1 // Copyright 2020 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <cstdint> 17 18 #include "pw_preprocessor/arch.h" 19 20 namespace pw::interrupt { 21 22 #if !_PW_ARCH_ARM_CORTEX_M 23 #error You can only build this for ARM Cortex-M architectures. If you are \ 24 trying to do this and are still seeing this error, see \ 25 pw_preprocessor/arch.h 26 #endif // !_PW_ARCH_ARM_CORTEX_M 27 28 #if _PW_ARCH_ARM_V6M || _PW_ARCH_ARM_V7M || _PW_ARCH_ARM_V7EM || \ 29 _PW_ARCH_ARM_V8M_BASELINE || _PW_ARCH_ARM_V8M_MAINLINE || \ 30 _PW_ARCH_ARM_V8_1M_MAINLINE InInterruptContext()31inline bool InInterruptContext() { 32 // ARMv7M Reference manual section B1.4.2 describes how the Interrupt 33 // Program Status Register (IPSR) is zero if there is no exception (interrupt) 34 // being processed. 35 uint32_t ipsr; 36 asm volatile("MRS %0, ipsr" : "=r"(ipsr)); 37 return ipsr != 0; 38 } 39 #else 40 #error "Your selected ARM Cortex-M arch is not yet supported by this module." 41 #endif 42 43 } // namespace pw::interrupt 44