#ifndef ZRE_OPCODES_H
#define ZRE_OPCODES_H

#include "common.h"

typedef union {
  int32_t i;  /* Integers */
  float f;    /* Float */
  uint32_t u; /* Unsigned integers, also used for pointer address */
  char c[4];  /* 4 Byte char array for string packing */
} Value;

typedef struct {
  uint32_t start;
  uint32_t end;
} Slice;

#define MAX_REGS 32
typedef struct {
  Value registers[MAX_REGS]; /* R0-R31 */
  uint32_t rp;               /* register pointer (last unused) */
  Slice allocated;           /* start and end of global allocated block */
} Frame;

#define MEMORY_SIZE 65536
#define FRAMES_SIZE 128 
#define STACK_SIZE 256
typedef struct {
  uint32_t pc; /* Program counter */
  uint32_t fp; /* Frame pointer plast allocated value) */
  uint32_t sp; /* stack pointer (top of stack) */
  uint32_t rp; /* return stack pointer (top of stack) */
  uint32_t mp; /* Memory pointer (last allocated value) */
  uint32_t frames_size;
  Frame frames[FRAMES_SIZE]; /* function call frames */
  uint32_t stack_size;
  Value stack[STACK_SIZE]; /* main stack */
  uint32_t return_stack_size;
  Value return_stack[STACK_SIZE]; /* return stack (for recursion) */
  uint32_t memory_size;
  Value memory[MEMORY_SIZE]; /* memory array */
} VM;

typedef enum {
  OP_HALT,    /* halt : terminate execution */
  OP_LOADI,   /* lodi : dest = next memory location as int */
  OP_LOADU,   /* lodu : dest = next memory location as uint */
  OP_LOADF,   /* lodf : dest = next memory location as float */
  OP_STOREI,  /* stri : next memory location = src1 as int */
  OP_STOREU,  /* stru : next memory location = src1 as uint */
  OP_STOREF,  /* strf : next memory location = src1 as float */
  OP_PUSHI,   /* pshi : push int from register onto the stack */
  OP_PUSHU,   /* pshu : push uint from register onto the stack */
  OP_PUSHF,   /* pshf : push float from register onto the stack */
  OP_PUSHS,   /* pshs : push str ref from register onto the stack and copy str  */
  OP_POPI,    /* popi : pop int from stack onto the register */
  OP_POPU,    /* popu : pop uint from stack onto the register */
  OP_POPF,    /* popf : pop float from stack onto the register */
  OP_POPS,    /* pops : pop str ref from stack and move/copy to register */
  OP_ADD_INT, /* addi : dest = src1 + src2  */
  OP_SUB_INT, /* subi : dest = src1 - src2  */
  OP_MUL_INT, /* muli : dest = src1 * src2  */
  OP_DIV_INT, /* divi : dest = src1 / src2  */
  OP_JEQ_INT, /* jeqi : jump to address dest if src1 as int == src2 as int */
  OP_JGT_INT, /* jgti : jump to address dest if src1 as int > src2 as int*/
  OP_JLT_INT, /* jlti : jump to address dest if src1 as int < src2 as int */
  OP_JLE_INT, /* jlei : jump to address dest if src1 as int <= src2 as int */
  OP_JGE_INT, /* jgei : jump to address dest if src1 as int >= src2 as int*/
  OP_INT_TO_REAL, /* itor : dest = src1 as f32  */
  OP_ADD_UINT,    /* addu : dest = src1 + src2  */
  OP_SUB_UINT,    /* subu : dest = src1 - src2  */
  OP_MUL_UINT,    /* mulu : dest = src1 * src2  */
  OP_DIV_UINT,    /* divu : dest = src1 / src2  */
  OP_JEQ_UINT, /* jequ : jump to address dest if src1 as int == src2 as uint */
  OP_JGT_UINT, /* jgtu : jump to address dest if src1 as int > src2 as uint*/
  OP_JLT_UINT, /* jltu : jump to address dest if src1 as int < src2 as uint */
  OP_JLE_UINT, /* jleu : jump to address dest if src1 as int <= src2 as uint */
  OP_JGE_UINT, /* jgeu : jump to address dest if src1 as int >= src2 as uint*/
  OP_UINT_TO_REAL, /* utor : dest = src1 as f32  */
  OP_ADD_REAL,     /* addr : dest = src1 + src2  */
  OP_SUB_REAL,     /* subr : dest = src1 - src2  */
  OP_MUL_REAL,     /* mulr : dest = src1 * src2  */
  OP_DIV_REAL,     /* divr : dest = src1 / src2  */
  OP_JEQ_REAL, /* jeqr : jump to address dest if src1 as real == src2 as real */
  OP_JGE_REAL, /* jgtr : jump to address dest if src1 as real >= src2 as real */
  OP_JGT_REAL, /* jltr : jump to address dest if src1 as real > src2 as real */
  OP_JLT_REAL, /* jler : jump to address dest if src1 as real < src2 as real */
  OP_JLE_REAL, /* jger : jump to address dest if src1 as real <= src2 as real */
  OP_REAL_TO_INT,    /* rtoi : dest = src1 as int  */
  OP_REAL_TO_UINT,   /* rtou : dest = src1 as uint  */
  OP_MOV,            /* move : dest = src1	   */
  OP_JMP,            /* jump : jump to address src1 unconditionally */
  OP_CALL,           /* call : creates a new frame */
  OP_RETURN,         /* retn : returns from a frame to the parent frame */
  OP_INT_TO_STRING,  /* itos : dest = src1 as str */
  OP_UINT_TO_STRING, /* utos : dest = src1 as str */
  OP_REAL_TO_STRING, /* rtos : dest = src1 as str */
  OP_READ_STRING,    /* gets : dest = gets as str */
  OP_PRINT_STRING,   /* puts : write src1 to stdout */
  OP_CMP_STRING,     /* cmps : dest = (str == src2) as bool */
} Opcode;

/* defines a uint32 opcode */
#define OP(opcode, a, b, c) ((opcode << 24) | (a << 16) | (b << 8) | c)

#endif