QP is an event-driven, RTOS-like, active object framework for microcontrollers, such as mbed. The QP framework provides thread-safe execution of active objects (concurrent state machines) and support both manual and automatic coding of UML statecharts in readable, production-quality C or C++. Automatic code generation of QP code is supported by the free QM modeling tool.
Dependents: qp_hangman qp_dpp qp_blinky
QP/C++ (Quantum Platform in C++) is a lightweight, open source active object (actor) framework for building responsive and modular real-time embedded applications as systems of asynchronous event-driven active objects (actors). The QP/C++ framework is a member of a larger family consisting of QP/C++, QP/C, and QP-nano frameworks, which are all strictly quality controlled, thoroughly documented, and available under GPLv3 with a special Exception for mbed (see http://www.state-machine.com/licensing/QP-mbed_GPL_Exception.txt).
The behavior of active objects is specified in QP/C++ by means of hierarchical state machines (UML statecharts). The framework supports manual coding of UML state machines in C++ as well as automatic code generation by means of the free QM modeling tool (http://www.state-machine.com/qm).
Please see the "QP/C++ Reference Manual" (http://www.state-machine.com/qpcpp) for more information.
Diff: qk_port.s
- Revision:
- 0:064c79e7311a
- Child:
- 5:949864ba515c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/qk_port.s Wed Feb 09 14:46:03 2011 +0000 @@ -0,0 +1,126 @@ +;***************************************************************************** +; Product: QK port to ARM Cortex-M0/M3, mbed ARM assembler, CMSIS-compliant +; Last Updated for Version: 4.1.06 +; Date of the Last Update: Feb 07, 2011 +; +; Q u a n t u m L e a P s +; --------------------------- +; innovating embedded systems +; +; Copyright (C) 2002-2011 Quantum Leaps, LLC. All rights reserved. +; +; This software may be distributed and modified under the terms of the GNU +; General Public License version 2 (GPL) as published by the Free Software +; Foundation and appearing in the file GPL.TXT included in the packaging of +; this file. Please note that GPL Section 2[b] requires that all works based +; on this software must also be made publicly available under the terms of +; the GPL ("Copyleft"). +; +; Alternatively, this software may be distributed and modified under the +; terms of Quantum Leaps commercial licenses, which expressly supersede +; the GPL and are specifically designed for licensees interested in +; retaining the proprietary status of their code. +; +; Contact information: +; Quantum Leaps Web site: http://www.quantum-leaps.com +; e-mail: info@quantum-leaps.com +;***************************************************************************** + AREA QK, CODE, READONLY + + EXPORT QK_init + EXPORT PendSV_Handler ; CMSIS-compliant PendSV exception name + EXPORT SVC_Handler ; CMSIS-compliant SVC exception name + + EXTERN QK_schedule_ ; external references + EXTERN QK_readySet_ ; external references + + +;***************************************************************************** +; +; The QK_init function sets the priorities of SVCall and PendSV exceptions +; to the lowest level possible (0xFF). The function internally disables +; interrupts, but restores the original interrupt lock before exit. +; +;***************************************************************************** +QK_init + MRS r0,PRIMASK ; store the state of the PRIMASK in r0 + CPSID i ; disable interrupts (set PRIMASK) + + LDR r1,=0xE000ED18 ; System Handler Priority Register + LDR r2,[r1,#8] ; load the System 12-15 Priority Register + MOVS r3,#0xFF + LSLS r3,r3,#16 + ORRS r2,r3 ; set PRI_14 (PendSV) to 0xFF + STR r2,[r1,#8] ; write the System 12-15 Priority Register + LDR r2,[r1,#4] ; load the System 8-11 Priority Register + LSLS r3,r3,#8 + ORRS r2,r3 ; set PRI_11 (SVCall) to 0xFF + STR r2,[r1,#4] ; write the System 8-11 Priority Register + + MSR PRIMASK,r0 ; restore the original PRIMASK + BX lr ; return to the caller + + +;***************************************************************************** +; +; The PendSV_Handler exception hanlder is used for handling asynchronous +; preemptions in QK. The use of the PendSV exception is the recommended +; and most efficient method for performing context switches with ARM Cortex. +; +; The PendSV exception should have the lowest priority in the whole system +; (0xFF, see QK_init). All other exeptions and interrupts should have higher +; priority. For example, for NVIC with 2 priority bits all interrupts and +; exceptions must have numerical value of priority lower than 0xC0. In this +; case the interrupt priority levels available to your applications are (in +; the order from the lowest urgency to the highest urgency): 0x80, 0x40, 0x00. +; +; Also, *all* ISRs in the QK application must trigger the PendSV exception +; by calling the QK_ISR_EXIT() macro. +; +; Due to tail-chaining and its lowest priority, the PendSV exception will be +; entered immediately after the exit from the *last* nested interrupt (or +; exception). In QK, this is exactly the time when the QK scheduler needs to +; check for the asynchronous preemptions. +; +;***************************************************************************** +PendSV_Handler + CPSID i ; disable interrupts at processor level + LDR r0,=QK_readySet_ ; load the address of QK_readySet_ + LDRB r0,[r0] ; load the first byte of QK_readySet_ + CMP r0,#0 ; is QK_readySet_ == 0 ? + BEQ.N iret ; if QK_readySet_ == 0, branch to iret + + MOVS r1,#0x01 + LSLS r1,r1,#24 ; make up a task xPSR with only the T bit set + LDR r0,=schedule ; load the address of sched wrapper (new PC) + PUSH {r0-r1} ; push xPSR,PC + SUB sp,sp,#(6*4) ; don't care for lr,r12,r3,r2,r1,r0 + BX lr ; interrupt return to the scheduler + +iret + CPSIE i ; enable interrupts at processor level + BX lr ; interrupt return to the task + +schedule + BL QK_schedule_ ; call the QK scheduler + CPSIE i ; enable interrupts to allow SVCall exception + SVC 0 ; SV exception returns to the preempted task + + +;***************************************************************************** +; +; The SVC_Handler exception handler is used for returning back to the +; interrupted context (task or interrupt). The SVC exception should have +; the lowest priority in the whole system (see QK_init). The SVCall +; exception simply removes its own interrupt stack frame from the stack and +; returns to the preempted task using the interrupt stack frame that must be +; at the top of the stack. +; +;***************************************************************************** +SVC_Handler + ADD sp,sp,#(8*4) ; remove one interrupt frame from the stack + BX lr ; return to the preempted task + + ALIGN ; make sure proper alignment + END + \ No newline at end of file