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 namespace pw::interrupt { 19 20 #if defined(PW_INTERRUPT_CORTEX_M_ARMV6M) || \ 21 defined(PW_INTERRUPT_CORTEX_M_ARMV7M) || \ 22 defined(PW_INTERRUPT_CORTEX_M_ARMV8M) InInterruptContext()23inline bool InInterruptContext() { 24 // ARMv7M Reference manual section B1.4.2 describes how the Interrupt 25 // Program Status Register (IPSR) is zero if there is no exception (interrupt) 26 // being processed. 27 uint32_t ipsr; 28 asm volatile("MRS %0, ipsr" : "=r"(ipsr)); 29 return ipsr != 0; 30 } 31 #else 32 #error "Please select an architecture specific backend." 33 #endif 34 35 } // namespace pw::interrupt 36