92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/*
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* Copyright (c) 2013-2014 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Full C support initialization
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*
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*
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* Initialization of full C support: zero the .bss, copy the .data if XIP,
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* call _Cstart().
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*
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* Stack is available in this module, but not the global data/bss until their
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* initialization is performed.
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*/
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#include <kernel.h>
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#include <stdint.h>
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#include <toolchain.h>
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#include <linker-defs.h>
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#include <nano_internal.h>
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#ifdef CONFIG_XIP
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static inline void relocate_vector_table(void) { /* do nothing */ }
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#else
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static inline void relocate_vector_table(void)
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{
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/* vector table is already in SRAM, just point to it */
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_scs_relocate_vector_table((void *)CONFIG_SRAM_BASE_ADDRESS);
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}
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#endif
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#ifdef CONFIG_FLOAT
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static inline void enable_floating_point(void)
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{
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/*
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* Upon reset, the Co-Processor Access Control Register is 0x00000000.
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* Enable CP10 and CP11 coprocessors to enable floating point.
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*/
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__scs.cpacr.val = (_SCS_CPACR_CP10_FULL_ACCESS |
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_SCS_CPACR_CP11_FULL_ACCESS);
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/*
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* Upon reset, the FPU Context Control Register is 0xC0000000
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* (both Automatic and Lazy state preservation is enabled).
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* Disable lazy state preservation so the volatile FP registers are
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* always saved on exception.
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*/
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__scs.fpu.ccr.val = (_SCS_FPU_CCR_ASPEN_ENABLE |
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_SCS_FPU_CCR_LSPEN_DISABLE);
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/*
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* Although automatic state preservation is enabled, the processor
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* does not automatically save the volatile FP registers until they
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* have first been touched. Perform a dummy move operation so that
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* the stack frames are created as expected before any task or fiber
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* context switching can occur.
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*/
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__asm__ volatile(
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"vmov s0, s0;\n\t"
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"dsb;\n\t"
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"isb;\n\t"
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);
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}
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#else
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static inline void enable_floating_point(void)
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{
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}
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#endif
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extern FUNC_NORETURN void _Cstart(void);
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/**
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*
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* @brief Prepare to and run C code
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*
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* This routine prepares for the execution of and runs C code.
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*
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* @return N/A
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*/
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void _PrepC(void)
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{
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relocate_vector_table();
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enable_floating_point();
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_bss_zero();
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_data_copy();
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_Cstart();
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CODE_UNREACHABLE;
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}
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