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Re: [ft-devel] FT_MulFix assembly
From: |
Miles Bader |
Subject: |
Re: [ft-devel] FT_MulFix assembly |
Date: |
Tue, 7 Sep 2010 09:44:57 +0900 |
On Tue, Sep 7, 2010 at 4:28 AM, James Cloos <address@hidden> wrote:
>>>>>> "MB" == Miles Bader <address@hidden> writes:
>
> MB> The compiler generates the following assembly:
>
> MB> mov %esi, %eax
> MB> mov %edi, %edi
> MB> imulq %rdi, %rax
> MB> addq $32768, %rax
> MB> shrq $16, %rax
>
> That does not match the C code though; it rounds negative values wrong.
>
> The C version does away-from-zero rounding.
Do you have test cases that show this? I tried using random inputs,
but even up to billions of iterations, I can't seem to find a set of
inputs where my function yields different results from yours.
Thanks,
-Miles
--
Cat is power. Cat is peace.
- Re: [ft-devel] FT_MulFix assembly, James Cloos, 2010/09/05
- Re: [ft-devel] FT_MulFix assembly, Graham Asher, 2010/09/06
- Re: [ft-devel] FT_MulFix assembly, Miles Bader, 2010/09/06
- Re: [ft-devel] FT_MulFix assembly, Miles Bader, 2010/09/06
- Re: [ft-devel] FT_MulFix assembly, Miles Bader, 2010/09/06
- Re: [ft-devel] FT_MulFix assembly, James Cloos, 2010/09/06
- Re: [ft-devel] FT_MulFix assembly,
Miles Bader <=
- Re: [ft-devel] FT_MulFix assembly, James Cloos, 2010/09/07
- Re: [ft-devel] FT_MulFix assembly, Miles Bader, 2010/09/07
- Re: [ft-devel] FT_MulFix assembly, James Cloos, 2010/09/07
- Re: [ft-devel] FT_MulFix assembly, Miles Bader, 2010/09/07
- Re: [ft-devel] FT_MulFix assembly, James Cloos, 2010/09/18
- Re: [ft-devel] FT_MulFix assembly, Werner LEMBERG, 2010/09/19