core: Ensure we can run in >64K flash

[simavr] / simavr / sim / sim_avr.h

/*
        sim_avr.h

        Copyright 2008-2012 Michel Pollet <buserror@gmail.com>

        This file is part of simavr.

        simavr is free software: you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation, either version 3 of the License, or
        (at your option) any later version.

        simavr 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 simavr.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef __SIM_AVR_H__
#define __SIM_AVR_H__

#ifdef __cplusplus
extern "C" {
#endif

#include "sim_irq.h"
#include "sim_interrupts.h"
#include "sim_cycle_timers.h"

typedef uint32_t avr_flashaddr_t;

struct avr_t;
typedef uint8_t (*avr_io_read_t)(
                struct avr_t * avr,
                avr_io_addr_t addr,
                void * param);
typedef void (*avr_io_write_t)(
                struct avr_t * avr,
                avr_io_addr_t addr,
                uint8_t v,
                void * param);

enum {
        // SREG bit indexes
        S_C = 0,S_Z,S_N,S_V,S_S,S_H,S_T,S_I,

        // 16 bits register pairs
        R_XL    = 0x1a, R_XH,R_YL,R_YH,R_ZL,R_ZH,
        // stack pointer
        R_SPL   = 32+0x3d, R_SPH,
        // real SREG
        R_SREG  = 32+0x3f,

        // maximum number of IO registers, on normal AVRs
        MAX_IOs = 256,  // Bigger AVRs need more than 256-32 (mega1280)
};

#define AVR_DATA_TO_IO(v) ((v) - 32)
#define AVR_IO_TO_DATA(v) ((v) + 32)

/*
 * Core states.
 */
enum {
        cpu_Limbo = 0,  // before initialization is finished
        cpu_Stopped,    // all is stopped, timers included

        cpu_Running,    // we're free running

        cpu_Sleeping,   // we're now sleeping until an interrupt

        cpu_Step,               // run ONE instruction, then...
        cpu_StepDone,   // tell gdb it's all OK, and give it registers
        cpu_Done,       // avr software stopped gracefully
        cpu_Crashed,    // avr software crashed (watchdog fired)
};

// this is only ever used if CONFIG_SIMAVR_TRACE is defined
struct avr_trace_data_t {
        struct avr_symbol_t ** codeline;

        /* DEBUG ONLY
         * this keeps track of "jumps" ie, call,jmp,ret,reti and so on
         * allows dumping of a meaningful data even if the stack is
         * munched and so on
         */
        #define OLD_PC_SIZE     32
        struct {
                uint32_t pc;
                uint16_t sp;
        } old[OLD_PC_SIZE]; // catches reset..
        int                     old_pci;

#if AVR_STACK_WATCH
        #define STACK_FRAME_SIZE        32
        // this records the call/ret pairs, to try to catch
        // code that munches the stack -under- their own frame
        struct {
                uint32_t        pc;
                uint16_t        sp;             
        } stack_frame[STACK_FRAME_SIZE];
        int                     stack_frame_index;
#endif

        // DEBUG ONLY
        // keeps track of which registers gets touched by instructions
        // reset before each new instructions. Allows meaningful traces
        uint32_t        touched[256 / 32];      // debug
};

/*
 * Main AVR instance. Some of these fields are set by the AVR "Core" definition files
 * the rest is runtime data (as little as possible)
 */
typedef struct avr_t {
        const char * mmcu;      // name of the AVR
        // these are filled by sim_core_declare from constants in /usr/lib/avr/include/avr/io*.h
        uint16_t        ramend;         
        uint32_t        flashend;
        uint32_t        e2end;
        uint8_t         vector_size;
        uint8_t         signature[3];
        uint8_t         fuse[4];
        avr_io_addr_t   rampz;  // optional, only for ELPM/SPM on >64Kb cores
        avr_io_addr_t   eind;   // optional, only for EIJMP/EICALL on >64Kb cores

        // filled by the ELF data, this allow tracking of invalid jumps
        uint32_t                        codeend;

        int                                     state;          // stopped, running, sleeping
        uint32_t                        frequency;      // frequency we are running at
        // mostly used by the ADC for now
        uint32_t                        vcc,avcc,aref; // (optional) voltages in millivolts

        // cycles gets incremented when sleeping and when running; it corresponds
        // not only to "cycles that runs" but also "cycles that might have run"
        // like, sleeping.
        avr_cycle_count_t       cycle;          // current cycle
        
        // called at init time
        void (*init)(struct avr_t * avr);
        // called at init time (for special purposes like using a memory mapped file as flash see: simduino)
        void (*special_init)(struct avr_t * avr);
        // called at termination time ( to clean special initalizations)
        void (*special_deinit)(struct avr_t * avr);
        // called at reset time
        void (*reset)(struct avr_t * avr);

        /*!
         * Default AVR core run function.
         * Two modes are available, a "raw" run that goes as fast as
         * it can, and a "gdb" mode that also watchouts for gdb events
         * and is a little bit slower.
         */
        void (*run)(struct avr_t * avr);

        /*!
         * Sleep default behaviour.
         * In "raw" mode, it calls usleep, in gdb mode, it waits
         * for howLong for gdb command on it's sockets.
         */
        void (*sleep)(struct avr_t * avr, avr_cycle_count_t howLong);

        /*!
         * Every IRQs will be stored in this pool. It is not
         * mandatory (yet) but will allow listing IRQs and their connections
         */
        avr_irq_pool_t  irq_pool;

        // Mirror of the SREG register, to facilitate the access to bits
        // in the opcode decoder.
        // This array is re-synthetized back/forth when SREG changes
        uint8_t         sreg[8];
        uint8_t         i_shadow;       // used to detect edges on I flag

        /* 
         * ** current PC **
         * Note that the PC is representing /bytes/ while the AVR value is
         * assumed to be "words". This is in line with what GDB does...
         * this is why you will see >>1 and <<1 in the decoder to handle jumps.
         * It CAN be a little confusing, so concentrate, young grasshopper.
         */
        avr_flashaddr_t pc;

        /*
         * callback when specific IO registers are read/written.
         * There is one drawback here, there is in way of knowing what is the
         * "beginning of useful sram" on a core, so there is no way to deduce
         * what is the maximum IO register for a core, and thus, we can't
         * allocate this table dynamically.
         * If you wanted to emulate the BIG AVRs, and XMegas, this would need
         * work.
         */
        struct {
                struct avr_irq_t * irq; // optional, used only if asked for with avr_iomem_getirq()
                struct {
                        void * param;
                        avr_io_read_t c;
                } r;
                struct {
                        void * param;
                        avr_io_write_t c;
                } w;
        } io[MAX_IOs];

        /*
         * This block allows sharing of the IO write/read on addresses between
         * multiple callbacks. In 99% of case it's not needed, however on the tiny*
         * (tiny85 at last) some registers have bits that are used by different
         * IO modules.
         * If this case is detected, a special "dispatch" callback is installed that
         * will handle this particular case, without impacting the performance of the
         * other, normal cases...
         */
        int     io_shared_io_count;
        struct {
                int used;
                struct {
                        void * param;
                        void * c;
                } io[4];
        } io_shared_io[4];

        // flash memory (initialized to 0xff, and code loaded into it)
        uint8_t *       flash;
        // this is the general purpose registers, IO registers, and SRAM
        uint8_t *       data;

        // queue of io modules
        struct avr_io_t *io_port;

        // cycle timers tracking & delivery
        avr_cycle_timer_pool_t  cycle_timers;
        // interrupt vectors and delivery fifo
        avr_int_table_t interrupts;

        // DEBUG ONLY -- value ignored if CONFIG_SIMAVR_TRACE = 0
        int             trace : 1,
                        log : 2; // log level, default to 1

        // Only used if CONFIG_SIMAVR_TRACE is defined
        struct avr_trace_data_t *trace_data;

        // VALUE CHANGE DUMP file (waveforms)
        // this is the VCD file that gets allocated if the 
        // firmware that is loaded explicitly asks for a trace
        // to be generated, and allocates it's own symbols
        // using AVR_MMCU_TAG_VCD_TRACE (see avr_mcu_section.h)
        struct avr_vcd_t * vcd;
        
        // gdb hooking structure. Only present when gdb server is active
        struct avr_gdb_t * gdb;

        // if non-zero, the gdb server will be started when the core
        // crashed even if not activated at startup
        // if zero, the simulator will just exit() in case of a crash
        int             gdb_port;
} avr_t;


// this is a static constructor for each of the AVR devices
typedef struct avr_kind_t {
        const char * names[4];  // name aliases
        avr_t * (*make)();
} avr_kind_t;

// a symbol loaded from the .elf file
typedef struct avr_symbol_t {
        const char * symbol;
        uint32_t        addr;
} avr_symbol_t;

// locate the maker for mcu "name" and allocates a new avr instance
avr_t *
avr_make_mcu_by_name(
                const char *name);
// initializes a new AVR instance. Will call the IO registers init(), and then reset()
int
avr_init(
                avr_t * avr);
// resets the AVR, and the IO modules
void
avr_reset(
                avr_t * avr);
// run one cycle of the AVR, sleep if necessary
int
avr_run(
                avr_t * avr);
// finish any pending operations 
void
avr_terminate(
                avr_t * avr);

// set an IO register to receive commands from the AVR firmware
// it's optional, and uses the ELF tags
void
avr_set_command_register(
                avr_t * avr,
                avr_io_addr_t addr);

// specify the "console register" -- output sent to this register
// is printed on the simulator console, without using a UART
void
avr_set_console_register(
                avr_t * avr,
                avr_io_addr_t addr);

// load code in the "flash"
void
avr_loadcode(
                avr_t * avr,
                uint8_t * code,
                uint32_t size,
                avr_flashaddr_t address);

/*
 * these are accessors for avr->data but allows watchpoints to be set for gdb
 * IO modules use that to set values to registers, and the AVR core decoder uses
 * that to register "public" read by instructions.
 */
void
avr_core_watch_write(
                avr_t *avr,
                uint16_t addr,
                uint8_t v);
uint8_t
avr_core_watch_read(
                avr_t *avr,
                uint16_t addr);

// called when the core has detected a crash somehow.
// this might activate gdb server
void
avr_sadly_crashed(
                avr_t *avr,
                uint8_t signal);


/*
 * These are callbacks for the two 'main' bahaviour in simavr
 */
void avr_callback_sleep_gdb(avr_t * avr, avr_cycle_count_t howLong);
void avr_callback_run_gdb(avr_t * avr);
void avr_callback_sleep_raw(avr_t * avr, avr_cycle_count_t howLong);
void avr_callback_run_raw(avr_t * avr);

#ifdef __cplusplus
};
#endif

#include "sim_io.h"
#include "sim_regbit.h"

#endif /*__SIM_AVR_H__*/