blob: 787d37fbfd9e3e44736f42473f81f234fccae430 [file] [log] [blame]
// Copyright 2020 The Pigweed Authors
// 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
// 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.
#include "pw_boot_armv7m/boot.h"
#include "pw_malloc/malloc.h"
#include "pw_preprocessor/compiler.h"
#include "pw_sys_io_baremetal_stm32f429/init.h"
// Note that constexpr is used inside of this function instead of using a static
// constexpr or declaring it outside of this function in an anonymous namespace,
// because constexpr makes it available for the compiler to evaluate during
// compile time but does NOT require it to be evaluated at compile time and we
// have to be incredibly careful that this does not end up in the .data section.
void pw_boot_PreStaticMemoryInit() {
// TODO(pwbug/17): Optionally enable Replace when Pigweed config system is
// added.
// Enable FPU if built using hardware FPU instructions.
// CPCAR mask that enables FPU. (ARMv7-M Section B3.2.20)
constexpr uint32_t kFpuEnableMask = (0xFu << 20);
// Memory mapped register to enable FPU. (ARMv7-M Section B3.2.2, Table B3-4)
volatile uint32_t& arm_v7m_cpacr =
*reinterpret_cast<volatile uint32_t*>(0xE000ED88u);
arm_v7m_cpacr |= kFpuEnableMask;
// Ensure the FPU configuration is committed and enabled before continuing and
// potentially executing any FPU instructions, however rare that may be during
// startup.
asm volatile(
" dsb \n"
" isb \n"
// clang-format off
: /*output=*/
: /*input=*/
: /*clobbers=*/"memory"
// clang-format on
void pw_boot_PreStaticConstructorInit() {
void pw_boot_PreMainInit() { pw_sys_io_Init(); }
PW_NO_RETURN void pw_boot_PostMain() {
// In case main() returns, just sit here until the device is reset.
while (true) {