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RL-ARM User's Guide
RL-RTX Overview 
Product Description Product Specification Technical Data Timing Specifications Advantages 
Your First RTX Application 
Theory of Operation Timer Tick Interrupt System Task Manager Task Management Idle Task System Resources Scheduling Options Pre-emptive Scheduling Round-Robin Scheduling Cooperative Multitasking Priority Inversion Stack Management User Timers Interrupt Functions Configuring RTX Kernel Basic RTX Configuration Tasks Stack Size Stack Checking Run in Privileged Mode Hardware Timer Round-Robin Multitasking User Timers FIFO Queue Buffer Error Function Idle Task Advanced RTX Configuration HW Resources Required Configuration Macros Library Files Using RTX Kernel Writing Programs Include Files Defining Tasks Multiple Instances External References Using a Mailbox SWI Functions SVC Functions Debugging System Info Task Info Event Viewer Usage Hints ARM Version Cortex Version Create New RTX Application Function Reference Event Flag Management Routines Mailbox Management Routines Memory Allocation Routines Mutex Management Routines Semaphore Management Routines System Functions Task Management Routines Time Management Routines User Timer Management Routines 
RL-FlashFS 
RL-TCPnet RL-CAN RL-USB Example Programs Library Reference AppendixStack Size
The stack usage of a particular task depends on its amount of local automatic variables and the number of subroutine levels. Interrupt functions do not use the stack of the interrupted task.
- OS_STKSIZE specifies the amount of RAM allocated for the stack of each task. Stack size is defined in U32 (unsigned int). However, Configuration Wizard converts the specified size and displays it in bytes. Stack size with the following define is 400 bytes.
#define OS_STKSIZE 100
On the full context task switch, the RTX kernel stores all ARM registers on the stack. Full task context storing requires 64 bytes of stack.
- The Cortex-M4 with Hardware Floating Point, needs additional 136 bytes on stack for storing VFP registers. This means the total size of the full context store for Cortex-M4 with FP is 200 bytes.
- The Cortex-M4 tasks, where the Floating Point arithmetics is not used, do not store the additional VFP registers on context save. This means, they do not need additional 136 bytes on the stack. The full context store for tasks with no Floating Point calculations is still 64 bytes.
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