Re: [PATCH v4] H8/300: sim: Fix simulator hang caused by qsort on Windows/MinGW

[Simon Marchi <simark@simark.ca>]

On 9/9/26 9:58 PM, Jan Dubiec wrote:
> On Windows, qsort() uses an unstable sorting algorithm, which results
> in a "shuffled" opcode table rather than a properly sorted one, causing
> the entire simulator to hang.
> 
> The simulator happens to work on Linux, but this behavior is not
> guaranteed, because the glibc documentation clearly states that "If
> two elements compare equal, their order after sorting is unpredictable."
> 
> This patch introduces two additional sort keys to the instruction
> comparator function, making the resulting opcode table as close as
> possible to the one that would be produced by a stable sorting algorithm.
> 
> It also fixes an issue in the instruction decoder where, for example,
> mov.l @er7+,er1 is recognized as ldm.l @er7+,(er0-er1) if the opcode
> table is sorted �the wrong way�, i.e. when ldm appears before mov

The characters around "the wrong way" seem to suffer from bad encoding.

> @@ -1605,7 +1614,45 @@ instruction_comparator (const void *p1_, const void *p2_)
>      return p2_available - p1_available;
>  
>    /* Secondarily sort based on the first opcode nibble.  */
> -  return p1->data.nib[0] - p2->data.nib[0];
> +  if (p1->data.nib[0] != p2->data.nib[0])
> +    return p1->data.nib[0] - p2->data.nib[0];
> +
> +  /* The 3rd sort key  */
> +  cmp = strcmp (p1->name, p2->name);
> +  if (cmp)
> +    {
> +      /* Two different opcodes  */
> +      size_t l1 = strlen (p1->name);
> +      size_t l2 = strlen (p2->name);
> +      ptrdiff_t i1 = strchr (p1->name, '.') - p1->name;
> +      ptrdiff_t i2 = strchr (p2->name, '.') - p2->name;
> +      char c1, c2;
> +
> +      if ((l1 == l2) && (i1 == i2) && (i1 > 0))
> +	{
> +	  /* Check for different mnemonics of the same length,
> +	     e.g. add.w vs. and.b  */
> +	  cmp = strncmp (p1->name, p2->name, i1);
> +	  if (cmp)
> +	    return cmp;
> +
> +	  /* At this point we expect only b, w or l suffix,
> +	     where b < w < l  */
> +	  c1 = p1->name[i1+1];
> +	  c2 = p2->name[i2+1];
> +	  if (c1 == 'b')
> +	    return -1;
> +	  else if (c1 == 'w')
> +	    return (c2 == 'b') ? 1 : -1;
> +	  else
> +	    return 1;
> +	}
> +
> +      return cmp;
> +    }
> +
> +  /* The 4th sort key  */
> +  return p1->how - p2->how;

I'd suggest using a

  SIM_ASSERT (p1->how != p2->how)

above, since we never want two entries to compare equal.

Otherwise, I don't have enought knowledge about this architecture to
really review the patch.

Simon