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Re: [Qemu-devel] [PATCH v2 05/67] target/arm: Implement SVE load vector/
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v2 05/67] target/arm: Implement SVE load vector/predicate |
Date: |
Thu, 22 Feb 2018 11:31:57 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 |
On 02/22/2018 10:20 AM, Peter Maydell wrote:
> On 17 February 2018 at 18:22, Richard Henderson
> <address@hidden> wrote:
>> Signed-off-by: Richard Henderson <address@hidden>
>> ---
>> target/arm/translate-sve.c | 132
>> +++++++++++++++++++++++++++++++++++++++++++++
>> target/arm/sve.decode | 22 +++++++-
>> 2 files changed, 153 insertions(+), 1 deletion(-)
>>
>> diff --git a/target/arm/translate-sve.c b/target/arm/translate-sve.c
>> index 50cf2a1fdd..c0cccfda6f 100644
>> --- a/target/arm/translate-sve.c
>> +++ b/target/arm/translate-sve.c
>> @@ -46,6 +46,19 @@ typedef void GVecGen3Fn(unsigned, uint32_t, uint32_t,
>> * Implement all of the translator functions referenced by the decoder.
>> */
>>
>> +/* Return the offset info CPUARMState of the predicate vector register Pn.
>> + * Note for this purpose, FFR is P16. */
>
> Missing newline before */.
>
>> +/*
>> + *** SVE Memory - 32-bit Gather and Unsized Contiguous Group
>> + */
>> +
>> +/* Subroutine loading a vector register at VOFS of LEN bytes.
>> + * The load should begin at the address Rn + IMM.
>> + */
>> +
>> +#if UINTPTR_MAX == UINT32_MAX
>> +# define ptr i32
>> +#else
>> +# define ptr i64
>> +#endif
>
> I think that rather than doing this we should improve the
> provision that tcg/tcg-op.h has for *_ptr() wrappers, so
> from the target's point of view it has a proper tcg_const_local_ptr()
> and tcg_gen_brcondi_ptr(), same as for _i32, _i64 and _tl.
>
>> +
>> +static void do_ldr(DisasContext *s, uint32_t vofs, uint32_t len,
>> + int rn, int imm)
>> +{
>> + uint32_t len_align = QEMU_ALIGN_DOWN(len, 8);
>> + uint32_t len_remain = len % 8;
>> + uint32_t nparts = len / 8 + ctpop8(len_remain);
>> + int midx = get_mem_index(s);
>> + TCGv_i64 addr, t0, t1;
>> +
>> + addr = tcg_temp_new_i64();
>> + t0 = tcg_temp_new_i64();
>> +
>> + /* Note that unpredicated load/store of vector/predicate registers
>> + * are defined as a stream of bytes, which equates to little-endian
>> + * operations on larger quantities. There is no nice way to force
>> + * a little-endian load for aarch64_be-linux-user out of line.
>> + *
>> + * Attempt to keep code expansion to a minimum by limiting the
>> + * amount of unrolling done.
>> + */
>> + if (nparts <= 4) {
>> + int i;
>> +
>> + for (i = 0; i < len_align; i += 8) {
>> + tcg_gen_addi_i64(addr, cpu_reg_sp(s, rn), imm + i);
>> + tcg_gen_qemu_ld_i64(t0, addr, midx, MO_LEQ);
>> + tcg_gen_st_i64(t0, cpu_env, vofs + i);
>> + }
>> + } else {
>> + TCGLabel *loop = gen_new_label();
>> + TCGv_ptr i = TCGV_NAT_TO_PTR(glue(tcg_const_local_, ptr)(0));
>> + TCGv_ptr dest;
>> +
>> + gen_set_label(loop);
>> +
>> + /* Minimize the number of local temps that must be re-read from
>> + * the stack each iteration. Instead, re-compute values other
>> + * than the loop counter.
>> + */
>> + dest = tcg_temp_new_ptr();
>> + tcg_gen_addi_ptr(dest, i, imm);
>> +#if UINTPTR_MAX == UINT32_MAX
>> + tcg_gen_extu_i32_i64(addr, TCGV_PTR_TO_NAT(dest));
>> + tcg_gen_add_i64(addr, addr, cpu_reg_sp(s, rn));
>> +#else
>> + tcg_gen_add_i64(addr, TCGV_PTR_TO_NAT(dest), cpu_reg_sp(s, rn));
>> +#endif
>
> Can we avoid the ifdef by creating a tcg_gen_ext_ptr_i64() (similar
> to but opposite in effect to the existing tcg_gen_ext_i32_ptr()) ?
Ok, I will improve tcg.h as necessary for better support of TCGv_ptr.
>> address@hidden ........ ... rm:5 ... ... rn:5 rd:5 &rrr_esz
>> esz=0
>> address@hidden ........ ... rm:5 ... ... rn:5 rd:5 &rrr_esz
>> esz=0
>
> This change looks like it should be squashed into a previous patch?
Ho hum, I thought I got all of these. I'll take another look through.
r~
- Re: [Qemu-devel] [Qemu-arm] [PATCH v2 02/67] target/arm: Introduce translate-a64.h, (continued)
- [Qemu-devel] [PATCH v2 03/67] target/arm: Add SVE decode skeleton, Richard Henderson, 2018/02/17
- [Qemu-devel] [PATCH v2 04/67] target/arm: Implement SVE Bitwise Logical - Unpredicated Group, Richard Henderson, 2018/02/17
- [Qemu-devel] [PATCH v2 05/67] target/arm: Implement SVE load vector/predicate, Richard Henderson, 2018/02/17
- [Qemu-devel] [PATCH v2 06/67] target/arm: Implement SVE predicate test, Richard Henderson, 2018/02/17
- [Qemu-devel] [PATCH v2 07/67] target/arm: Implement SVE Predicate Logical Operations Group, Richard Henderson, 2018/02/17
- [Qemu-devel] [PATCH v2 08/67] target/arm: Implement SVE Predicate Misc Group, Richard Henderson, 2018/02/17
- [Qemu-devel] [PATCH v2 09/67] target/arm: Implement SVE Integer Binary Arithmetic - Predicated Group, Richard Henderson, 2018/02/17