From 74992e673ac69021a7394fb1c4a860c8079aa987 Mon Sep 17 00:00:00 2001
From: SpookyDervish <nchand05@outlook.com>
Date: Thu, 16 Jul 2026 12:43:41 +1000
Subject: [PATCH] change SYS instruction to PORT and add imm4

---
 src/device.h      |  5 +++++
 src/emu.h         |  1 +
 src/instruction.c | 12 ++++++++++--
 src/instruction.h |  6 +++---
 4 files changed, 19 insertions(+), 5 deletions(-)
 create mode 100644 src/device.h

diff --git a/src/device.h b/src/device.h
new file mode 100644
index 0000000..2473ca0
--- /dev/null
+++ b/src/device.h
@@ -0,0 +1,5 @@
+#pragma once
+
+typedef struct {
+
+} Device;
\ No newline at end of file
diff --git a/src/emu.h b/src/emu.h
index 294a4ce..672be73 100644
--- a/src/emu.h
+++ b/src/emu.h
@@ -5,6 +5,7 @@
 #include <string.h>
 #include <stdbool.h>
 #include "memory.h"
+#include "device.h"
 
 #define FLAG_ZERO (1 << 0)
 #define FLAG_NEGATIVE (1 << 1)
diff --git a/src/instruction.c b/src/instruction.c
index 216c12b..a4f8f2e 100644
--- a/src/instruction.c
+++ b/src/instruction.c
@@ -15,7 +15,7 @@ const OperandType INSTRUCTION_OPERAND_TYPES[][3] = {
     {OP_REG, OP_REG,  OP_NONE},   // JIZ
     {OP_REG, OP_REG,  OP_NONE},   // CALL
     {OP_NONE, OP_NONE,  OP_NONE}, // RET
-    {OP_REG, OP_REG,  OP_REG},    // SYS
+    {OP_REG, OP_REG,  OP_IMM4},   // PORT
     {OP_NONE, OP_NONE,  OP_NONE}  // HLT
 };
 
@@ -35,7 +35,7 @@ char* opcodeToCStr(InstructionOpcode opcode) {
         case INST_JIZ:   return "JIZ";
         case INST_CALL:  return "CALL";
         case INST_RET:   return "RET";
-        case INST_SYS:   return "SYS";
+        case INST_PORT:  return "PORT";
         case INST_HLT:   return "HLT";
         default:         return "FIXME";
     }
@@ -81,6 +81,14 @@ char* instructionToCStr(Instruction inst) {
                     registerToCStr(inst.operands[opIdx])
                 );
                 break;
+            case OP_IMM4: 
+                written += snprintf(
+                    buffer + written,
+                    remaining,
+                    "%d",
+                    inst.operands[opIdx]
+                );
+                break;
             case OP_IMM16:
                 written += snprintf(
                     buffer + written,
diff --git a/src/instruction.h b/src/instruction.h
index f49e7e1..0a4dfaa 100644
--- a/src/instruction.h
+++ b/src/instruction.h
@@ -7,8 +7,8 @@
 
 // -- TYPES -- //
 typedef enum : uint8_t {
-    INST_MOV, INST_MVI, INST_ADD, INST_SUB, INST_LOAD, INST_STORE, INST_AND, INST_OR,
-    INST_XOR, INST_SHF, INST_JMP, INST_JIZ, INST_CALL, INST_RET,   INST_SYS, INST_HLT
+    INST_MOV, INST_MVI, INST_ADD, INST_SUB, INST_LOAD, INST_STORE, INST_AND,  INST_OR,
+    INST_XOR, INST_SHF, INST_JMP, INST_JIZ, INST_CALL, INST_RET,   INST_PORT, INST_HLT
 } InstructionOpcode;
 
 typedef enum {
@@ -38,7 +38,7 @@ typedef struct {
 } Instruction;
 
 typedef enum {
-    OP_NONE, OP_REG, OP_IMM16
+    OP_NONE, OP_REG, OP_IMM4, OP_IMM16
 } OperandType;
 
 // -- CONSTANTS -- //