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2019-06-03Merge tag 'nds32-for-linux-5.2-rc3' of ↵Linus Torvalds14-5/+381
git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux Pull nds32 fixes from Greentime Hu: - fix warning for math-emu - fix nds32 fpu exception handling - fix nds32 fpu emulation implementation * tag 'nds32-for-linux-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux: nds32: add new emulations for floating point instruction nds32: Avoid IEX status being incorrectly modified math-emu: Use statement expressions to fix Wshift-count-overflow warning
2019-05-31nds32: add new emulations for floating point instructionVincent Chen14-5/+381
The existing floating point emulations is only available for floating instruction that possibly issue denormalized input and underflow exceptions. These existing FPU emulations are not sufficient when IEx Trap is enabled because some floating point instructions only issue inexact exception. This patch adds the emulations of such floating point instructions. Signed-off-by: Vincent Chen <vincentc@andestech.com> Acked-by: Greentime Hu <greentime@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner1-0/+1
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-22nds32: support denormalized result through FP emulatorVincent Chen1-0/+5
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>
2018-11-22nds32: Support FP emulationVincent Chen18-0/+737
The Andes FPU coprocessor does not support denormalized number handling. According to the specification, FPU generates a denorm input exception that requires the kernel to deal with this instrution operation when it encounters denormalized operands. Hence an nds32 FPU ISA emulator in the kernel is required to meet requirement. Signed-off-by: Vincent Chen <vincentc@andestech.com> Signed-off-by: Nickhu <nickhu@andestech.com> Acked-by: Greentime Hu <greentime@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com>