Re: [Qemu-devel] [PATCH] target-ppc: add extended opcodes for dcbt

[Alexander Graf]

On 20.02.2014, at 14:01, Cédric Le Goater <address@hidden> wrote:

> The latest glibc provides a memrchr routine using an extended opcode 
> of the 'dcbt' instruction :
> 
> 00000000000a7cc0 <memrchr>:
>   a7cc0:       11 00 4c 3c     addis   r2,r12,17
>   a7cc4:       b8 f8 42 38     addi    r2,r2,-1864
>   a7cc8:       14 2a e3 7c     add     r7,r3,r5
>   a7ccc:       d0 00 07 7c     neg     r0,r7
>   a7cd0:       ff ff e7 38     addi    r7,r7,-1
>   a7cd4:       78 1b 6a 7c     mr      r10,r3
>   a7cd8:       24 06 e6 78     rldicr  r6,r7,0,56
>   a7cdc:       60 00 20 39     li      r9,96
>   a7ce0:       2c 32 09 7e     dcbtt   r9,r6
>   ....
> 
> which breaks grep, and other commands, in TCG mode :
> 
>   invalid bits: 02000000 for opcode: 1f - 16 - 08 (7e09322c) 00003fff799feca0
> 
> This patch adds the extended opcodes as no-ops just like the 'dcbt'
> instruction. Other 'dcb*' instructions might be impacted but they 
> have not showed up yet.
> 
> Signed-off-by: Cédric Le Goater <address@hidden>

Please also remove the 0x02 bit from dcbtst. I don't see anything in 2.07 
indicating that that bit should be reserved and I prefer to have those two 
instructions be consistent with each other.


Alex

> ---
> target-ppc/translate.c |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index 951f15e055d4..431358a83ac3 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -9596,7 +9596,7 @@ GEN_HANDLER(mtspr, 0x1F, 0x13, 0x0E, 0x00000001, 
> PPC_MISC),
> GEN_HANDLER(dcbf, 0x1F, 0x16, 0x02, 0x03C00001, PPC_CACHE),
> GEN_HANDLER(dcbi, 0x1F, 0x16, 0x0E, 0x03E00001, PPC_CACHE),
> GEN_HANDLER(dcbst, 0x1F, 0x16, 0x01, 0x03E00001, PPC_CACHE),
> -GEN_HANDLER(dcbt, 0x1F, 0x16, 0x08, 0x02000001, PPC_CACHE),
> +GEN_HANDLER(dcbt, 0x1F, 0x16, 0x08, 0x00000001, PPC_CACHE),
> GEN_HANDLER(dcbtst, 0x1F, 0x16, 0x07, 0x02000001, PPC_CACHE),
> GEN_HANDLER(dcbz, 0x1F, 0x16, 0x1F, 0x03C00001, PPC_CACHE_DCBZ),
> GEN_HANDLER(dst, 0x1F, 0x16, 0x0A, 0x01800001, PPC_ALTIVEC),
> -- 
> 1.7.10.4
>