#ifndef TVM_H_
#define TVM_H_

#include <stddef.h>

#include "tvm_file.h"
#include "tvm_preprocessor.h"
#include "tvm_stack.h"

#include "tvm_memory.h"
#include "tvm_program.h"
#include "tvm_tokens.h"

struct tvm_ctx {
	struct tvm_prog *prog;
	struct tvm_mem *mem;
};

struct tvm_ctx *tvm_vm_create();
void tvm_vm_destroy(struct tvm_ctx *vm);

int tvm_vm_interpret(struct tvm_ctx *vm, char *filename);
void tvm_vm_run(struct tvm_ctx *vm);

static inline void tvm_step(struct tvm_ctx *vm, int *instr_idx)
{
	int **args = vm->prog->args[*instr_idx];

	switch (vm->prog->instr[*instr_idx]) {
/* nop   */	case 0x0:  break;
/* int   */	case 0x1:  /* unimplemented */ break;
/* mov   */	case 0x2:  *args[0] = *args[1]; break;
/* push  */	case 0x3:  tvm_stack_push(vm->mem, args[0]); break;
/* pop   */	case 0x4:  tvm_stack_pop(vm->mem, args[0]); break;
/* pushf */	case 0x5:  tvm_stack_push(vm->mem, &vm->mem->FLAGS); break;
/* popf  */	case 0x6:  tvm_stack_pop(vm->mem, args[0]); break;
/* inc   */	case 0x7:  ++(*args[0]); break;
/* dec   */	case 0x8:  --(*args[0]); break;
/* add   */	case 0x9:  *args[0] += *args[1]; break;
/* sub   */	case 0xA:  *args[0] -= *args[1]; break;
/* mul   */	case 0xB:  *args[0] *= *args[1]; break;
/* div   */	case 0xC:  *args[0] /= *args[1]; break;
/* mod   */	case 0xD:  vm->mem->remainder = *args[0] % *args[1]; break;
/* rem   */	case 0xE:  *args[0] = vm->mem->remainder; break;
/* not   */	case 0xF:  *args[0] = ~(*args[0]); break;
/* xor   */	case 0x10:  *args[0] ^= *args[1];  break;
/* or    */	case 0x11: *args[0] |= *args[1];   break;
/* and   */	case 0x12: *args[0] &= *args[1];   break;
/* shl   */	case 0x13: *args[0] <<= *args[1];  break;
/* shr   */	case 0x14: *args[0] >>= *args[1];  break;
/* cmp   */	case 0x15: vm->mem->FLAGS =
				((*args[0] == *args[1]) | (*args[0] > *args[1]) << 1);
				break;
/* call	 */	case 0x17: tvm_stack_push(vm->mem, instr_idx);
/* jmp	 */	case 0x16: *instr_idx = *args[0] - 1; break;
/* ret   */	case 0x18: tvm_stack_pop(vm->mem, instr_idx);
				break;
/* je    */	case 0x19:
				*instr_idx = (vm->mem->FLAGS & 0x1)
					? *args[0] - 1 : *instr_idx;
				break;
/* jne   */	case 0x1A:
				*instr_idx = (!(vm->mem->FLAGS & 0x1))
					? *args[0] - 1 : *instr_idx;
				break;
/* jg    */	case 0x1B:
				*instr_idx = (vm->mem->FLAGS & 0x2)
					? *args[0] - 1 : *instr_idx;
				break;
/* jge   */	case 0x1C:
				*instr_idx = (vm->mem->FLAGS & 0x3)
					? *args[0] - 1 : *instr_idx;
				break;
/* jl    */	case 0x1D:
				*instr_idx = (!(vm->mem->FLAGS & 0x3))
					? *args[0] - 1 : *instr_idx;
				break;
/* jle   */	case 0x1E:
				*instr_idx = (!(vm->mem->FLAGS & 0x2))
					? *args[0] - 1 : *instr_idx;
				break;
/* prn   */	case 0x1F: printf("%i\n", *args[0]);
	};
}

#endif