81 lines
2.8 KiB
C
81 lines
2.8 KiB
C
/* strtask.c - Intel nanokernel APIs to start a task */
|
|
|
|
/*
|
|
* Copyright (c) 2010-2014 Wind River Systems, Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
/*
|
|
* DESCRIPTION
|
|
* Intel-specific parts of start_task(). Only FP functionality currently.
|
|
*/
|
|
|
|
#ifdef CONFIG_MICROKERNEL
|
|
|
|
#include <start_task_arch.h>
|
|
|
|
/*
|
|
* The following IA-32-specific task group is used for tasks that use SSE
|
|
* instructions. It is *not* formally reserved by SysGen for this purpose.
|
|
* See comments in thread.c regarding the use of SSE_GROUP, and comments
|
|
* in task.h regarding task groups reserved by SysGen.
|
|
*
|
|
* This identifier corresponds to the first user-defined task group.
|
|
* It must be updated if any changes are made to the reserved groups.
|
|
*/
|
|
|
|
#define SSE_GROUP 0x10
|
|
|
|
/**
|
|
* @brief Intel-specific parts of task initialization
|
|
*
|
|
* @param X pointer to task control block
|
|
* @param pOpt thread options container
|
|
*
|
|
* @return N/A
|
|
*/
|
|
|
|
void _StartTaskArch(struct k_task *X, unsigned int *pOpt)
|
|
{
|
|
/*
|
|
* The IA-32 nanokernel implementation uses the USE_FP bit in the
|
|
* struct tcs->flags structure as a "dirty bit". The USE_FP flag bit
|
|
* will be set whenever a thread uses any non-integer capability,
|
|
* whether it's just the x87 FPU capability, SSE instructions, or a
|
|
* combination of both. The USE_SSE flag bit will only be set if a
|
|
* thread uses SSE instructions.
|
|
*
|
|
* However, callers of fiber_fiber_start(), task_fiber_start(), or even
|
|
* _new_thread() don't need to follow the protocol used by the IA-32
|
|
* nanokernel w.r.t. managing the struct tcs->flags field. If a thread
|
|
* will be utilizing just the x87 FPU capability, then the USE_FP
|
|
* option bit is specified. If a thread will be utilizing SSE
|
|
* instructions (and possibly x87 FPU capability), then only the
|
|
* USE_SSE option bit needs to be specified.
|
|
*
|
|
* Likewise, the placement of tasks into "groups" doesn't need to follow
|
|
* the protocol used by the IA-32 nanokernel w.r.t. managing the
|
|
* struct tcs->flags field. If a task will utilize just the x87 FPU
|
|
* capability, then the task only needs to be placed in the FPU_GROUP
|
|
* group. If a task utilizes SSE instructions (and possibly x87 FPU
|
|
* capability), then the task only needs to be placed in the SSE_GROUP
|
|
* group.
|
|
*/
|
|
|
|
*pOpt |= (X->group & SSE_GROUP) ? USE_SSE
|
|
: (X->group & FPU_GROUP) ? USE_FP : 0;
|
|
}
|
|
|
|
#endif /* CONFIG_MICROKERNEL */
|