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/*
* Copyright (c) 2013-2014 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.
*/
/**
* @file
* @brief Full C support initialization
*
*
* Initialization of full C support: zero the .bss, copy the .data if XIP,
* call _Cstart().
*
* Stack is available in this module, but not the global data/bss until their
* initialization is performed.
*/
#include <kernel.h>
#include <stdint.h>
#include <toolchain.h>
#include <linker-defs.h>
#include <nano_internal.h>
#ifdef CONFIG_XIP
static inline void relocate_vector_table(void) { /* do nothing */ }
#else
static inline void relocate_vector_table(void)
{
/* vector table is already in SRAM, just point to it */
_scs_relocate_vector_table((void *)CONFIG_SRAM_BASE_ADDRESS);
}
#endif
#ifdef CONFIG_FLOAT
static inline void enable_floating_point(void)
{
/*
* Upon reset, the Co-Processor Access Control Register is 0x00000000.
* Enable CP10 and CP11 coprocessors to enable floating point.
*/
__scs.cpacr.val = (_SCS_CPACR_CP10_FULL_ACCESS |
_SCS_CPACR_CP11_FULL_ACCESS);
/*
* Upon reset, the FPU Context Control Register is 0xC0000000
* (both Automatic and Lazy state preservation is enabled).
* Disable lazy state preservation so the volatile FP registers are
* always saved on exception.
*/
__scs.fpu.ccr.val = (_SCS_FPU_CCR_ASPEN_ENABLE |
_SCS_FPU_CCR_LSPEN_DISABLE);
/*
* Although automatic state preservation is enabled, the processor
* does not automatically save the volatile FP registers until they
* have first been touched. Perform a dummy move operation so that
* the stack frames are created as expected before any task or fiber
* context switching can occur.
*/
__asm__ volatile(
"vmov s0, s0;\n\t"
"dsb;\n\t"
"isb;\n\t"
);
}
#else
static inline void enable_floating_point(void)
{
}
#endif
extern FUNC_NORETURN void _Cstart(void);
/**
*
* @brief Prepare to and run C code
*
* This routine prepares for the execution of and runs C code.
*
* @return N/A
*/
void _PrepC(void)
{
relocate_vector_table();
enable_floating_point();
_bss_zero();
_data_copy();
_Cstart();
CODE_UNREACHABLE;
}
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