ARM9 exception vectors

handlers.s

@ Copyright (C) 2015 The PASTA Team
@
@ This program is free software; you can redistribute it and/or
@ modify it under the terms of the GNU General Public License
@ version 2 as published by the Free Software Foundation
@
@ This program 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, write to the Free Software
@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

@ Slightly modified by TuxSH

.macro GEN_HANDLER name, type
	.global	\name
	.type	\name, %function

\name:
@	subs pc, lr, #4 <= this works as intended
	str	lr, [sp, #-8]

	bl	storeRegs

	ldr	r1, =\type
	b	mainHandler

	.size	\name, . - \name
.endm

	.text
	.align	2

	GEN_HANDLER handleFiq, 7
	GEN_HANDLER handleUndefinedInstr, 1
	GEN_HANDLER handleDataAbort, 4
	GEN_HANDLER handlePrefetchAbort, 3

storeRegs:	@ Except PC
	sub	sp, sp, #16
	push	{ r0-r12 }

	mrs	r0, cpsr
	mov	r1, sp

	mrs	r2, spsr
	str	r2, [sp, #64]

	tst	r2, #0xF
	orreq	r2, r2, #0xF
	bic	r2, r2, #0x10
	msr	cpsr_c, r2
	str	lr, [r1, #52]
	str	sp, [r1, #56]
	msr	cpsr_c, r0

	mov	r0, sp

	movs pc, r3
	bx	lr

main.c

#include "types.h"
#include "i2c.h"

#define REG_NUM 17

#define STACK_DUMP_SIZE 0x10000

void __attribute__((noreturn)) mainHandler(u32 regs[REG_NUM], int type)
{
	/*
	static const char regNames[REG_NUM][4] = {
		"R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7",
		"R8", "R9", "R10", "R11", "R12", "SP", "LR", "PC", "CPSR"
	};*/
	//Testing:
	i2cWriteRegister(I2C_DEV_MCU, 0x20, 1 << 0); // Shutdown	
    for(;;);

	vu32* dump = (vu32 *)0x1FF80000; // AXIWRAM
	//bool thumb = 
	
	dump[0] = 0xDEADC0DE;
	dump[1] = 0xDEADCAFE;
	dump[2] = (1 << 16) | 0; // dump format version number
	dump[3] = 9; // processor
	dump[4] = 4*REG_NUM;
	dump[5] = STACK_DUMP_SIZE;
	dump[6] = 0;
	dump[7] = (u32)type;
	
	// Dump registers
	vu32* regdump = dump + 8;
	for(int i = 0; i < REG_NUM; ++i)
		regdump[i] = regs[i];
		
	// Dump stack
	vu32* sp = (vu32*) regs[13];
	vu32* stackdump = regdump + REG_NUM;
	for(int i = 0; i < STACK_DUMP_SIZE/4; ++i)
		stackdump[i] = sp[i];
	
	//vu32* codedump = stackdump + STACK_DUMP_SIZE/4;

	i2cWriteRegister(I2C_DEV_MCU, 0x20, 1 << 0); // Shutdown	
	//i2cWriteRegister(I2C_DEV_MCU, 0x20, 1 << 2); // Reboot
    for(;;);
}

// Implemented in handlers.s:
void handleFiq(void);
void handleUndefinedInstr(void);
void handleDataAbort(void);
void handlePrefetchAbort(void);

void main(void)
{
	for(vu32* vecs = (vu32 *)0x08000008; vecs < (vu32 *)0x08000030; vecs += 2)
	{
		vecs[0] = 0xE51FF004; // ldr pc, [pc, -4]
		vecs[1] = (u32)&handleDataAbort;
	}
}