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/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Thread */
/** */
/**************************************************************************/
/**************************************************************************/
/* #define TX_SOURCE_CODE */
/* Include necessary system files. */
/* #include "tx_api.h"
#include "tx_thread.h"
#include "tx_timer.h" */
#ifdef TX_ENABLE_FIQ_SUPPORT
ENABLE_INTS = 0xC0 # IRQ & FIQ Interrupts enabled mask
#else
ENABLE_INTS = 0x80 # IRQ Interrupts enabled mask
#endif
.text
.align 4
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_schedule Cortex-R4/Green Hills */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function waits for a thread control block pointer to appear in */
/* the _tx_thread_execute_ptr variable. Once a thread pointer appears */
/* in the variable, the corresponding thread is resumed. */
/* */
/* INPUT */
/* */
/* None */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _tx_initialize_kernel_enter ThreadX entry function */
/* _tx_thread_system_return Return to system from thread */
/* _tx_thread_context_restore Restore thread's context */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 09-30-2020 William E. Lamie Initial Version 6.1 */
/* */
/**************************************************************************/
/* VOID _tx_thread_schedule(VOID)
{ */
.globl _tx_thread_schedule
_tx_thread_schedule:
/* Enable interrupts. */
#ifdef TX_BEFORE_ARMV6
MRS r2, CPSR # Pickup CPSR
BIC r0, r2, ENABLE_INTS # Clear the disable bit(s)
MSR CPSR_c, r0 # Enable interrupts
#else
#ifdef TX_ENABLE_FIQ_SUPPORT
CPSIE if # Enable IRQ and FIQ interrupts
#else
CPSIE i # Enable IRQ interrupts
#endif
#endif
/* Wait for a thread to execute. */
/* do
{ */
LDR r1, =_tx_thread_execute_ptr # Address of thread execute ptr
__tx_thread_schedule_loop:
LDR r0, [r1] # Pickup next thread to execute
CMP r0, 0 # Is it NULL?
BEQ __tx_thread_schedule_loop # If so, keep looking for a thread
/* }
while(_tx_thread_execute_ptr == TX_NULL); */
/* Yes! We have a thread to execute. Lockout interrupts and
transfer control to it. */
#ifdef TX_BEFORE_ARMV6
MSR CPSR_c, r2 # Disable interrupts
#else
#ifdef TX_ENABLE_FIQ_SUPPORT
CPSID if # Disable IRQ and FIQ interrupts
#else
CPSID i # Disable IRQ interrupts
#endif
#endif
/* Setup the current thread pointer. */
/* _tx_thread_current_ptr = _tx_thread_execute_ptr; */
#ifdef TX_ENABLE_EVENT_LOGGING
MOV v1, r0 # Save temp register in non-volatile register
BL _tx_el_thread_running # Call event logging routine
MOV r0, v1 # Restore temp register
#endif
LDR r1, =_tx_thread_current_ptr # Pickup address of current thread
STR r0, [r1] # Setup current thread pointer
/* Increment the run count for this thread. */
/* _tx_thread_current_ptr -> tx_thread_run_count++; */
LDR r2, [r0, 4] # Pickup run counter
LDR r3, [r0, 24] # Pickup time-slice for this thread
ADD r2, r2, 1 # Increment thread run-counter
STR r2, [r0, 4] # Store the new run counter
/* Setup time-slice, if present. */
/* _tx_timer_time_slice = _tx_thread_current_ptr -> tx_thread_time_slice; */
LDR r2, =_tx_timer_time_slice # Pickup address of time slice
/* # variable */
LDR sp, [r0, 8] # Switch stack pointers
STR r3, [r2] # Setup time-slice
/* Switch to the thread's stack. */
/* sp = _tx_thread_execute_ptr -> tx_thread_stack_ptr; */
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
/* Call the thread entry function to indicate the thread is executing. */
BL _tx_execution_thread_enter # Call the thread execution enter function
#endif
/* Determine if an interrupt frame or a synchronous task suspension frame
is present. */
LDMIA sp!, {r0, r1} # Pickup the stack type and saved CPSR
MSR SPSR_cxsf, r1 # Setup SPSR for return
CMP r0, 0 # Check for synchronous context switch
LDMNEIA sp!, {r0-r12, lr, pc}^ # If non-zero, return to point of interrupt
/* # in the thread */
LDMIA sp!, {v1-r11, lr} # Otherwise, return to thread synchronously
MSR CPSR_cxsf,r1 # Recover CPSR (r1 is still valid)
RET # Return to caller (Thumb safe)
.type _tx_thread_schedule,$function
.size _tx_thread_schedule,.-_tx_thread_schedule
/* } */
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