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/* * Copyright (c) 2013-2014 Wind River Systems, Inc. * * SPDX-License-Identifier: Apache-2.0 */ /** * @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> #include <arch/arm/cortex_m/cmsis.h> #ifdef CONFIG_ARMV6_M static inline void relocate_vector_table(void) { /* do nothing */ } #elif defined(CONFIG_ARMV7_M) #ifdef CONFIG_XIP #define VECTOR_ADDRESS (CONFIG_FLASH_BASE_ADDRESS + CONFIG_TEXT_SECTION_OFFSET) #else #define VECTOR_ADDRESS CONFIG_SRAM_BASE_ADDRESS #endif static inline void relocate_vector_table(void) { SCB->VTOR = VECTOR_ADDRESS & SCB_VTOR_TBLOFF_Msk; __DSB(); __ISB(); } #else #error Unknown ARM architecture #endif /* CONFIG_ARMv6_M */ #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. */ SCB->CPACR |= CPACR_CP10_FULL_ACCESS | 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. */ FPU->FPCCR = FPU_FPCCR_ASPEN_Msk; /* FPU_FPCCR_LSPEN = 0 */ /* * 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; } |