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Re: [Qemu-devel] [PATCH 5/6] target-arm: A64: Implement PMULL instructio
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH 5/6] target-arm: A64: Implement PMULL instruction |
Date: |
Mon, 17 Feb 2014 22:59:06 +0000 |
On 17 February 2014 16:29, Richard Henderson <address@hidden> wrote:
> On 02/16/2014 12:21 PM, Peter Maydell wrote:
>> +/* Helper function for 64 bit polynomial multiply case:
>> + * perform PolynomialMult(op1, op2) and return either the top or
>> + * bottom half of the 128 bit result.
>> + */
>> +uint64_t HELPER(neon_pmull_64_lo)(CPUARMState *env, uint64_t op1, uint64_t
>> op2)
>> +{
>> + int bitnum;
>> + uint64_t res = 0;
>> +
>> + for (bitnum = 0; bitnum < 64; bitnum++) {
>> + if (op1 & (1ULL << bitnum)) {
>> + res ^= op2 << bitnum;
>> + }
>> + }
>> + return res;
>> +}
>
> These functions don't use env. Why are you passing it?
Oops, that's leftover from my initial approach to the problem, which
used a single helper to calculate the full 128 bit result (and which
thus needed env so it could write to env->vfp.regs, since C and TCG
don't support multiple return values or 128 bit returns). I'll remove it.
thanks
-- PMM
- [Qemu-devel] [PATCH 0/6] A64: finish Neon 3-reg-diff category, add LDTR/STTR, Peter Maydell, 2014/02/16
- [Qemu-devel] [PATCH 1/6] target-arm: A64: Add opcode comments to disas_simd_three_reg_diff, Peter Maydell, 2014/02/16
- [Qemu-devel] [PATCH 5/6] target-arm: A64: Implement PMULL instruction, Peter Maydell, 2014/02/16
- [Qemu-devel] [PATCH 4/6] target-arm: A64: Implement narrowing three-reg-diff operations, Peter Maydell, 2014/02/16
- [Qemu-devel] [PATCH 3/6] target-arm: A64: Implement the wide 3-reg-different operations, Peter Maydell, 2014/02/16
- [Qemu-devel] [PATCH 6/6] target-arm: A64: Implement unprivileged load/store, Peter Maydell, 2014/02/16
- [Qemu-devel] [PATCH 2/6] target-arm: A64: Add most remaining three-reg-diff widening ops, Peter Maydell, 2014/02/16
- Re: [Qemu-devel] [PATCH 0/6] A64: finish Neon 3-reg-diff category, add LDTR/STTR, Richard Henderson, 2014/02/17