Commit Graph

3 Commits

Author SHA1 Message Date
Nishad Kamdar
7f9ea6b799 nds32: Use the correct style for SPDX License Identifier
This patch corrects the SPDX License Identifier style
in the nds32 Hardware Architecture related files.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
2019-05-07 17:52:09 +08:00
Vincent Chen
44e92e0364 nds32: support denormalized result through FP emulator
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>
2018-11-22 18:13:27 +08:00
Greentime Hu
1932fbe36e nds32: System calls handling
This patch adds support for system calls.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
2018-02-22 10:44:33 +08:00