/**************************************************************************/ /* */ /* Copyright (c) Microsoft Corporation. All rights reserved. */ /* */ /* This software is licensed under the Microsoft Software License */ /* Terms for Microsoft Azure RTOS. Full text of the license can be */ /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */ /* and in the root directory of this software. */ /* */ /**************************************************************************/ /**************************************************************************/ /**************************************************************************/ /** */ /** ThreadX Component */ /** */ /** Thread */ /** */ /**************************************************************************/ /**************************************************************************/ #ifdef TX_INCLUDE_USER_DEFINE_FILE #include "tx_user.h" #endif .global _tx_thread_execute_ptr .global _tx_thread_current_ptr .global _tx_timer_time_slice /* Define the 16-bit Thumb mode veneer for _tx_thread_schedule for applications calling this function from to 16-bit Thumb mode. */ .text .align 2 .global $_tx_thread_schedule .type $_tx_thread_schedule,function $_tx_thread_schedule: .thumb BX pc // Switch to 32-bit mode NOP // .arm STMFD sp!, {lr} // Save return address BL _tx_thread_schedule // Call _tx_thread_schedule function LDMFD sp!, {lr} // Recover saved return address BX lr // Return to 16-bit caller .text .align 2 /**************************************************************************/ /* */ /* FUNCTION RELEASE */ /* */ /* _tx_thread_schedule ARMv7-A */ /* 6.3.0 */ /* 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 */ /* 10-15-2021 William E. Lamie Modified comment(s), added */ /* execution profile support, */ /* resulting in version 6.1.9 */ /* 04-25-2022 Zhen Kong Updated comments, */ /* resulting in version 6.1.11 */ /* 10-31-2023 Tiejun Zhou Modified comment(s), added */ /* #include tx_user.h, */ /* resulting in version 6.3.0 */ /* */ /**************************************************************************/ .global _tx_thread_schedule .type _tx_thread_schedule,function _tx_thread_schedule: /* Enable interrupts. */ #ifdef TX_ENABLE_FIQ_SUPPORT CPSIE if // Enable IRQ and FIQ interrupts #else CPSIE i // Enable IRQ interrupts #endif /* Wait for a thread to execute. */ 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 /* Yes! We have a thread to execute. Lockout interrupts and transfer control to it. */ #ifdef TX_ENABLE_FIQ_SUPPORT CPSID if // Disable IRQ and FIQ interrupts #else CPSID i // Disable IRQ interrupts #endif /* Setup the current thread pointer. */ 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. */ 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. */ 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 #if (defined(TX_ENABLE_EXECUTION_CHANGE_NOTIFY) || defined(TX_EXECUTION_PROFILE_ENABLE)) /* Call the thread entry function to indicate the thread is executing. */ MOV r5, r0 // Save r0 BL _tx_execution_thread_enter // Call the thread execution enter function MOV r0, r5 // Restore r0 #endif /* Determine if an interrupt frame or a synchronous task suspension frame is present. */ LDMIA sp!, {r4, r5} // Pickup the stack type and saved CPSR CMP r4, #0 // Check for synchronous context switch BEQ _tx_solicited_return MSR SPSR_cxsf, r5 // Setup SPSR for return #ifdef TX_ENABLE_VFP_SUPPORT LDR r1, [r0, #144] // Pickup the VFP enabled flag CMP r1, #0 // Is the VFP enabled? BEQ _tx_skip_interrupt_vfp_restore // No, skip VFP interrupt restore VLDMIA sp!, {D0-D15} // Recover D0-D15 VLDMIA sp!, {D16-D31} // Recover D16-D31 LDR r4, [sp], #4 // Pickup FPSCR VMSR FPSCR, r4 // Restore FPSCR _tx_skip_interrupt_vfp_restore: #endif LDMIA sp!, {r0-r12, lr, pc}^ // Return to point of thread interrupt _tx_solicited_return: #ifdef TX_ENABLE_VFP_SUPPORT LDR r1, [r0, #144] // Pickup the VFP enabled flag CMP r1, #0 // Is the VFP enabled? BEQ _tx_skip_solicited_vfp_restore // No, skip VFP solicited restore VLDMIA sp!, {D8-D15} // Recover D8-D15 VLDMIA sp!, {D16-D31} // Recover D16-D31 LDR r4, [sp], #4 // Pickup FPSCR VMSR FPSCR, r4 // Restore FPSCR _tx_skip_solicited_vfp_restore: #endif MSR CPSR_cxsf, r5 // Recover CPSR LDMIA sp!, {r4-r11, lr} // Return to thread synchronously #ifdef __THUMB_INTERWORK BX lr // Return to caller #else MOV pc, lr // Return to caller #endif #ifdef TX_ENABLE_VFP_SUPPORT .global tx_thread_vfp_enable .type tx_thread_vfp_enable,function tx_thread_vfp_enable: MRS r2, CPSR // Pickup the CPSR #ifdef TX_ENABLE_FIQ_SUPPORT CPSID if // Enable IRQ and FIQ interrupts #else CPSID i // Enable IRQ interrupts #endif LDR r0, =_tx_thread_current_ptr // Build current thread pointer address LDR r1, [r0] // Pickup current thread pointer CMP r1, #0 // Check for NULL thread pointer BEQ __tx_no_thread_to_enable // If NULL, skip VFP enable MOV r0, #1 // Build enable value STR r0, [r1, #144] // Set the VFP enable flag (tx_thread_vfp_enable field in TX_THREAD) __tx_no_thread_to_enable: MSR CPSR_cxsf, r2 // Recover CPSR BX LR // Return to caller .global tx_thread_vfp_disable .type tx_thread_vfp_disable,function tx_thread_vfp_disable: MRS r2, CPSR // Pickup the CPSR #ifdef TX_ENABLE_FIQ_SUPPORT CPSID if // Enable IRQ and FIQ interrupts #else CPSID i // Enable IRQ interrupts #endif LDR r0, =_tx_thread_current_ptr // Build current thread pointer address LDR r1, [r0] // Pickup current thread pointer CMP r1, #0 // Check for NULL thread pointer BEQ __tx_no_thread_to_disable // If NULL, skip VFP disable MOV r0, #0 // Build disable value STR r0, [r1, #144] // Clear the VFP enable flag (tx_thread_vfp_enable field in TX_THREAD) __tx_no_thread_to_disable: MSR CPSR_cxsf, r2 // Recover CPSR BX LR // Return to caller #endif