target/avr/helper.c

   1 /*
   2  * QEMU AVR CPU helpers
   3  *
   4  * Copyright (c) 2016-2020 Michael Rolnik
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see
  18  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "cpu.h"
  23 #include "exec/exec-all.h"
  24 #include "exec/helper-proto.h"
  25
  26 bool avr_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
  27 {
  28     bool ret = false;
  29     CPUClass *cc = CPU_GET_CLASS(cs);
  30     AVRCPU *cpu = AVR_CPU(cs);
  31     CPUAVRState *env = &cpu->env;
  32
  33     if (interrupt_request & CPU_INTERRUPT_RESET) {
  34         if (cpu_interrupts_enabled(env)) {
  35             cs->exception_index = EXCP_RESET;
  36             cc->do_interrupt(cs);
  37
  38             cs->interrupt_request &= ~CPU_INTERRUPT_RESET;
  39
  40             ret = true;
  41         }
  42     }
  43     if (interrupt_request & CPU_INTERRUPT_HARD) {
  44         if (cpu_interrupts_enabled(env) && env->intsrc != 0) {
  45             int index = ctz32(env->intsrc);
  46             cs->exception_index = EXCP_INT(index);
  47             cc->do_interrupt(cs);
  48
  49             env->intsrc &= env->intsrc - 1; /* clear the interrupt */
  50             cs->interrupt_request &= ~CPU_INTERRUPT_HARD;
  51
  52             ret = true;
  53         }
  54     }
  55     return ret;
  56 }
  57
  58 void avr_cpu_do_interrupt(CPUState *cs)
  59 {
  60     AVRCPU *cpu = AVR_CPU(cs);
  61     CPUAVRState *env = &cpu->env;
  62
  63     uint32_t ret = env->pc_w;
  64     int vector = 0;
  65     int size = avr_feature(env, AVR_FEATURE_JMP_CALL) ? 2 : 1;
  66     int base = 0;
  67
  68     if (cs->exception_index == EXCP_RESET) {
  69         vector = 0;
  70     } else if (env->intsrc != 0) {
  71         vector = ctz32(env->intsrc) + 1;
  72     }
  73
  74     if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {
  75         cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
  76         cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
  77         cpu_stb_data(env, env->sp--, (ret & 0xff0000) >> 16);
  78     } else if (avr_feature(env, AVR_FEATURE_2_BYTE_PC)) {
  79         cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
  80         cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
  81     } else {
  82         cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
  83     }
  84
  85     env->pc_w = base + vector * size;
  86     env->sregI = 0; /* clear Global Interrupt Flag */
  87
  88     cs->exception_index = -1;
  89 }