Re: [Qemu-devel] [PATCH v3] linux-user: Handle compressed ISA encodings when processing MIPS exceptions

[Maciej W. Rozycki]

On Fri, 19 Jul 2013, Kwok Cheung Yeung wrote:

> Decode trap instructions during the handling of an EXCP_BREAK or EXCP_TRAP
> according to the current ISA mode.
> 
> Signed-off-by: Kwok Cheung Yeung <address@hidden>
> ---
>  linux-user/main.c | 46 +++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 43 insertions(+), 3 deletions(-)
> 
> v2->v3: Handle microMIPS and MIPS16e instructions when processing EXCP_BREAK.
> 
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 7f15d3d..b137216 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -2348,7 +2348,31 @@ done_syscall:
>                  abi_ulong trap_instr;
>                  unsigned int code;
>  
> -                ret = get_user_ual(trap_instr, env->active_tc.PC);
> +                if (env->hflags & MIPS_HFLAG_M16) {
> +                    if (env->insn_flags & ASE_MICROMIPS) {
> +                        /* microMIPS mode */
> +                        abi_ulong instr[2];
> +
> +                        ret = get_user_u16(instr[0], env->active_tc.PC) ||
> +                              get_user_u16(instr[1], env->active_tc.PC + 2);
> +
> +                        trap_instr = (instr[0] << 16) | instr[1];

 You need to tell 16-bit and 32-bit microMIPS BREAK instructions apart 
somehow.

  Maciej