// The OS/K Team licences this file to you under the MIT license.
// See the LICENCE file in the project root for more information.

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

#define log printf

#define packed __attribute__ ((__packed__))
#define static_assert _Static_assert

typedef unsigned int        bool;
typedef unsigned char       uchar;
typedef unsigned short      ushort;
typedef unsigned int        uint;
typedef unsigned long       ulong;

typedef struct reg_t        reg_t;
typedef struct ctx_t        ctx_t;
typedef struct instr_t      instr_t;
typedef struct acc_t        acc_t;
typedef struct arch_t       arch_t;

enum
{
    RAX, RBX, RCX, RDX, RDI, RSI, RBP, RSP,
    R08, R09, R10, R11, R12, R13, R14, R15,
    K00, K01, K02, K03, K04, K05, K06, K07,
    CR0, CR1, CR2, CR3, CR4, CR5, CR6, CR7,
    RIP, RFG,

    NREGS
};

enum
{
    I_ADD, I_SUB, I_MUL, I_DIV, I_INC, I_DEC,
    I_AND, I_OR, I_XOR, I_NEG, I_CMD, I_TST,
    
    I_PUSH, I_PUSHF, I_PUSHA,
    I_POP, I_POPF, I_POPA,
    
    I_MOV, I_XCHG,

    I_BSWP,

    I_PSE, I_HLT, I_INT,

    NINSTRS
};

enum 
{
    GPR = 1 << 0,   // General
    CTL = 1 << 1,   // Control
    SEG = 1 << 2,   // Segment
    RES = 1 << 8,   // Reserved for insternal use
    SYS = 1 << 9,   // Reserved for supervisor mode
};

struct reg_t
{
    char   *name;
    char   *desc;
    ulong   val;
    ulong   flags;
};

enum { A_MEM=0x7000 };
struct acc_t
{
    bool mem;
    enum { A_REG=0, A_IMM16=0x7001, A_IMM32, A_IMM64 } type;
    
    ulong val;
};

enum { NOPREF, PREF_REP=0x8000, PREF_LOCK, NPREFS };

#define ISPREF(x) ((x) & 0x8000 && (x)<NPREFS)
#define ISINSTR(x)  ((x) < NINSTRS)

struct instr_t
{
    char   *name;
    uint    prms;
    void  (*func)(ctx_t *, acc_t *, acc_t *);
};

struct ctx_t
{
    reg_t   *r;
    instr_t *i;

    // Memory and memory size
    uchar  *mp;
    ulong   mz;

    // Read next instruction
    ushort (*get)(ctx_t *ctx);
};

enum
{
    E_ILL,          // Ill-formed
    E_IMP,          // Not implemented
    E_ACC,          // Invalid access
    E_SYS,          // Supervisor only
    E_SHT,          // Shutdown instruction
    NEXCPTS
};

void dumpregs(ctx_t *ctx);

static inline void _except(ctx_t *ctx, int code, char *str)
{
    log("Exception %d - %s\n", code, str);
    dumpregs(ctx);
    exit(code);
}

void decode(ctx_t *ctx);