Segher Boessenkool wrote:
On Wed, Aug 31, 2022 at 12:50:07PM +0000, Christophe Leroy wrote:
Le 29/08/2022 à 07:52, Sathvika Vasireddy a écrit :
> +  opcode = insn >> 26;
> +
> +  switch (opcode) {
> +  case 18: /* bl */

case 18 is more than 'bl', it includes also 'b'.
In both cases, the calculation of *immediate is the same.

It also is "ba" and "bla", sometimes written as "b[l][a]".

It would therefore be more correct to perform the calculation and setup of *immediate outside the 'if ((insn & 3) == 1)', that would avoid unnecessary churn the day we add support for branches without link.

Yeah, and probably move the comments around:

+       case 18: /* b[l][a] */
+               if ((insn & 3) == 1) { /* bl */


> +          if ((insn & 3) == 1) {
> +                  *type = INSN_CALL;
> +                  *immediate = insn & 0x3fffffc;
> +                  if (*immediate & 0x2000000)
> +                          *immediate -= 0x4000000;
> +          }
> +          break;
> +  }

Does this handle AA=1 correctly at all?  That is valid both with and
without relocations, just like AA=0.  Same for AA=1 LK=0 btw.

If you only handle AA=0, the code should explicitly test for that.

The code does test for AA=0 LK=1 with the if statement there?


- Naveen

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