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Re: [Qemu-devel] [PATCH 46/60] AArch64: Add rev instruction family emula
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH 46/60] AArch64: Add rev instruction family emulation |
Date: |
Fri, 27 Sep 2013 14:07:41 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130805 Thunderbird/17.0.8 |
On 09/26/2013 05:48 PM, Alexander Graf wrote:
> This patch adds emlulation support for rev and rbit instructions.
>
> Signed-off-by: Alexander Graf <address@hidden>
> ---
> target-arm/helper-a64.c | 19 +++++++++++++++++++
> target-arm/helper-a64.h | 1 +
> target-arm/translate-a64.c | 38 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 58 insertions(+)
>
> diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
> index a56ce75..e20b89f 100644
> --- a/target-arm/helper-a64.c
> +++ b/target-arm/helper-a64.c
> @@ -237,3 +237,22 @@ int64_t HELPER(sdiv64)(int64_t num, int64_t den)
> return LLONG_MIN;
> return num / den;
> }
> +
> +uint64_t HELPER(rbit64)(uint64_t x)
> +{
> + x = ((x & 0xff00000000000000ULL) >> 56)
> + | ((x & 0x00ff000000000000ULL) >> 40)
> + | ((x & 0x0000ff0000000000ULL) >> 24)
> + | ((x & 0x000000ff00000000ULL) >> 8)
> + | ((x & 0x00000000ff000000ULL) << 8)
> + | ((x & 0x0000000000ff0000ULL) << 24)
> + | ((x & 0x000000000000ff00ULL) << 40)
> + | ((x & 0x00000000000000ffULL) << 56);
This first step is of course bswap64, no?
> + case 0x0: /* RBIT */
> + if (is_32bit) {
> + tcg_tmp = tcg_temp_new_i32();
> + tcg_gen_trunc_i64_i32(tcg_tmp, cpu_reg(rn));
> + gen_helper_rbit(tcg_tmp, tcg_tmp);
> + tcg_gen_extu_i32_i64(cpu_reg(rd), tcg_tmp);
> + tcg_temp_free_i32(tcg_tmp);
> + } else {
> + gen_helper_rbit64(cpu_reg(rd), cpu_reg(rn));
> + }
I suppose that works. Alternately, compute as
rd = rbit64(rn << 32);
> + case 0x1: /* REV16 */
> + tcg_gen_bswap16_i64(cpu_reg(rd), cpu_reg(rn));
> + break;
> + case 0x2: /* REV32 */
> + tcg_gen_bswap32_i64(cpu_reg(rd), cpu_reg(rn));
> + break;
Aren't these two wrong? Doesn't revN swap pairs of N bits
all the way up the register? See gen_rev16 for A32.
Certainly one could use bswap32_i64 for REV32 if is_32bit.
r~
- [Qemu-devel] [PATCH 37/60] AArch64: Add hint instruction emulation, (continued)
- [Qemu-devel] [PATCH 37/60] AArch64: Add hint instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 39/60] AArch64: Add stub sys instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 34/60] AArch64: Add b.cond instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 43/60] AArch64: Add cinc instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 45/60] AArch64: Add shift instruction family emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 47/60] AArch64: Add clz instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 40/60] AArch64: Add tbz instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 46/60] AArch64: Add rev instruction family emulation, Alexander Graf, 2013/09/26
- Re: [Qemu-devel] [PATCH 46/60] AArch64: Add rev instruction family emulation,
Richard Henderson <=
- [Qemu-devel] [PATCH 48/60] AArch64: Add 0x1a encoding of add instructions, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 44/60] AArch64: Add division instruction family emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 41/60] AArch64: Add ldr/str instruction family emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 49/60] AArch64: Add "Data-processing (3 source)" instruction, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 51/60] AArch64: Add fmov (scalar, immediate) instruction, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 56/60] AArch64: Add "Floating-point data-processing (2, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 58/60] AArch64: Add "ADD (vector)" instruction emulation, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 57/60] AArch64: Add "Floating-point data-processing (2, Alexander Graf, 2013/09/26
- [Qemu-devel] [PATCH 42/60] AArch64: Add literal ld instruction emulation, Alexander Graf, 2013/09/26