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/* Copyright (C) 2023 Aryadev Chavali
* You may distribute and modify this code under the terms of the
* GPLv2 license. You should have received a copy of the GPLv2
* license with this file. If not, please write to:
* aryadev@aryadevchavali.com.
* Created: 2023-10-15
* Author: Aryadev Chavali
* Description: Implementation of bytecode for instructions
*/
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include "./inst.h"
const char *opcode_as_cstr(opcode_t code)
{
switch (code)
{
case OP_NOOP:
return "NOOP";
break;
case OP_PUSH_BYTE:
return "PUSH_BYTE";
break;
case OP_PUSH_WORD:
return "PUSH_WORD";
break;
case OP_PUSH_HWORD:
return "PUSH_HWORD";
break;
case OP_PUSH_REGISTER_BYTE:
return "PUSH_REGISTER_BYTE";
break;
case OP_PUSH_REGISTER_WORD:
return "PUSH_REGISTER_WORD";
break;
case OP_PUSH_REGISTER_HWORD:
return "PUSH_REGISTER_HWORD";
break;
case OP_POP_BYTE:
return "POP_BYTE";
break;
case OP_POP_WORD:
return "POP_WORD";
break;
case OP_POP_HWORD:
return "POP_HWORD";
break;
case OP_MOV_BYTE:
return "MOV_BYTE";
break;
case OP_MOV_WORD:
return "MOV_WORD";
break;
case OP_MOV_HWORD:
return "MOV_HWORD";
break;
case OP_HALT:
return "HALT";
break;
}
return "";
}
void data_print(data_t datum, data_type_t type, FILE *fp)
{
switch (type)
{
case DATA_TYPE_NIL:
break;
case DATA_TYPE_BYTE:
fprintf(fp, "%X", datum.as_byte);
break;
case DATA_TYPE_HWORD:
fprintf(fp, "%d", datum.as_hword);
break;
case DATA_TYPE_WORD:
fprintf(fp, "%lX", datum.as_word);
break;
}
}
data_type_t get_opcode_data_type(opcode_t opcode)
{
data_type_t type = DATA_TYPE_NIL;
if (OPCODE_IS_TYPE(opcode, OP_PUSH))
type = (data_type_t)opcode;
else if (OPCODE_IS_TYPE(opcode, OP_PUSH_REGISTER))
type = opcode >> 1;
else if (OPCODE_IS_TYPE(opcode, OP_POP))
type = opcode >> 2;
else if (OPCODE_IS_TYPE(opcode, OP_MOV))
type = opcode >> 3;
return type;
}
void inst_print(inst_t instruction, FILE *fp)
{
fprintf(fp, "(%s", opcode_as_cstr(instruction.opcode));
if (OPCODE_IS_TYPE(instruction.opcode, OP_PUSH))
{
data_type_t type = get_opcode_data_type(instruction.opcode);
fprintf(fp, ", datum=0x");
data_print(instruction.operand, type, fp);
}
else if (OPCODE_IS_TYPE(instruction.opcode, OP_PUSH_REGISTER) ||
OPCODE_IS_TYPE(instruction.opcode, OP_MOV))
{
fprintf(fp, ", reg=0x");
data_print(instruction.operand, DATA_TYPE_BYTE, fp);
}
fprintf(fp, ")");
}
size_t inst_bytecode_size(inst_t inst)
{
size_t size = 1; // for opcode
if (OPCODE_IS_TYPE(inst.opcode, OP_PUSH))
{
if (inst.opcode == OP_PUSH_BYTE)
++size;
else if (inst.opcode == OP_PUSH_HWORD)
size += sizeof(i32);
else if (inst.opcode == OP_PUSH_WORD)
size += sizeof(word);
}
else if (OPCODE_IS_TYPE(inst.opcode, OP_PUSH_REGISTER) ||
OPCODE_IS_TYPE(inst.opcode, OP_MOV))
// Only need a byte for the register
++size;
else if (OPCODE_IS_TYPE(inst.opcode, OP_POP))
// No operand or register so leave as is
{}
return size;
}
void inst_write_bytecode(inst_t inst, darr_t *darr)
{
// Append opcode
darr_append_byte(darr, inst.opcode);
// Then append 0 or more operands
data_type_t to_append = DATA_TYPE_NIL;
if (OPCODE_IS_TYPE(inst.opcode, OP_PUSH))
to_append = (data_type_t)inst.opcode;
else if (OPCODE_IS_TYPE(inst.opcode, OP_PUSH_REGISTER) ||
OPCODE_IS_TYPE(inst.opcode, OP_MOV))
to_append = DATA_TYPE_BYTE;
switch (to_append)
{
case DATA_TYPE_NIL:
break;
case DATA_TYPE_BYTE:
darr_append_byte(darr, inst.operand.as_byte);
break;
case DATA_TYPE_HWORD:
darr_append_bytes(darr, (byte *)&inst.operand.as_hword,
sizeof(inst.operand.as_hword));
break;
case DATA_TYPE_WORD:
darr_append_bytes(darr, (byte *)&inst.operand.as_word,
sizeof(inst.operand.as_word));
break;
}
}
data_t read_type_from_darr(darr_t *darr, data_type_t type)
{
switch (type)
{
case DATA_TYPE_NIL:
break;
case DATA_TYPE_BYTE:
if (darr->used >= darr->available)
// TODO: Error (darr has no space left)
return DBYTE(0);
return DBYTE(darr->data[darr->used++]);
break;
case DATA_TYPE_HWORD:
if (darr->used + HWORD_SIZE >= darr->available)
// TODO: Error (darr has no space left)
return DWORD(0);
hword u = 0;
memcpy(&u, darr->data + darr->used, sizeof(u));
darr->used += sizeof(u);
return DHWORD(u);
break;
case DATA_TYPE_WORD:
if (darr->used + sizeof(word) >= darr->available)
// TODO: Error (darr has no space left)
return DWORD(0);
word w = 0;
memcpy(&w, darr->data + darr->used, sizeof(w));
darr->used += sizeof(w);
return DWORD(w);
break;
}
// TODO: Error (unrecognised type)
return DBYTE(0);
}
inst_t inst_read_bytecode(darr_t *darr)
{
if (darr->used >= darr->available)
return (inst_t){0};
inst_t inst = {0};
opcode_t opcode = darr->data[darr->used++];
if (opcode > OP_HALT)
// Translate to NOOP
return inst;
// Read operands
if (OPCODE_IS_TYPE(opcode, OP_PUSH))
inst.operand = read_type_from_darr(darr, get_opcode_data_type(opcode));
// Read register (as a byte)
else if (OPCODE_IS_TYPE(opcode, OP_PUSH_REGISTER) ||
OPCODE_IS_TYPE(opcode, OP_MOV))
inst.operand = read_type_from_darr(darr, DATA_TYPE_BYTE);
// Otherwise opcode doesn't take operands
inst.opcode = opcode;
return inst;
}
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