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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/>.
*/
/**
* @file ARM7/chcoreasm.s
* @brief ARM7 architecture port low level code.
* @addtogroup ARM7_CORE
* @{
*/
/** @cond never */
#include <chconf.h>
.set MODE_USR, 0x10
.set MODE_FIQ, 0x11
.set MODE_IRQ, 0x12
.set MODE_SVC, 0x13
.set MODE_ABT, 0x17
.set MODE_UND, 0x1B
.set MODE_SYS, 0x1F
.equ I_BIT, 0x80
.equ F_BIT, 0x40
.text
/*
* Interrupt enable/disable functions, only present if there is THUMB code in
* the system because those are inlined in ARM code.
*/
#ifdef THUMB_PRESENT
.balign 16
.code 16
.thumb_func
.global _port_disable_thumb
_port_disable_thumb:
mov r3, pc
bx r3
.code 32
mrs r3, CPSR
orr r3, #I_BIT
msr CPSR_c, r3
orr r3, #F_BIT
msr CPSR_c, r3
bx lr
.balign 16
.code 16
.thumb_func
.global _port_suspend_thumb
_port_suspend_thumb:
.thumb_func
.global _port_lock_thumb
_port_lock_thumb:
mov r3, pc
bx r3
.code 32
msr CPSR_c, #MODE_SYS | I_BIT
bx lr
.balign 16
.code 16
.thumb_func
.global _port_enable_thumb
_port_enable_thumb:
.thumb_func
.global _port_unlock_thumb
_port_unlock_thumb:
mov r3, pc
bx r3
.code 32
msr CPSR_c, #MODE_SYS
bx lr
#endif
.balign 16
#ifdef THUMB_PRESENT
.code 16
.thumb_func
.global _port_switch_thumb
_port_switch_thumb:
mov r2, pc
bx r2
// Jumps into _port_switch_arm in ARM mode
#endif
.code 32
.global _port_switch_arm
_port_switch_arm:
#ifdef CH_CURRP_REGISTER_CACHE
stmfd sp!, {r4, r5, r6, r8, r9, r10, r11, lr}
str sp, [r1, #16]
ldr sp, [r0, #16]
#ifdef THUMB_PRESENT
ldmfd sp!, {r4, r5, r6, r8, r9, r10, r11, lr}
bx lr
#else /* !THUMB_PRESENT */
ldmfd sp!, {r4, r5, r6, r8, r9, r10, r11, pc}
#endif /* !THUMB_PRESENT */
#else /* !CH_CURRP_REGISTER_CACHE */
stmfd sp!, {r4, r5, r6, r7, r8, r9, r10, r11, lr}
str sp, [r1, #12]
ldr sp, [r0, #12]
#ifdef THUMB_PRESENT
ldmfd sp!, {r4, r5, r6, r7, r8, r9, r10, r11, lr}
bx lr
#else /* !THUMB_PRESENT */
ldmfd sp!, {r4, r5, r6, r7, r8, r9, r10, r11, pc}
#endif /* !THUMB_PRESENT */
#endif /* !CH_CURRP_REGISTER_CACHE */
/*
* Common exit point for all IRQ routines, it performs the rescheduling if
* required.
* System stack frame structure after a context switch in the
* interrupt handler:
*
* High +------------+
* | LR_USR | -+
* | R12 | |
* | R3 | |
* | R2 | | External context: IRQ handler frame
* | R1 | |
* | R0 | |
* | PC | | (user code return address)
* | PSR_USR | -+ (user code status)
* | .... | <- mk_DoRescheduleI() stack frame, optimize it for space
* | LR | -+ (system code return address)
* | R11 | |
* | R10 | |
* | R9 | |
* | R8 | | Internal context: mk_SwitchI() frame
* | (R7) | | (optional, see CH_CURRP_REGISTER_CACHE)
* | R6 | |
* | R5 | |
* SP-> | R4 | -+
* Low +------------+
*/
.balign 16
#ifdef THUMB_NO_INTERWORKING
.code 16
.thumb_func
.globl _port_irq_common
_port_irq_common:
bl chSchIsRescRequiredExI
mov lr, pc
bx lr
.code 32
#else /* !THUMB_NO_INTERWORKING */
.code 32
.globl _port_irq_common
_port_irq_common:
bl chSchIsRescRequiredExI
#endif /* !THUMB_NO_INTERWORKING */
cmp r0, #0 // Simply returns if a
ldmeqfd sp!, {r0-r3, r12, lr} // reschedule is not
subeqs pc, lr, #4 // required.
// Saves the IRQ mode registers in the system stack.
ldmfd sp!, {r0-r3, r12, lr} // IRQ stack now empty.
msr CPSR_c, #MODE_SYS | I_BIT
stmfd sp!, {r0-r3, r12, lr} // Registers on System Stack.
msr CPSR_c, #MODE_IRQ | I_BIT
mrs r0, SPSR
mov r1, lr
msr CPSR_c, #MODE_SYS | I_BIT
stmfd sp!, {r0, r1} // Push R0=SPSR, R1=LR_IRQ.
// Context switch.
#ifdef THUMB_NO_INTERWORKING
add r0, pc, #1
bx r0
.code 16
bl chSchDoRescheduleI
mov lr, pc
bx lr
.code 32
#else /* !THUMB_NO_INTERWORKING */
bl chSchDoRescheduleI
#endif /* !THUMB_NO_INTERWORKING */
// Re-establish the IRQ conditions again.
ldmfd sp!, {r0, r1} // Pop R0=SPSR, R1=LR_IRQ.
msr CPSR_c, #MODE_IRQ | I_BIT
msr SPSR_fsxc, r0
mov lr, r1
msr CPSR_c, #MODE_SYS | I_BIT
ldmfd sp!, {r0-r3, r12, lr}
msr CPSR_c, #MODE_IRQ | I_BIT
subs pc, lr, #4
/*
* Threads trampoline code.
* NOTE: The threads always start in ARM mode then switch to the thread-function mode.
*/
.balign 16
.code 32
.globl _port_thread_start
_port_thread_start:
msr CPSR_c, #MODE_SYS
#ifndef THUMB_NO_INTERWORKING
mov r0, r5
mov lr, pc
bx r4
bl chThdExit
#else /* !THUMB_NO_INTERWORKING */
add r0, pc, #1
bx r0
.code 16
mov r0, r5
bl jmpr4
bl chThdExit
jmpr4:
bx r4
#endif /* !THUMB_NO_INTERWORKING */
/** @endcond */
/** @} */
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