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Re: [Qemu-devel] [PATCH v4 13/22] fpu/softfloat: re-factor mul
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v4 13/22] fpu/softfloat: re-factor mul |
Date: |
Tue, 13 Feb 2018 15:20:51 +0000 |
On 6 February 2018 at 16:48, Alex Bennée <address@hidden> wrote:
> We can now add float16_mul and use the common decompose and
> canonicalize functions to have a single implementation for
> float16/32/64 versions.
>
> Signed-off-by: Alex Bennée <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
>
> ---
> v3
> +/*
> + * Returns the result of multiplying the floating-point values `a' and
> + * `b'. The operation is performed according to the IEC/IEEE Standard
> + * for Binary Floating-Point Arithmetic.
> + */
> +
> +static FloatParts mul_floats(FloatParts a, FloatParts b, float_status *s)
> +{
> + bool sign = a.sign ^ b.sign;
> +
> + if (a.cls == float_class_normal && b.cls == float_class_normal) {
> + uint64_t hi, lo;
> + int exp = a.exp + b.exp;
> +
> + mul64To128(a.frac, b.frac, &hi, &lo);
It seems a shame that we previously were able to use a
32x32->64 multiply for the float32 case, and now we have to
do an expensive 64x64->128 multiply regardless...
Regardless
Reviewed-by: Peter Maydell <address@hidden>
thanks
-- PMM
- Re: [Qemu-devel] [PATCH v4 22/22] fpu/softfloat: re-factor sqrt, (continued)
Re: [Qemu-devel] [PATCH v4 22/22] fpu/softfloat: re-factor sqrt, Richard Henderson, 2018/02/13
[Qemu-devel] [PATCH v4 20/22] fpu/softfloat: re-factor minmax, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 19/22] fpu/softfloat: re-factor scalbn, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 21/22] fpu/softfloat: re-factor compare, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 11/22] fpu/softfloat: define decompose structures, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 18/22] fpu/softfloat: re-factor int/uint to float, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 13/22] fpu/softfloat: re-factor mul, Alex Bennée, 2018/02/06
- Re: [Qemu-devel] [PATCH v4 13/22] fpu/softfloat: re-factor mul,
Peter Maydell <=
[Qemu-devel] [PATCH v4 15/22] fpu/softfloat: re-factor muladd, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 17/22] fpu/softfloat: re-factor float to int/uint, Alex Bennée, 2018/02/06
[Qemu-devel] [PATCH v4 12/22] fpu/softfloat: re-factor add/sub, Alex Bennée, 2018/02/06
Re: [Qemu-devel] [PATCH v4 00/22] re-factor softfloat and add fp16 functions, no-reply, 2018/02/07
Re: [Qemu-devel] [PATCH v4 00/22] re-factor softfloat and add fp16 functions, Peter Maydell, 2018/02/13