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asm: adding instr_encode module

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This commit is contained in:
Henrik Hautakoski 2018-11-24 19:57:36 +01:00
parent 95f2e38c2d
commit 16501e40be
2 changed files with 77 additions and 0 deletions
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50
src/as/instr_encode.c Normal file
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/* instr_encode.c
*
* Copyright (C) 2018 Henrik Hautakoski <henrik@fiktivkod.org>
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <stdio.h>
#include <string.h>
#include "instr_encode.h"
void instr_encode(struct instr* instr, uint16_t *out) {
uint8_t *p = (uint8_t *) out;
*out = 0;
*p = instr->opcode << 4;
if (instr->opcode == OP_NOOP) {
// Do nothing.
} else if (instr->opcode == OP_JMP) {
*p |= (instr->j.addr >> 8);
*(p+1) = instr->j.addr;
} else {
*p |= instr->r.rs;
// I-Type
if (instr->opcode == OP_MOVL || instr->opcode == OP_MOVH
|| instr->opcode == OP_JR || instr->opcode == OP_INT) {
*(p+1) = instr->i.imm;
}
// R/RI-Type
else {
*(p+1) = (instr->r.r0 << 4) | instr->r.r1;
}
}
}