user: 请从给定的汇编指令推导出C源代码：

```asm
<gauss>:
  endbr64
  push   %r15
  movslq %ecx,%rax
  push   %r14
  mov    %r8d,%r14d
  push   %r13
  push   %r12
  mov    %rax,%r12
  push   %rbp
  push   %rbx
  mov    %edx,%ebx
  sub    $0x68,%rsp
  mov    %rdi,0x28(%rsp)
  lea    0x0(,%rax,4),%edi
  mov    %rsi,0x50(%rsp)
  mov    %edx,0x1c(%rsp)
  mov    %rax,0x58(%rsp)
  call   <malloc@plt>
  mov    %rax,0x40(%rsp)
  lea    -0x1(%r12),%eax
  mov    %eax,0x4c(%rsp)
  test   %ebx,%ebx
  jle    L310
  test   %eax,%eax
  jle    L122
  lea    -0x2(%r12),%eax
  mov    %r12d,0x30(%rsp)
  xor    %r15d,%r15d
  xor    %ebx,%ebx
  mov    %rax,0x38(%rsp)
  mov    %r15d,%edi
  mov    %r14d,%ebp
  mov    %r12d,%r15d
  movq   $0x0,0x20(%rsp)
L303:
  mov    0x20(%rsp),%rax
  mov    0x1c(%rsp),%esi
  mov    %ebx,0x48(%rsp)
  lea    0x0(,%rbx,4),%r13
  lea    0x0(,%rax,8),%r10
  mov    0x28(%rsp),%rax
  add    %r10,%rax
  mov    %rax,0x8(%rsp)
  mov    %rax,%rdx
  mov    %edi,%eax
  nop
L152:
  mov    (%rdx),%rcx
  mov    (%rcx,%r13,1),%ecx
  test   %ecx,%ecx
  je     L84
  cmp    $0xffffffff,%eax
  je     L304
  mov    0x8(%rsp),%rsi
  mov    %ebx,0x18(%rsp)
  mov    (%rsi),%r11
  cmp    %r15d,%ebx
  jge    L123
  mov    0x28(%rsp),%rsi
  cltq
  lea    (%r11,%r13,1),%r12
  mov    (%rsi,%rax,8),%rcx
  lea    0x10(%r13),%rax
  lea    (%r11,%rax,1),%r14
  lea    (%rcx,%r13,1),%rdx
  cmp    %r14,%rdx
  setae  %r14b
  add    %rcx,%rax
  cmp    %rax,%r12
  setae  %al
  or     %r14b,%al
  je     L137
  mov    0x30(%rsp),%esi
  cmp    $0x1,%esi
  je     L137
  lea    -0x1(%rsi),%eax
  cmp    $0x2,%eax
  jbe    L156
  shr    $0x2,%esi
  xor    %eax,%eax
  mov    %esi,%r14d
  shl    $0x4,%r14
  cs nopw 0x0(%rax,%rax,1)
L321:
  movdqu (%r12,%rax,1),%xmm0
  movdqu (%rdx,%rax,1),%xmm2
  movups %xmm2,(%r12,%rax,1)
  movups %xmm0,(%rdx,%rax,1)
  add    $0x10,%rax
  cmp    %r14,%rax
  jne    L321
  mov    0x30(%rsp),%esi
  mov    0x48(%rsp),%eax
  mov    %esi,%edx
  and    $0xfffffffc,%edx
  add    %edx,%eax
  cmp    %esi,%edx
  je     L123
  sub    %edx,%esi
  mov    %esi,%r12d
  cmp    $0x1,%esi
  je     L327
L43:
  add    %rbx,%rdx
  shl    $0x2,%rdx
  lea    (%r11,%rdx,1),%r14
  add    %rcx,%rdx
  movq   (%rdx),%xmm1
  movq   (%r14),%xmm0
  movq   %xmm1,(%r14)
  movq   %xmm0,(%rdx)
  mov    %r12d,%edx
  and    $0xfffffffe,%edx
  add    %edx,%eax
  cmp    %r12d,%edx
  je     L123
L327:
  cltq
  shl    $0x2,%rax
  lea    (%r11,%rax,1),%rdx
  add    %rcx,%rax
  mov    (%rdx),%r12d
  mov    (%rax),%ecx
  mov    %ecx,(%rdx)
  mov    %r12d,(%rax)
L123:
  lea    0x1(%rdi),%eax
  mov    %eax,0x34(%rsp)
  cmp    %eax,0x1c(%rsp)
  jle    L105
  mov    0x1c(%rsp),%eax
  mov    0x28(%rsp),%rsi
  sub    $0x2,%eax
  lea    0x8(%rsi,%r10,1),%r12
  sub    %edi,%eax
  add    0x20(%rsp),%rax
  mov    %r12,%r14
  mov    %r13,%r12
  lea    0x10(%rsi,%rax,8),%rax
  mov    %ebp,%r13d
  mov    %rbx,%rbp
  mov    %r15d,%ebx
  mov    %rax,0x10(%rsp)
L58:
  mov    (%r14),%rax
  mov    (%r11,%r12,1),%edi
  mov    %r13d,%esi
  mov    (%rax,%r12,1),%r15d
  call   <invMod@plt>
  neg    %r15d
  imul   %r15d,%eax
  cltd
  idiv   %r13d
  mov    %edx,%edi
  cmp    %ebx,0x18(%rsp)
  jge    L214
  mov    0x8(%rsp),%rax
  mov    (%r14),%rsi
  mov    %rbp,%rcx
  mov    (%rax),%r11
  nopl   0x0(%rax,%rax,1)
L17:
  mov    (%r11,%rcx,4),%eax
  imul   %edi,%eax
  add    (%rsi,%rcx,4),%eax
  cltd
  idiv   %r13d
  mov    %edx,(%rsi,%rcx,4)
  add    $0x1,%rcx
  cmp    %ecx,%ebx
  jg     L17
  add    $0x8,%r14
  cmp    %r14,0x10(%rsp)
  jne    L58
L50:
  mov    %ebx,%r15d
  mov    %rbp,%rbx
  mov    %r13d,%ebp
  mov    %r12,%r13
L105:
  mov    (%r11,%r13,1),%edi
  mov    %ebp,%esi
  call   <invMod@plt>
  mov    %eax,%ecx
  cmp    %r15d,0x18(%rsp)
  jge    L410
  mov    0x30(%rsp),%edi
  mov    0x8(%rsp),%rax
  lea    -0x1(%rdi),%edx
  mov    (%rax),%rax
  lea    0x1(%rbx,%rdx,1),%rdx
  lea    (%rax,%r13,1),%r9
  lea    (%rax,%rdx,4),%rdi
L188:
  mov    (%r9),%eax
  add    $0x4,%r9
  imul   %ecx,%eax
  cltd
  idiv   %ebp
  mov    %edx,-0x4(%r9)
  cmp    %r9,%rdi
  jne    L188
L410:
  mov    0x20(%rsp),%rdi
  mov    0x40(%rsp),%rax
  mov    0x48(%rsp),%esi
  mov    %esi,(%rax,%rdi,4)
  mov    0x34(%rsp),%edi
  cmp    %edi,0x1c(%rsp)
  jle    L35
  cmp    0x38(%rsp),%rbx
  je     L323
  movslq %edi,%rax
  subl   $0x1,0x30(%rsp)
  add    $0x1,%rbx
  mov    %rax,0x20(%rsp)
  jmp    L303
  cs nopw 0x0(%rax,%rax,1)
L84:
  add    $0x1,%eax
  add    $0x8,%rdx
  cmp    %eax,%esi
  jg     L152
L304:
  cmp    0x38(%rsp),%rbx
  je     L89
  subl   $0x1,0x30(%rsp)
  add    $0x1,%rbx
  cmp    %edi,0x1c(%rsp)
  jg     L303
  mov    %r15d,%r12d
  mov    %ebp,%r14d
  mov    %edi,%r15d
L373:
  lea    -0x1(%r15),%ebx
L174:
  mov    0x58(%rsp),%rax
  mov    0x28(%rsp),%rsi
  mov    0x50(%rsp),%rdi
  mov    0x20(%rsp),%r8
  lea    -0x4(,%rax,4),%rcx
  xor    %eax,%eax
  nopl   0x0(%rax,%rax,1)
L284:
  mov    (%rsi,%rax,8),%rdx
  mov    (%rdx,%rcx,1),%edx
  mov    %edx,(%rdi,%rax,4)
  add    $0x1,%rax
  cmp    %rax,%r8
  jne    L284
  cmp    0x4c(%rsp),%r15d
  jge    L395
L268:
  lea    -0x2(%r12),%eax
  mov    0x20(%rsp),%rdi
  sub    %r15d,%eax
  lea    0x4(,%rax,4),%rdx
  lea    0x1(%r15),%eax
  cmp    %eax,%r12d
  mov    $0x4,%eax
  cmovle %rax,%rdx
  mov    0x50(%rsp),%rax
  xor    %esi,%esi
  lea    (%rax,%rdi,4),%rdi
  call   <memset@plt>
L249:
  cmp    $0xffffffff,%ebx
  je     L69
L395:
  mov    0x50(%rsp),%r10
  mov    0x40(%rsp),%r9
  movslq %ebx,%rdi
  mov    0x4c(%rsp),%r8d
  mov    0x28(%rsp),%r11
  lea    (%r10,%rdi,4),%rsi
  sub    %r10,%r9
  nopw   0x0(%rax,%rax,1)
L65:
  mov    (%r9,%rsi,1),%eax
  lea    0x1(%rax),%edx
  mov    (%rsi),%eax
  cmp    %r8d,%edx
  jge    L232
  mov    (%r11,%rdi,8),%rbx
  movslq %edx,%rdx
  nopl   (%rax)
L146:
  mov    (%rbx,%rdx,4),%ecx
  imul   (%r10,%rdx,4),%ecx
  add    $0x1,%rdx
  sub    %ecx,%eax
  mov    %eax,(%rsi)
  cmp    %edx,%r8d
  jg     L146
L232:
  cltd
  sub    $0x1,%rdi
  sub    $0x4,%rsi
  idiv   %r14d
  lea    (%rdx,%r14,1),%eax
  cltd
  idiv   %r14d
  mov    %edx,0x4(%rsi)
  test   %edi,%edi
  jns    L65
L69:
  mov    0x40(%rsp),%rdi
  call   <free@plt>
  add    $0x68,%rsp
  mov    $0x1,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  xchg   %ax,%ax
L214:
  mov    0x8(%rsp),%rax
  add    $0x8,%r14
  mov    (%rax),%r11
  cmp    %r14,0x10(%rsp)
  jne    L58
  jmp    L50
L137:
  mov    %rbx,%rax
  nop
L238:
  mov    (%r11,%rax,4),%edx
  mov    (%rcx,%rax,4),%esi
  mov    %esi,(%r11,%rax,4)
  mov    %edx,(%rcx,%rax,4)
  add    $0x1,%rax
  cmp    %eax,%r15d
  jg     L238
  jmp    L123
L156:
  mov    0x48(%rsp),%eax
  mov    %esi,%r12d
  xor    %edx,%edx
  jmp    L43
L323:
  mov    %r15d,%r12d
  mov    %ebp,%r14d
L267:
  mov    0x58(%rsp),%rax
  mov    0x28(%rsp),%rsi
  mov    0x1c(%rsp),%edi
  lea    -0x4(,%rax,4),%rcx
  movslq 0x34(%rsp),%rax
  jmp    L195
  nopl   (%rax)
L221:
  add    $0x1,%rax
  cmp    %eax,%edi
  jle    L337
L195:
  mov    (%rsi,%rax,8),%rdx
  mov    (%rdx,%rcx,1),%edx
  test   %edx,%edx
  je     L221
  mov    0x40(%rsp),%rdi
  call   <free@plt>
  add    $0x68,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L89:
  mov    %edi,0x34(%rsp)
  mov    %r15d,%r12d
  mov    %ebp,%r14d
  jmp    L267
L310:
  mov    $0xffffffff,%ebx
L432:
  mov    0x4c(%rsp),%eax
  test   %eax,%eax
  jle    L249
  movq   $0x0,0x20(%rsp)
  xor    %r15d,%r15d
  jmp    L268
L122:
  movl   $0x0,0x34(%rsp)
  jmp    L267
L337:
  mov    0x34(%rsp),%eax
  lea    -0x1(%rax),%ebx
  test   %eax,%eax
  je     L432
  movslq 0x34(%rsp),%rax
  mov    %rax,0x20(%rsp)
  mov    %rax,%r15
  jmp    L174
L35:
  movslq %edi,%rax
  mov    %r15d,%r12d
  mov    %ebp,%r14d
  mov    %rax,0x20(%rsp)
  mov    %rax,%r15
  jmp    L373
```

assistant: ```c
int gauss(int **a, int *x, int m, int n, int q) {
  int rank = 0, i, j, k, l, *pivot = (int *)malloc(sizeof(int) * n);
  for (i = 0, j = 0; i < m && j < n - 1; ++j) {
    int p = -1, tmp = 0;
    for (k = i; p < 0 && k < m; ++k) {
      if (a[k][j] != 0)
        p = k;
    }
    if (p == -1)
      continue;
    for (k = j; k < n; ++k)
      tmp = a[i][k], a[i][k] = a[p][k], a[p][k] = tmp;
    for (k = i + 1; k < m; ++k) {
      tmp = -a[k][j] * invMod(a[i][j], q) % q;
      for (l = j; l < n; ++l)
        a[k][l] = (a[k][l] + tmp * a[i][l]) % q;
    }
    tmp = invMod(a[i][j], q);
    for (k = j; k < n; ++k)
      a[i][k] = a[i][k] * tmp % q;
    pivot[i++] = j, rank++;
  }
  for (i = rank; i < m; ++i)
    if (a[i][n - 1] != 0) {
      free(pivot);
      return 0;
    }
  for (i = 0; i < rank; ++i)
    x[i] = a[i][n - 1];
  for (i = rank; i < n - 1; ++i)
    x[i] = 0;
  for (i = rank - 1; i >= 0; --i) {
    for (j = pivot[i] + 1; j < n - 1; ++j)
      x[i] -= a[i][j] * x[j];
    x[i] -= x[i] / q * q, x[i] = (x[i] + q) % q;
  }
  free(pivot);
  return 1;
}
```