ARMv5-instruction-set-emulator/arm_exception.c at main · CocoElAbricot/ARMv5-instruction-set-emulator · GitHub

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/*
Armator - simulateur de jeu d'instruction ARMv5T   but p dagogique
Copyright (C) 2011 Guillaume Huard
Ce programme est libre, vous pouvez le redistribuer et/ou le modifier selon les
termes de la Licence Publique G n rale GNU publi e par la Free Software
Foundation (version 2 ou bien toute autre version ult rieure choisie par vous).

Ce programme est distribu  car potentiellement utile, mais SANS AUCUNE
GARANTIE, ni explicite ni implicite, y compris les garanties de
commercialisation ou d'adaptation dans un but sp cifique. Reportez-vous   la
Licence Publique G n rale GNU pour plus de d tails.

Vous devez avoir re u une copie de la Licence Publique G n rale GNU en m me
temps que ce programme ; si ce n'est pas le cas,  crivez   la Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307,
 tats-Unis.

Contact: Guillaume.Huard@imag.fr
	 B timent IMAG
	 700 avenue centrale, domaine universitaire
	 38401 Saint Martin d'H res
*/
#include "arm_exception.h"
#include "arm_constants.h"
#include "arm_core.h"
#include "util.h"

// Not supported below ARMv6, should read as 0
#define CP15_reg1_EEbit 0
#define Exception_bit_9 (CP15_reg1_EEbit << 9)

int arm_exception(arm_core p, uint8_t exception) {
    uint32_t cpsr = 0x1d3 | Exception_bit_9;
    /* As there is no operating system in our simulator, we handle
     * software interrupts here :
     * - 0x123456 is the end of the simulation
     * - other opcodes can be used for any custom behavior,
     *   such as my_putchar given as an example
     */
    switch (exception) {
        case SOFTWARE_INTERRUPT:
            uint32_t value;
            uint32_t address = arm_read_register(p, 15);
            address -= 8;
            uint32_t instruction;
            arm_read_word(p, address, &instruction);
            instruction &= 0xFFFFFF;
            switch (instruction) {
                case 0x123456:
                    return END_SIMULATION;
                case 0x000001:
                    value = arm_read_register(p, 0);
                    putchar(value);
                    return 0;
            }
            break;
        case RESET:
            arm_write_cpsr(p, cpsr);
            arm_write_register(p, 15, 0);
            break;
        case UNDEFINED_INSTRUCTION:
            cpsr = cpsr | (1 << 3);
            arm_write_cpsr(p, cpsr);
            arm_write_register(p, 15, 4);
            break;
        case PREFETCH_ABORT:
            cpsr = cpsr | (1 << 2);
            arm_write_cpsr(p, cpsr);
            arm_write_register(p, 15, 12);
            break;
        case DATA_ABORT:
            cpsr = cpsr | (1 << 2);
            arm_write_cpsr(p, cpsr);
            arm_write_register(p, 15, 16);
            break;
        case INTERRUPT:
            cpsr = cpsr & ~(1 << 0);
            arm_write_cpsr(p, cpsr);
            arm_write_register(p, 15, 24);
            break;
        case FAST_INTERRUPT:
            cpsr = cpsr & ~(1 << 1);
            arm_write_cpsr(p, cpsr);
            arm_write_register(p, 15, 26);
            break;
        default:
            return arm_exception(p, UNDEFINED_INSTRUCTION);
    }
    printf("Exception : %x \n", exception);
    return exception;
}