NetBSD Problem Report #47810
From www@NetBSD.org Thu May 9 05:29:44 2013
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Date: Thu, 9 May 2013 05:29:42 +0000 (UTC)
From: isaki@pastel-flower.jp
Reply-To: isaki@pastel-flower.jp
To: gnats-bugs@NetBSD.org
Subject: FREM emulation of m68k FPE is wrong
X-Send-Pr-Version: www-1.0
>Number: 47810
>Category: kern
>Synopsis: FREM emulation of m68k FPE is wrong
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: kern-bug-people
>State: closed
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Thu May 09 05:30:00 +0000 2013
>Closed-Date: Sat May 11 12:56:47 +0000 2013
>Last-Modified: Sat May 11 12:56:47 +0000 2013
>Originator: Tetsuya Isaki
>Release: NetBSD/x68k
>Organization:
>Environment:
NetBSD 6.99.19 x68k
>Description:
The FREM emulation of m68k FPE is wrong at several values.
>How-To-Repeat:
% dmesg | grep FPU
X68030 (m68030 CPU/MMU, emulator FPU, 29MHz clock) on XM6i v0.41
% cat main.c
#include<stdio.h>
extern double my_frem(double, double);
int main()
{
double x;
double y = 4.0;
for (x = 0.0; x > -5.0; x -= 1.0) {
printf("FREM(%g, %g) = %g\n", x, y, my_frem(x, y));
}
}
% cat frem_s.s
.text
.even
.globl my_frem
.type my_frem,@function
my_frem:
fmoved %sp@(4),%fp0
fremd %sp@(12),%fp0
rts
% gcc -o frem main.c frem_s.s
% ./frem
FREM(0, 4) = -4 <-- NG!
FREM(-1, 4) = -1
FREM(-2, 4) = -2
FREM(-3, 4) = -7 <-- NG!
FREM(-4, 4) = -0
%
FREM(0, 4) should be 0 but it returns -4,
FREM(-3,4) should be 1 but it returns -7.
>Fix:
I have and I will commit it soon.
This PR is just for a record.
>Release-Note:
>Audit-Trail:
From: "Tetsuya Isaki" <isaki@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc:
Subject: PR/47810 CVS commit: src/sys/arch/m68k/fpe
Date: Sat, 11 May 2013 12:52:43 +0000
Module Name: src
Committed By: isaki
Date: Sat May 11 12:52:43 UTC 2013
Modified Files:
src/sys/arch/m68k/fpe: fpu_rem.c
Log Message:
Revise the algorithm after Step3.
almost written by Y.Sugahara and minor modify by me.
This works for all input of FMOD/FREM and of course solves PR/47810.
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/sys/arch/m68k/fpe/fpu_rem.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
State-Changed-From-To: open->closed
State-Changed-By: isaki@NetBSD.org
State-Changed-When: Sat, 11 May 2013 12:56:47 +0000
State-Changed-Why:
Fixed.
>Unformatted:
(Contact us)
$NetBSD: query-full-pr,v 1.39 2013/11/01 18:47:49 spz Exp $
$NetBSD: gnats_config.sh,v 1.8 2006/05/07 09:23:38 tsutsui Exp $
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