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Re: [Qemu-devel] [PATCH v2 13/20] fpu/softfloat: re-factor div
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v2 13/20] fpu/softfloat: re-factor div |
Date: |
Fri, 12 Jan 2018 16:22:19 +0000 |
On 9 January 2018 at 12:22, Alex Bennée <address@hidden> wrote:
> We can now add float16_div 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>
> ---
> fpu/softfloat-macros.h | 44 +++++++++
> fpu/softfloat.c | 235
> ++++++++++++++++++------------------------------
> include/fpu/softfloat.h | 1 +
> 3 files changed, 134 insertions(+), 146 deletions(-)
>
> diff --git a/fpu/softfloat-macros.h b/fpu/softfloat-macros.h
> index 9cc6158cb4..980be2c051 100644
> --- a/fpu/softfloat-macros.h
> +++ b/fpu/softfloat-macros.h
> @@ -625,6 +625,50 @@ static uint64_t estimateDiv128To64( uint64_t a0,
> uint64_t a1, uint64_t b )
>
> }
>
> +/* Nicked from gmp longlong.h __udiv_qrnnd */
Can we have a copyright/license attribution for code we nick
from other projects, please? :-)
> +static uint64_t div128To64(uint64_t n0, uint64_t n1, uint64_t d)
> +{
> + uint64_t d0, d1, q0, q1, r1, r0, m;
> +
> + d0 = (uint32_t)d;
> + d1 = d >> 32;
> +
> + r1 = n1 % d1;
> + q1 = n1 / d1;
> + m = q1 * d0;
> + r1 = (r1 << 32) | (n0 >> 32);
> + if (r1 < m) {
> + q1 -= 1;
> + r1 += d;
> + if (r1 >= d) {
> + if (r1 < m) {
> + q1 -= 1;
> + r1 += d;
> + }
> + }
> + }
> + r1 -= m;
> +
> + r0 = r1 % d1;
> + q0 = r1 / d1;
> + m = q0 * d0;
> + r0 = (r0 << 32) | (uint32_t)n0;
> + if (r0 < m) {
> + q0 -= 1;
> + r0 += d;
> + if (r0 >= d) {
> + if (r0 < m) {
> + q0 -= 1;
> + r0 += d;
> + }
> + }
> + }
> + r0 -= m;
> +
> + /* Return remainder in LSB */
> + return (q1 << 32) | q0 | (r0 != 0);
> +}
thanks
-- PMM
- Re: [Qemu-devel] [PATCH v2 11/20] fpu/softfloat: re-factor add/sub, (continued)
- [Qemu-devel] [PATCH v2 14/20] fpu/softfloat: re-factor muladd, Alex Bennée, 2018/01/09
- [Qemu-devel] [PATCH v2 16/20] fpu/softfloat: re-factor float to int/uint, Alex Bennée, 2018/01/09
- [Qemu-devel] [PATCH v2 19/20] fpu/softfloat: re-factor minmax, Alex Bennée, 2018/01/09
- [Qemu-devel] [PATCH v2 18/20] fpu/softfloat: re-factor scalbn, Alex Bennée, 2018/01/09
- [Qemu-devel] [PATCH v2 13/20] fpu/softfloat: re-factor div, Alex Bennée, 2018/01/09
- Re: [Qemu-devel] [PATCH v2 13/20] fpu/softfloat: re-factor div,
Peter Maydell <=
- [Qemu-devel] [PATCH v2 20/20] fpu/softfloat: re-factor compare, Alex Bennée, 2018/01/09
- [Qemu-devel] [PATCH v2 17/20] fpu/softfloat: re-factor int/uint to float, Alex Bennée, 2018/01/09
- [Qemu-devel] [PATCH v2 15/20] fpu/softfloat: re-factor round_to_int, Alex Bennée, 2018/01/09
- Re: [Qemu-devel] [PATCH v2 00/20] re-factor softfloat and add fp16 functions, no-reply, 2018/01/09