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/*
* $Id$
*
* This file contains all assembly code for the ARM implementation
* of RTEMS.
*
* Copyright (c) 2007 by Ray Xu, <Rayx.cn@gmail.com>
* Thumb support added.
*
* Copyright (c) 2002 by Advent Networks, Inc.
* Jay Monkman <jmonkman@adventnetworks.com>
*
* COPYRIGHT (c) 2000 Canon Research Centre France SA.
* Emmanuel Raguet, mailto:raguet@crf.canon.fr
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
*/
#include <rtems/asm.h>
#include <rtems/score/cpu_asm.h>
/*
* function declaration macro (start body in ARM mode)
*/
#ifdef __thumb__
#define FUNC_START_ARM(_name_) \
.code 16 ;\
.thumb_func ;\
.globl _name_ ;\
_name_: ;\
bx pc ;\
.code 32 ;\
_name_ ## _ARM:
#else
#define FUNC_START_ARM(_name_) \
.globl _name_; \
_name_:
#endif
.text
/*
* void _CPU_Context_switch( run_context, heir_context )
* void _CPU_Context_restore( run_context, heir_context )
*
* This routine performs a normal non-FP context.
*
* R0 = run_context R1 = heir_context
*
* This function copies the current registers to where r0 points, then
* restores the ones from where r1 points.
*
* Using the ldm/stm opcodes save 2-3 us on 100 MHz ARM9TDMI with
* a 16 bit data bus.
*
*/
FUNC_START_ARM(_CPU_Context_switch)
/* Start saving context */
mrs r2, cpsr
stmia r0, {r2, r4, r5, r6, r7, r8, r9, r10, r11, r13, r14}
/* Start restoring context */
_restore:
ldmia r1, {r2, r4, r5, r6, r7, r8, r9, r10, r11, r13, r14}
msr cpsr, r2
#ifdef __thumb__
bx lr
nop
#else
mov pc, lr
#endif
/*
* void _CPU_Context_restore( new_context )
*
* This function copies the restores the registers from where r0 points.
* It must match _CPU_Context_switch()
*
*/
FUNC_START_ARM(_CPU_Context_restore)
mov r1, r0
b _restore
/* FIXME: _Exception_Handler_Undef_Swi is untested */
FUNC_START_ARM(_Exception_Handler_Undef_Swi)
/* FIXME: This should use load and store multiple instructions */
sub r13,r13,#SIZE_REGS
str r4, [r13, #REG_R4]
str r5, [r13, #REG_R5]
str r6, [r13, #REG_R6]
str r7, [r13, #REG_R7]
str r8, [r13, #REG_R8]
str r9, [r13, #REG_R9]
str r10, [r13, #REG_R10]
str r11, [r13, #REG_R11]
str sp, [r13, #REG_SP]
str lr, [r13, #REG_LR]
mrs r0, cpsr /* read the status */
and r0, r0,#0x1f /* we keep the mode as exception number */
str r0, [r13, #REG_PC] /* we store it in a free place */
mov r0, r13 /* put frame address in r0 (C arg 1) */
ldr r1, =SWI_Handler
ldr lr, =_go_back_1
ldr pc,[r1] /* call handler */
_go_back_1:
ldr r4, [r13, #REG_R4]
ldr r5, [r13, #REG_R5]
ldr r6, [r13, #REG_R6]
ldr r7, [r13, #REG_R7]
ldr r8, [r13, #REG_R8]
ldr r9, [r13, #REG_R9]
ldr r10, [r13, #REG_R10]
ldr r11, [r13, #REG_R11]
ldr sp, [r13, #REG_SP]
ldr lr, [r13, #REG_LR]
add r13,r13,#SIZE_REGS
movs pc,r14 /* return */
/* FIXME: _Exception_Handler_Abort is untested */
FUNC_START_ARM(_Exception_Handler_Abort)
/* FIXME: This should use load and store multiple instructions */
sub r13,r13,#SIZE_REGS
str r4, [r13, #REG_R4]
str r5, [r13, #REG_R5]
str r6, [r13, #REG_R6]
str r7, [r13, #REG_R7]
str r8, [r13, #REG_R8]
str r9, [r13, #REG_R9]
str sp, [r13, #REG_R11]
str lr, [r13, #REG_SP]
str lr, [r13, #REG_LR]
mrs r0, cpsr /* read the status */
and r0, r0,#0x1f /* we keep the mode as exception number */
str r0, [r13, #REG_PC] /* we store it in a free place */
mov r0, r13 /* put frame address in ro (C arg 1) */
ldr r1, =_currentExcHandler
ldr lr, =_go_back_2
ldr pc,[r1] /* call handler */
_go_back_2:
ldr r4, [r13, #REG_R4]
ldr r5, [r13, #REG_R5]
ldr r6, [r13, #REG_R6]
ldr r7, [r13, #REG_R7]
ldr r8, [r13, #REG_R8]
ldr r9, [r13, #REG_R9]
ldr r10, [r13, #REG_R10]
ldr sp, [r13, #REG_R11]
ldr lr, [r13, #REG_SP]
ldr lr, [r13, #REG_LR]
add r13,r13,#SIZE_REGS
#ifdef __thumb__
subs r11, r14,#4
bx r11
nop
#else
subs pc,r14,#4 /* return */
#endif
#define ABORT_REGS_OFFS 32-REG_R4
#define ABORT_SIZE_REGS SIZE_REGS+ABORT_REGS_OFFS
FUNC_START_ARM(_exc_data_abort)
sub sp, sp, #ABORT_SIZE_REGS /* reserve register frame */
stmia sp, {r0-r11}
add sp, sp, #ABORT_REGS_OFFS /* the Context_Control structure starts by CPSR, R4, ... */
str ip, [sp, #REG_PC] /* store R12 (ip) somewhere, oh hackery, hackery, hack */
str lr, [sp, #REG_LR]
mov r1, lr
ldr r0, [r1, #-8] /* r0 = bad instruction */
mrs r1, spsr /* r1 = spsr */
mov r2, r13 /* r2 = exception frame of Context_Control type */
#if defined(__thumb__)
.code 32
/*arm to thumb*/
adr r5, to_thumb + 1
bx r5
.code 16
to_thumb:
#endif
bl do_data_abort
#if defined(__thumb__)
/*back to arm*/
.code 16
thumb_to_arm:
.align 2
adr r5, arm_code
bx r5
nop
.code 32
arm_code:
#endif
ldr lr, [sp, #REG_LR]
ldr ip, [sp, #REG_PC] /* restore R12 (ip) */
sub sp, sp, #ABORT_REGS_OFFS
ldmia sp, {r0-r11}
add sp, sp, #ABORT_SIZE_REGS
#ifdef __thumb__
subs r11, r14, #4 /* return to the instruction */
bx r11
nop
#else
subs pc, r14, #4
#endif
/* _AFTER_ the aborted one */
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