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path: root/arch/sh/math-emu/math.c
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2010-01-13sh: Move over to dynamically allocated FPU context.Paul Mundt
This follows the x86 xstate changes and implements a task_xstate slab cache that is dynamically sized to match one of hard FP/soft FP/FPU-less. This also tidies up and consolidates some of the SH-2A/SH-4 FPU fragmentation. Now fpu state restorers are commonly defined, with the init_fpu()/fpu_init() mess reworked to follow the x86 convention. The fpu_init() register initialization has been replaced by xstate setup followed by writing out to hardware via the standard restore path. As init_fpu() now performs a slab allocation a secondary lighterweight restorer is also introduced for the context switch. In the future the DSP state will be rolled in here, too. More work remains for math emulation and the SH-5 FPU, which presently uses its own special (UP-only) interfaces. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-11-24sh: Minor optimisations to FPU handlingStuart Menefy
A number of small optimisations to FPU handling, in particular: - move the task USEDFPU flag from the thread_info flags field (which is accessed asynchronously to the thread) to a new status field, which is only accessed by the thread itself. This allows locking to be removed in most cases, or can be reduced to a preempt_lock(). This mimics the i386 behaviour. - move the modification of regs->sr and thread_info->status flags out of save_fpu() to __unlazy_fpu(). This gives the compiler a better chance to optimise things, as well as making save_fpu() symmetrical with restore_fpu() and init_fpu(). - implement prepare_to_copy(), so that when creating a thread, we can unlazy the FPU prior to copying the thread data structures. Also make sure that the FPU is disabled while in the kernel, in particular while booting, and for newly created kernel threads, In a very artificial benchmark, the execution time for 2500000 context switches was reduced from 50 to 45 seconds. Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-06-11sh: Fix up the math-emu build.Paul Mundt
math-emu wasn't converted for the trap_no/errno_code changes, get it building again. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-05-21spelling fixes: arch/sh/Simon Arlott
Spelling fixes in arch/sh/. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-10-03sh: Kill off remaining config.h references.Paul Mundt
A few of these managed to sneak back in, get rid of them once and for all. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-09-27sh: math-emu supportTakashi YOSHII
This implements initial math-emu support, aimed primarily at SH-3. Signed-off-by: Takashi YOSHII <takasi-y@ops.dti.ne.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>