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Re: [Qemu-ppc] [Qemu-devel] [V4 PATCH 03/22] softfloat: Fix float64_to_u
From: |
Peter Maydell |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [V4 PATCH 03/22] softfloat: Fix float64_to_uint64_round_to_zero |
Date: |
Thu, 19 Dec 2013 21:43:42 +0000 |
On 18 December 2013 20:19, Tom Musta <address@hidden> wrote:
> The float64_to_uint64_round_to_zero routine is incorrect.
>
> For example, the following test pattern:
>
> 46697351FF4AEC29 / 0x1.97351ff4aec29p+103
>
> currently produces 8000000000000000 instead of FFFFFFFFFFFFFFFF.
>
> This patch re-implements the routine to temporarily force the
> rounding mode and use the float64_to_uint64 routine.
>
> This contribution can be licensed under either the softfloat-2a or -2b
> license.
>
> Signed-off-by: Tom Musta <address@hidden>
Reviewed-by: Peter Maydell <address@hidden>
The other approach would be to make all the conversion
functions explicitly take the rounding mode parameter
(and in some ways that might be closer to the set of
functionality IEE754-2008 describes), but this is a
simple change and saving and restoring rounding mode
is very cheap.
thanks
-- PMM
- [Qemu-ppc] [V4 PATCH 00/22] PowerPC VSX Stage 3, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 01/22] softfloat: Fix float64_to_uint64, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 02/22] softfloat: Add float32_to_uint64(), Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 03/22] softfloat: Fix float64_to_uint64_round_to_zero, Tom Musta, 2013/12/18
- Re: [Qemu-ppc] [Qemu-devel] [V4 PATCH 03/22] softfloat: Fix float64_to_uint64_round_to_zero,
Peter Maydell <=
- [Qemu-ppc] [V4 PATCH 04/22] softfloat: Fix float64_to_uint32, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 05/22] softfloat: Fix float64_to_uint32_round_to_zero, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 06/22] target-ppc: Add set_fprf Argument to fload_invalid_op_excp(), Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 07/22] target-ppc: General Support for VSX Helpers, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 08/22] target-ppc: Add VSX ISA2.06 xadd/xsub Instructions, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 10/22] target-ppc: Add VSX ISA2.06 xdiv Instructions, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 09/22] target-ppc: Add VSX ISA2.06 xmul Instructions, Tom Musta, 2013/12/18
- [Qemu-ppc] [V4 PATCH 12/22] target-ppc: Add VSX ISA2.06 xsqrt Instructions, Tom Musta, 2013/12/18