    for (kk = 0; kk < n; kk += bsize) {
      for (i = 0; i < m; ++i) {
        bim = b + i * m;
        for (j = (((jj) >= (i)) ? (jj) : (i)); j < (((jj + bsize) <= (m)) ? (jj + bsize) : (m)); ++j) {
          sum = 0.0;
          for (k = kk; k < (((kk + bsize) <= (n)) ? (kk + bsize) : (n)); ++k) {
            akm = a + k * m;
            sum += akm[i] * akm[j];
          }
          bim[j] += sum;
        }
      }
    }
  }
  for (i = 0; i < m; ++i)
    for (j = 0; j < i; ++j)
      b[i * m + j] = b[j * m + i];
}
```