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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
MODULE ?chcoreasm_v6m
AAPCS INTERWORK, VFP_COMPATIBLE
PRESERVE8
/*
* Imports the Cortex-Mx parameters header and performs the same calculations
* done in chcore.h.
*/
#include "cmparams.h"
#define CORTEX_PRIORITY_MASK(n) ((n) << (8 - CORTEX_PRIORITY_BITS))
EXTCTX_SIZE SET 32
CONTEXT_OFFSET SET 12
SECTION .text:CODE:NOROOT(2)
EXTERN chThdExit
EXTERN chSchIsRescRequiredExI
EXTERN chSchDoRescheduleI
EXTERN _port_saved_pc
EXTERN _port_irq_nesting
THUMB
/*
* Performs a context switch between two threads.
*/
PUBLIC _port_switch
_port_switch:
push {r4, r5, r6, r7, lr}
mov r4, r8
mov r5, r9
mov r6, r10
mov r7, r11
push {r4, r5, r6, r7}
mov r3, sp
str r3, [r1, #CONTEXT_OFFSET]
ldr r3, [r0, #CONTEXT_OFFSET]
mov sp, r3
pop {r4, r5, r6, r7}
mov r8, r4
mov r9, r5
mov r10, r6
mov r11, r7
pop {r4, r5, r6, r7, pc}
/*
* Start a thread by invoking its work function.
* If the work function returns @p chThdExit() is automatically invoked.
*/
PUBLIC _port_thread_start
_port_thread_start:
cpsie i
mov r0, r5
blx r4
bl chThdExit
/*
* Post-IRQ switch code.
* Exception handlers return here for context switching.
*/
PUBLIC _port_switch_from_isr
_port_switch_from_isr:
/* Note, saves r4 to make space for the PC.*/
push {r0, r1, r2, r3, r4}
mrs r0, APSR
mov r1, r12
push {r0, r1, lr}
ldr r0, =_port_saved_pc
ldr r0, [r0]
adds r0, r0, #1
str r0, [sp, #28]
bl chSchDoRescheduleI
pop {r0, r1, r2}
mov r12, r1
msr APSR, r0
mov lr, r2
pop {r0, r1, r2, r3}
cpsie i
pop {pc}
/*
* Reschedule verification and setup after an IRQ.
*/
PUBLIC _port_irq_epilogue
_port_irq_epilogue:
push {r4, lr}
cpsid i
ldr r2, =_port_irq_nesting
ldr r3, [r2]
subs r3, r3, #1
str r3, [r2]
cmp r3, #0
beq skipexit
notrequired
cpsie i
pop {r4, pc}
skipexit
bl chSchIsRescRequiredExI
cmp r0, #0
beq notrequired
mrs r1, PSP
ldr r2, =_port_saved_pc
ldr r3, [r1, #24]
str r3, [r2]
ldr r3, =_port_switch_from_isr
str r3, [r1, #24]
pop {r4, pc}
END
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