Re: [Qemu-devel] cvttps2dq, movdq2q, movq2dq incorrect behaviour

[Julian Seward <jseward@acm.org>]

Malc, your sse-movq.patch works for me.  Thanks.

> soft-float was a red herring, translate.c is at fault here (interpreter
> does not use it, hence behaved correctly)
>
> translate.c:3009
> if (b1 >= 2 && ((b >= 0x50 && b <= 0x5f) ||
>                  b == 0xc2)) {
>      /* specific case for SSE single instructions */
>      if (b1 == 2) {
>          /* 32 bit access */
>          gen_op_ld_T0_A0[OT_LONG + s->mem_index]();
>          gen_op_movl_env_T0(offsetof(CPUX86State,xmm_t0.XMM_L(0)));
>      } else {
>          /* 64 bit access */
>          gen_ldq_env_A0[s->mem_index >>
> 2](offsetof(CPUX86State,xmm_t0.XMM_D(0))); }
> } else {
>      gen_ldo_env_A0[s->mem_index >> 2](op2_offset);
> }
>
> cvttps2dq is 0x5b(b=0x5b) with repn prefix (b1=2) the above code is
> optimized a bit more than it should have been, as it loads only 4 bytes
> into xmm_t0 instead of 16.

Uh, fine, but I don't understand how/what to fix.  Can you advise?

J