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Re: [Qemu-devel] [PATCH 04/13] target-ppc: implement lxvll instruction
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH 04/13] target-ppc: implement lxvll instruction |
Date: |
Mon, 5 Dec 2016 09:52:35 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
On 12/05/2016 03:25 AM, Nikunj A Dadhania wrote:
> +void helper_lxvll(CPUPPCState *env, target_ulong addr,
> + target_ulong xt_num, target_ulong rb)
> +{
> + ppc_vsr_t xt;
> +
> + getVSR(xt_num, &xt, env);
> + if (unlikely((rb & 0xFF) == 0)) {
> + xt.s128 = int128_make128(0, 0);
Nit: int128_zero.
> + } else {
> + target_ulong end = ((rb & 0xFF) * 8) - 1;
> + if (msr_le) {
> + xt.u64[LO_IDX] = cpu_ldq_data_ra(env, addr, GETPC());
> + addr = addr_add(env, addr, 8);
> + xt.u64[HI_IDX] = cpu_ldq_data_ra(env, addr, GETPC());
> + xt.s128 = int128_and(xt.s128, mask_u128(127 - end, 127));
The ISA document says that this is a sequence of byte operations. Which means
that END < 127 will not access bytes outside of the length. Which means that
your code will trigger SIGSEGV near page boundaries when real hardware won't.
I also don't see how this does the right thing for little-endian.
r~
- Re: [Qemu-devel] [PATCH 02/13] target-ppc: add mask_u128 routine, (continued)
- [Qemu-devel] [PATCH 03/13] target-ppc: implement lxvl instruction, Nikunj A Dadhania, 2016/12/05
- [Qemu-devel] [PATCH 01/13] target-ppc: move ppc_vsr_t to common header, Nikunj A Dadhania, 2016/12/05
- [Qemu-devel] [PATCH 05/13] target-ppc: implement stxvl instruction, Nikunj A Dadhania, 2016/12/05
- [Qemu-devel] [PATCH 04/13] target-ppc: implement lxvll instruction, Nikunj A Dadhania, 2016/12/05
- Re: [Qemu-devel] [PATCH 04/13] target-ppc: implement lxvll instruction,
Richard Henderson <=
- [Qemu-devel] [PATCH 06/13] target-ppc: implement stxvll instructions, Nikunj A Dadhania, 2016/12/05
- [Qemu-devel] [PATCH 07/13] target-ppc: implement xxextractuw instruction, Nikunj A Dadhania, 2016/12/05
- [Qemu-devel] [PATCH 09/13] target-ppc: implement stop instruction, Nikunj A Dadhania, 2016/12/05
- [Qemu-devel] [PATCH 08/13] target-ppc: implement xxinsertw instruction, Nikunj A Dadhania, 2016/12/05