target/avr/helper.c - qemu - Git at Google

 /*
  * QEMU AVR CPU helpers
  *
  * Copyright (c) 2016-2020 Michael Rolnik
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see
  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  */

 #include "qemu/osdep.h"
 #include "qemu/log.h"
 #include "qemu/error-report.h"
 #include "cpu.h"
 #include "hw/core/tcg-cpu-ops.h"
 #include "exec/exec-all.h"
 #include "exec/page-protection.h"
 #include "exec/cpu_ldst.h"
 #include "exec/address-spaces.h"
 #include "exec/helper-proto.h"

 bool avr_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
 {
     CPUAVRState *env = cpu_env(cs);

     /*
      * We cannot separate a skip from the next instruction,
      * as the skip would not be preserved across the interrupt.
      * Separating the two insn normally only happens at page boundaries.
      */
     if (env->skip) {
         return false;
     }

     if (interrupt_request & CPU_INTERRUPT_RESET) {
         if (cpu_interrupts_enabled(env)) {
             cs->exception_index = EXCP_RESET;
             avr_cpu_do_interrupt(cs);

             cs->interrupt_request &= ~CPU_INTERRUPT_RESET;
             return true;
         }
     }
     if (interrupt_request & CPU_INTERRUPT_HARD) {
         if (cpu_interrupts_enabled(env) && env->intsrc != 0) {
             int index = ctz64(env->intsrc);
             cs->exception_index = EXCP_INT(index);
             avr_cpu_do_interrupt(cs);

             env->intsrc &= env->intsrc - 1; /* clear the interrupt */
             if (!env->intsrc) {
                 cs->interrupt_request &= ~CPU_INTERRUPT_HARD;
             }
             return true;
         }
     }
     return false;
 }

 void avr_cpu_do_interrupt(CPUState *cs)
 {
     CPUAVRState *env = cpu_env(cs);

     uint32_t ret = env->pc_w;
     int vector = 0;
     int size = avr_feature(env, AVR_FEATURE_JMP_CALL) ? 2 : 1;
     int base = 0;

     if (cs->exception_index == EXCP_RESET) {
         vector = 0;
     } else if (env->intsrc != 0) {
         vector = ctz64(env->intsrc) + 1;
     }

     if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {
         cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
         cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
         cpu_stb_data(env, env->sp--, (ret & 0xff0000) >> 16);
     } else if (avr_feature(env, AVR_FEATURE_2_BYTE_PC)) {
         cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
         cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
     } else {
         cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
     }

     env->pc_w = base + vector * size;
     env->sregI = 0; /* clear Global Interrupt Flag */

     cs->exception_index = -1;
 }

 hwaddr avr_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
 {
     return addr; /* I assume 1:1 address correspondence */
 }

 bool avr_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                       MMUAccessType access_type, int mmu_idx,
                       bool probe, uintptr_t retaddr)
 {
     int prot, page_size = TARGET_PAGE_SIZE;
     uint32_t paddr;

     address &= TARGET_PAGE_MASK;

     if (mmu_idx == MMU_CODE_IDX) {
         /* Access to code in flash. */
         paddr = OFFSET_CODE + address;
         prot = PAGE_READ | PAGE_EXEC;
         if (paddr >= OFFSET_DATA) {
             /*
              * This should not be possible via any architectural operations.
              * There is certainly not an exception that we can deliver.
              * Accept probing that might come from generic code.
              */
             if (probe) {
                 return false;
             }
             error_report("execution left flash memory");
             abort();
         }
     } else {
         /* Access to memory. */
         paddr = OFFSET_DATA + address;
         prot = PAGE_READ | PAGE_WRITE;
         if (address < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
             /*
              * Access to CPU registers, exit and rebuilt this TB to use
              * full access in case it touches specially handled registers
              * like SREG or SP.  For probing, set page_size = 1, in order
              * to force tlb_fill to be called for the next access.
              */
             if (probe) {
                 page_size = 1;
             } else {
                 cpu_env(cs)->fullacc = 1;
                 cpu_loop_exit_restore(cs, retaddr);
             }
         }
     }

     tlb_set_page(cs, address, paddr, prot, mmu_idx, page_size);
     return true;
 }

 /*
  *  helpers
  */

 void helper_sleep(CPUAVRState *env)
 {
     CPUState *cs = env_cpu(env);

     cs->exception_index = EXCP_HLT;
     cpu_loop_exit(cs);
 }

 void helper_unsupported(CPUAVRState *env)
 {
     CPUState *cs = env_cpu(env);

     /*
      *  I count not find what happens on the real platform, so
      *  it's EXCP_DEBUG for meanwhile
      */
     cs->exception_index = EXCP_DEBUG;
     if (qemu_loglevel_mask(LOG_UNIMP)) {
         qemu_log("UNSUPPORTED\n");
         cpu_dump_state(cs, stderr, 0);
     }
     cpu_loop_exit(cs);
 }

 void helper_debug(CPUAVRState *env)
 {
     CPUState *cs = env_cpu(env);

     cs->exception_index = EXCP_DEBUG;
     cpu_loop_exit(cs);
 }

 void helper_break(CPUAVRState *env)
 {
     CPUState *cs = env_cpu(env);

     cs->exception_index = EXCP_DEBUG;
     cpu_loop_exit(cs);
 }

 void helper_wdr(CPUAVRState *env)
 {
     qemu_log_mask(LOG_UNIMP, "WDG reset (not implemented)\n");
 }

 /*
  * This function implements IN instruction
  *
  * It does the following
  * a.  if an IO register belongs to CPU, its value is read and returned
  * b.  otherwise io address is translated to mem address and physical memory
  *     is read.
  * c.  it caches the value for sake of SBI, SBIC, SBIS & CBI implementation
  *
  */
 target_ulong helper_inb(CPUAVRState *env, uint32_t port)
 {
     target_ulong data = 0;

     switch (port) {
     case 0x38: /* RAMPD */
         data = 0xff & (env->rampD >> 16);
         break;
     case 0x39: /* RAMPX */
         data = 0xff & (env->rampX >> 16);
         break;
     case 0x3a: /* RAMPY */
         data = 0xff & (env->rampY >> 16);
         break;
     case 0x3b: /* RAMPZ */
         data = 0xff & (env->rampZ >> 16);
         break;
     case 0x3c: /* EIND */
         data = 0xff & (env->eind >> 16);
         break;
     case 0x3d: /* SPL */
         data = env->sp & 0x00ff;
         break;
     case 0x3e: /* SPH */
         data = env->sp >> 8;
         break;
     case 0x3f: /* SREG */
         data = cpu_get_sreg(env);
         break;
     default:
         /* not a special register, pass to normal memory access */
         data = address_space_ldub(&address_space_memory,
                                   OFFSET_IO_REGISTERS + port,
                                   MEMTXATTRS_UNSPECIFIED, NULL);
     }

     return data;
 }

 /*
  *  This function implements OUT instruction
  *
  *  It does the following
  *  a.  if an IO register belongs to CPU, its value is written into the register
  *  b.  otherwise io address is translated to mem address and physical memory
  *      is written.
  *  c.  it caches the value for sake of SBI, SBIC, SBIS & CBI implementation
  *
  */
 void helper_outb(CPUAVRState *env, uint32_t port, uint32_t data)
 {
     data &= 0x000000ff;

     switch (port) {
     case 0x38: /* RAMPD */
         if (avr_feature(env, AVR_FEATURE_RAMPD)) {
             env->rampD = (data & 0xff) << 16;
         }
         break;
     case 0x39: /* RAMPX */
         if (avr_feature(env, AVR_FEATURE_RAMPX)) {
             env->rampX = (data & 0xff) << 16;
         }
         break;
     case 0x3a: /* RAMPY */
         if (avr_feature(env, AVR_FEATURE_RAMPY)) {
             env->rampY = (data & 0xff) << 16;
         }
         break;
     case 0x3b: /* RAMPZ */
         if (avr_feature(env, AVR_FEATURE_RAMPZ)) {
             env->rampZ = (data & 0xff) << 16;
         }
         break;
     case 0x3c: /* EIDN */
         env->eind = (data & 0xff) << 16;
         break;
     case 0x3d: /* SPL */
         env->sp = (env->sp & 0xff00) | (data);
         break;
     case 0x3e: /* SPH */
         if (avr_feature(env, AVR_FEATURE_2_BYTE_SP)) {
             env->sp = (env->sp & 0x00ff) | (data << 8);
         }
         break;
     case 0x3f: /* SREG */
         cpu_set_sreg(env, data);
         break;
     default:
         /* not a special register, pass to normal memory access */
         address_space_stb(&address_space_memory, OFFSET_IO_REGISTERS + port,
                           data, MEMTXATTRS_UNSPECIFIED, NULL);
     }
 }

 /*
  *  this function implements LD instruction when there is a possibility to read
  *  from a CPU register
  */
 target_ulong helper_fullrd(CPUAVRState *env, uint32_t addr)
 {
     uint8_t data;

     env->fullacc = false;

     if (addr < NUMBER_OF_CPU_REGISTERS) {
         /* CPU registers */
         data = env->r[addr];
     } else if (addr < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
         /* IO registers */
         data = helper_inb(env, addr - NUMBER_OF_CPU_REGISTERS);
     } else {
         /* memory */
         data = address_space_ldub(&address_space_memory, OFFSET_DATA + addr,
                                   MEMTXATTRS_UNSPECIFIED, NULL);
     }
     return data;
 }

 /*
  *  this function implements ST instruction when there is a possibility to write
  *  into a CPU register
  */
 void helper_fullwr(CPUAVRState *env, uint32_t data, uint32_t addr)
 {
     env->fullacc = false;

     /* Following logic assumes this: */
     assert(OFFSET_CPU_REGISTERS == OFFSET_DATA);
     assert(OFFSET_IO_REGISTERS == OFFSET_CPU_REGISTERS +
                                   NUMBER_OF_CPU_REGISTERS);

     if (addr < NUMBER_OF_CPU_REGISTERS) {
         /* CPU registers */
         env->r[addr] = data;
     } else if (addr < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
         /* IO registers */
         helper_outb(env, addr - NUMBER_OF_CPU_REGISTERS, data);
     } else {
         /* memory */
         address_space_stb(&address_space_memory, OFFSET_DATA + addr, data,
                           MEMTXATTRS_UNSPECIFIED, NULL);
     }
 }
	/*
	* QEMU AVR CPU helpers
	*
	* Copyright (c) 2016-2020 Michael Rolnik
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library 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
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, see
	* <http://www.gnu.org/licenses/lgpl-2.1.html>
	*/

	#include "qemu/osdep.h"
	#include "qemu/log.h"
	#include "qemu/error-report.h"
	#include "cpu.h"
	#include "hw/core/tcg-cpu-ops.h"
	#include "exec/exec-all.h"
	#include "exec/page-protection.h"
	#include "exec/cpu_ldst.h"
	#include "exec/address-spaces.h"
	#include "exec/helper-proto.h"

	bool avr_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
	{
	CPUAVRState *env = cpu_env(cs);

	/*
	* We cannot separate a skip from the next instruction,
	* as the skip would not be preserved across the interrupt.
	* Separating the two insn normally only happens at page boundaries.
	*/
	if (env->skip) {
	return false;
	}

	if (interrupt_request & CPU_INTERRUPT_RESET) {
	if (cpu_interrupts_enabled(env)) {
	cs->exception_index = EXCP_RESET;
	avr_cpu_do_interrupt(cs);

	cs->interrupt_request &= ~CPU_INTERRUPT_RESET;
	return true;
	}
	}
	if (interrupt_request & CPU_INTERRUPT_HARD) {
	if (cpu_interrupts_enabled(env) && env->intsrc != 0) {
	int index = ctz64(env->intsrc);
	cs->exception_index = EXCP_INT(index);
	avr_cpu_do_interrupt(cs);

	env->intsrc &= env->intsrc - 1; /* clear the interrupt */
	if (!env->intsrc) {
	cs->interrupt_request &= ~CPU_INTERRUPT_HARD;
	}
	return true;
	}
	}
	return false;
	}

	void avr_cpu_do_interrupt(CPUState *cs)
	{
	CPUAVRState *env = cpu_env(cs);

	uint32_t ret = env->pc_w;
	int vector = 0;
	int size = avr_feature(env, AVR_FEATURE_JMP_CALL) ? 2 : 1;
	int base = 0;

	if (cs->exception_index == EXCP_RESET) {
	vector = 0;
	} else if (env->intsrc != 0) {
	vector = ctz64(env->intsrc) + 1;
	}

	if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {
	cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
	cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
	cpu_stb_data(env, env->sp--, (ret & 0xff0000) >> 16);
	} else if (avr_feature(env, AVR_FEATURE_2_BYTE_PC)) {
	cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
	cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
	} else {
	cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
	}

	env->pc_w = base + vector * size;
	env->sregI = 0; /* clear Global Interrupt Flag */

	cs->exception_index = -1;
	}

	hwaddr avr_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
	{
	return addr; /* I assume 1:1 address correspondence */
	}

	bool avr_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
	MMUAccessType access_type, int mmu_idx,
	bool probe, uintptr_t retaddr)
	{
	int prot, page_size = TARGET_PAGE_SIZE;
	uint32_t paddr;

	address &= TARGET_PAGE_MASK;

	if (mmu_idx == MMU_CODE_IDX) {
	/* Access to code in flash. */
	paddr = OFFSET_CODE + address;
	prot = PAGE_READ \| PAGE_EXEC;
	if (paddr >= OFFSET_DATA) {
	/*
	* This should not be possible via any architectural operations.
	* There is certainly not an exception that we can deliver.
	* Accept probing that might come from generic code.
	*/
	if (probe) {
	return false;
	}
	error_report("execution left flash memory");
	abort();
	}
	} else {
	/* Access to memory. */
	paddr = OFFSET_DATA + address;
	prot = PAGE_READ \| PAGE_WRITE;
	if (address < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
	/*
	* Access to CPU registers, exit and rebuilt this TB to use
	* full access in case it touches specially handled registers
	* like SREG or SP. For probing, set page_size = 1, in order
	* to force tlb_fill to be called for the next access.
	*/
	if (probe) {
	page_size = 1;
	} else {
	cpu_env(cs)->fullacc = 1;
	cpu_loop_exit_restore(cs, retaddr);
	}
	}
	}

	tlb_set_page(cs, address, paddr, prot, mmu_idx, page_size);
	return true;
	}

	/*
	* helpers
	*/

	void helper_sleep(CPUAVRState *env)
	{
	CPUState *cs = env_cpu(env);

	cs->exception_index = EXCP_HLT;
	cpu_loop_exit(cs);
	}

	void helper_unsupported(CPUAVRState *env)
	{
	CPUState *cs = env_cpu(env);

	/*
	* I count not find what happens on the real platform, so
	* it's EXCP_DEBUG for meanwhile
	*/
	cs->exception_index = EXCP_DEBUG;
	if (qemu_loglevel_mask(LOG_UNIMP)) {
	qemu_log("UNSUPPORTED\n");
	cpu_dump_state(cs, stderr, 0);
	}
	cpu_loop_exit(cs);
	}

	void helper_debug(CPUAVRState *env)
	{
	CPUState *cs = env_cpu(env);

	cs->exception_index = EXCP_DEBUG;
	cpu_loop_exit(cs);
	}

	void helper_break(CPUAVRState *env)
	{
	CPUState *cs = env_cpu(env);

	cs->exception_index = EXCP_DEBUG;
	cpu_loop_exit(cs);
	}

	void helper_wdr(CPUAVRState *env)
	{
	qemu_log_mask(LOG_UNIMP, "WDG reset (not implemented)\n");
	}

	/*
	* This function implements IN instruction
	*
	* It does the following
	* a. if an IO register belongs to CPU, its value is read and returned
	* b. otherwise io address is translated to mem address and physical memory
	* is read.
	* c. it caches the value for sake of SBI, SBIC, SBIS & CBI implementation
	*
	*/
	target_ulong helper_inb(CPUAVRState *env, uint32_t port)
	{
	target_ulong data = 0;

	switch (port) {
	case 0x38: /* RAMPD */
	data = 0xff & (env->rampD >> 16);
	break;
	case 0x39: /* RAMPX */
	data = 0xff & (env->rampX >> 16);
	break;
	case 0x3a: /* RAMPY */
	data = 0xff & (env->rampY >> 16);
	break;
	case 0x3b: /* RAMPZ */
	data = 0xff & (env->rampZ >> 16);
	break;
	case 0x3c: /* EIND */
	data = 0xff & (env->eind >> 16);
	break;
	case 0x3d: /* SPL */
	data = env->sp & 0x00ff;
	break;
	case 0x3e: /* SPH */
	data = env->sp >> 8;
	break;
	case 0x3f: /* SREG */
	data = cpu_get_sreg(env);
	break;
	default:
	/* not a special register, pass to normal memory access */
	data = address_space_ldub(&address_space_memory,
	OFFSET_IO_REGISTERS + port,
	MEMTXATTRS_UNSPECIFIED, NULL);
	}

	return data;
	}

	/*
	* This function implements OUT instruction
	*
	* It does the following
	* a. if an IO register belongs to CPU, its value is written into the register
	* b. otherwise io address is translated to mem address and physical memory
	* is written.
	* c. it caches the value for sake of SBI, SBIC, SBIS & CBI implementation
	*
	*/
	void helper_outb(CPUAVRState *env, uint32_t port, uint32_t data)
	{
	data &= 0x000000ff;

	switch (port) {
	case 0x38: /* RAMPD */
	if (avr_feature(env, AVR_FEATURE_RAMPD)) {
	env->rampD = (data & 0xff) << 16;
	}
	break;
	case 0x39: /* RAMPX */
	if (avr_feature(env, AVR_FEATURE_RAMPX)) {
	env->rampX = (data & 0xff) << 16;
	}
	break;
	case 0x3a: /* RAMPY */
	if (avr_feature(env, AVR_FEATURE_RAMPY)) {
	env->rampY = (data & 0xff) << 16;
	}
	break;
	case 0x3b: /* RAMPZ */
	if (avr_feature(env, AVR_FEATURE_RAMPZ)) {
	env->rampZ = (data & 0xff) << 16;
	}
	break;
	case 0x3c: /* EIDN */
	env->eind = (data & 0xff) << 16;
	break;
	case 0x3d: /* SPL */
	env->sp = (env->sp & 0xff00) \| (data);
	break;
	case 0x3e: /* SPH */
	if (avr_feature(env, AVR_FEATURE_2_BYTE_SP)) {
	env->sp = (env->sp & 0x00ff) \| (data << 8);
	}
	break;
	case 0x3f: /* SREG */
	cpu_set_sreg(env, data);
	break;
	default:
	/* not a special register, pass to normal memory access */
	address_space_stb(&address_space_memory, OFFSET_IO_REGISTERS + port,
	data, MEMTXATTRS_UNSPECIFIED, NULL);
	}
	}

	/*
	* this function implements LD instruction when there is a possibility to read
	* from a CPU register
	*/
	target_ulong helper_fullrd(CPUAVRState *env, uint32_t addr)
	{
	uint8_t data;

	env->fullacc = false;

	if (addr < NUMBER_OF_CPU_REGISTERS) {
	/* CPU registers */
	data = env->r[addr];
	} else if (addr < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
	/* IO registers */
	data = helper_inb(env, addr - NUMBER_OF_CPU_REGISTERS);
	} else {
	/* memory */
	data = address_space_ldub(&address_space_memory, OFFSET_DATA + addr,
	MEMTXATTRS_UNSPECIFIED, NULL);
	}
	return data;
	}

	/*
	* this function implements ST instruction when there is a possibility to write
	* into a CPU register
	*/
	void helper_fullwr(CPUAVRState *env, uint32_t data, uint32_t addr)
	{
	env->fullacc = false;

	/* Following logic assumes this: */
	assert(OFFSET_CPU_REGISTERS == OFFSET_DATA);
	assert(OFFSET_IO_REGISTERS == OFFSET_CPU_REGISTERS +
	NUMBER_OF_CPU_REGISTERS);

	if (addr < NUMBER_OF_CPU_REGISTERS) {
	/* CPU registers */
	env->r[addr] = data;
	} else if (addr < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
	/* IO registers */
	helper_outb(env, addr - NUMBER_OF_CPU_REGISTERS, data);
	} else {
	/* memory */
	address_space_stb(&address_space_memory, OFFSET_DATA + addr, data,
	MEMTXATTRS_UNSPECIFIED, NULL);
	}
	}