[PATCH] opcodes: i386: fix dw2_regnum data type in reg_entry

[Jan Beulich]

On 09.01.2024 02:12, Indu Bhagat wrote:
> The DWARF register numbers for the APX EGRPs start with 130.  The data
> type holding the same currently is signed char.
> 
> ChangeLog:
> 	* opcodes/i386-opc.h (reg_entry): Bump to signed short.

So yes, something needs doing. But there are further questions to be
raised to the original authors: Was the code tested at all in this
regard? Why do numbers start at 130, when according to i386-reg.tbl
128 and 129 are unused (and would hence be more natural to [also]
use)?

> --- a/opcodes/i386-opc.h
> +++ b/opcodes/i386-opc.h
> @@ -1047,7 +1047,7 @@ typedef struct
>  #define RegIZ	(RegIP - 1)
>  /* FLAT is a fake segment register (Intel mode).  */
>  #define RegFlat     ((unsigned char) ~0)
> -  signed char dw2_regnum[2];
> +  signed short dw2_regnum[2];
>  #define Dw2Inval (-1)
>  }
>  reg_entry;

It's a little sad that non-64-bit field also has its size increased.
Right now either way the structure size as a whole is the same, but
down the road this may end up a little wasteful.

Jan