On Mon, 12 Dec 2005 14:25:16 -0800 (PST)
Glen Kriekenbeck <Glen.Kriekenbeck at Sun.COM> wrote:
> Hi Peter and everyone,
>
> Thanks for the details on these relocations. My correspondent has several
> related questions.
>
> [i]> 1. Nothing has been said about the relocation type R_SPARC_H34.[/i]
> This question got buried under the ...GOTDATA... question; earlier, he asked
> about "...codes 80 to 85 (we can probably figure out the first four but not
> the last two)." Do you have any info on code 85?
R_SPARC_H34 (together with R_SPARC_L34) is used for 34-bit absolute
addressing model for 64-bit apps. Formulas in the manual are correct:
Name Value Field Calculation
---------------------------------------------
R_SPARC_H34 85 V-imm22 (S+A) >> 12
R_SPARC_L34 52 T-imm13 (S+A) & 0xfff
R_SPARC_L34 is an alias for R_SPARC_L44 and thus does not require
new definition.
Example of abs34 code:
sethi %h34(addr), %r1 ! Load bits 12-33
sllx %r1, 2, %r2
ld [%r2 + %l34(addr)], %r3 ! Add bits 0-11
Currently this code model is only generated by compiler internal option.
Regards,
Maksim
>
> [i]> 2. In the corrected expressions for the relocated values right shift by
> 31 bits
> should be construed as arithmetical, not logical shift, but this is not
> stated clearly.[/i]
> Is this a correct assumption? If so, it probably should be stated directly.
>
> Finally, two followup questions from Peter's earlier note:
> [i]> 3. In Peter's example of modification of code by linker, the modified
> version should
> probably have relocations without "OP" (I wonder though, in what case
> linker needs to output unresolved relocations).[/i]
>
> [i]> 4. In Peter's explanations for the case of negative offset it is assumed
> that the low
> 12 bits will be zeros after sethi, which should mean that the low 2 bits of
> the relocated operand of sethi should be zeroed by the relocation; if this is
> not done, what would happen to the bits 12 and 11 in the resulting value?[/i]
>
> Thanks!
> glen
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