mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 11:18:45 +07:00
44e92e0364
Currently, the nds32 FPU dose not support the arithmetic of denormalized
number. When the nds32 FPU finds the result of the instruction is a
denormlized number, the nds32 FPU considers it to be an underflow condition
and rounds the result to an appropriate number. It may causes some loss
of precision. This commit proposes a solution to re-execute the
instruction by the FPU emulator to enhance the precision. To transfer
calculations from user space to kernel space, this feature will enable
the underflow exception trap by default. Enabling this feature may cause
some side effects:
1. Performance loss due to extra FPU exception
2. Need another scheme to control real underflow trap
A new parameter, UDF_trap, which is belong to FPU context is used
to control underflow trap.
User can configure this feature via CONFIG_SUPPORT_DENORMAL_ARITHMETIC
Signed-off-by: Vincent Chen <vincentc@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
20 lines
379 B
C
20 lines
379 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
// Copyright (C) 2005-2017 Andes Technology Corporation
|
|
|
|
#ifndef __ASM_AUXVEC_H
|
|
#define __ASM_AUXVEC_H
|
|
|
|
/*
|
|
* This entry gives some information about the FPU initialization
|
|
* performed by the kernel.
|
|
*/
|
|
#define AT_FPUCW 18 /* Used FPU control word. */
|
|
|
|
|
|
/* VDSO location */
|
|
#define AT_SYSINFO_EHDR 33
|
|
|
|
#define AT_VECTOR_SIZE_ARCH 1
|
|
|
|
#endif
|