Re: [Qemu-devel] [PATCH][SPARC] Fix handling of conditional branches in delay slot of a conditional branch

[Artyom Tarasenko]

Since it's a pure bug fix, do you think can it be applied to 0.15 as well?

On Sat, Aug 6, 2011 at 10:14 PM, Blue Swirl <address@hidden> wrote:
> Thanks, applied.
>
> On Sat, Aug 6, 2011 at 3:01 PM, Artyom Tarasenko <address@hidden> wrote:
>> Check whether dc->npc is dynamic before using its value for branch.
>>
>> Signed-off-by: Artyom Tarasenko <address@hidden>
>> ---
>> Particaluary the patch fixes handling of the constructions like
>>
>> 0x13e26c0:  brz,pn   %o0, 0x13e26e4
>> 0x13e26c4:  brlez,pn   %o1, 0x13e26e4
>>
>> present in NetBSD-5.1
>>
>>  target-sparc/translate.c |   30 +++++++++++++++++++++---------
>>  1 files changed, 21 insertions(+), 9 deletions(-)
>>
>> diff --git a/target-sparc/translate.c b/target-sparc/translate.c
>> index 958fbc5..dee67b3 100644
>> --- a/target-sparc/translate.c
>> +++ b/target-sparc/translate.c
>> @@ -1286,7 +1286,6 @@ static inline void gen_cond_reg(TCGv r_dst, int cond, 
>> TCGv r_src)
>>  }
>>  #endif
>>
>> -/* XXX: potentially incorrect if dynamic npc */
>>  static void do_branch(DisasContext *dc, int32_t offset, uint32_t insn, int 
>> cc,
>>                       TCGv r_cond)
>>  {
>> @@ -1321,13 +1320,17 @@ static void do_branch(DisasContext *dc, int32_t 
>> offset, uint32_t insn, int cc,
>>         } else {
>>             dc->pc = dc->npc;
>>             dc->jump_pc[0] = target;
>> -            dc->jump_pc[1] = dc->npc + 4;
>> -            dc->npc = JUMP_PC;
>> +            if (unlikely(dc->npc == DYNAMIC_PC)) {
>> +                dc->jump_pc[1] = DYNAMIC_PC;
>> +                tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
>> +            } else {
>> +                dc->jump_pc[1] = dc->npc + 4;
>> +                dc->npc = JUMP_PC;
>> +            }
>>         }
>>     }
>>  }
>>
>> -/* XXX: potentially incorrect if dynamic npc */
>>  static void do_fbranch(DisasContext *dc, int32_t offset, uint32_t insn, int 
>> cc,
>>                       TCGv r_cond)
>>  {
>> @@ -1362,14 +1365,18 @@ static void do_fbranch(DisasContext *dc, int32_t 
>> offset, uint32_t insn, int cc,
>>         } else {
>>             dc->pc = dc->npc;
>>             dc->jump_pc[0] = target;
>> -            dc->jump_pc[1] = dc->npc + 4;
>> -            dc->npc = JUMP_PC;
>> +            if (unlikely(dc->npc == DYNAMIC_PC)) {
>> +                dc->jump_pc[1] = DYNAMIC_PC;
>> +                tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
>> +            } else {
>> +                dc->jump_pc[1] = dc->npc + 4;
>> +                dc->npc = JUMP_PC;
>> +            }
>>         }
>>     }
>>  }
>>
>>  #ifdef TARGET_SPARC64
>> -/* XXX: potentially incorrect if dynamic npc */
>>  static void do_branch_reg(DisasContext *dc, int32_t offset, uint32_t insn,
>>                           TCGv r_cond, TCGv r_reg)
>>  {
>> @@ -1384,8 +1391,13 @@ static void do_branch_reg(DisasContext *dc, int32_t 
>> offset, uint32_t insn,
>>     } else {
>>         dc->pc = dc->npc;
>>         dc->jump_pc[0] = target;
>> -        dc->jump_pc[1] = dc->npc + 4;
>> -        dc->npc = JUMP_PC;
>> +        if (unlikely(dc->npc == DYNAMIC_PC)) {
>> +            dc->jump_pc[1] = DYNAMIC_PC;
>> +            tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
>> +        } else {
>> +            dc->jump_pc[1] = dc->npc + 4;
>> +            dc->npc = JUMP_PC;
>> +        }
>>     }
>>  }
>>
>> --
>> 1.7.3.4
>>
>>
>



-- 
Regards,
Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/