From beb2faa1ed5bb0fa66d0be966b774272a70b5528 Mon Sep 17 00:00:00 2001
From: Jason Hilder <jhilder95@gmail.com>
Date: Sat, 16 May 2026 09:13:38 +0200
Subject: [PATCH] Split files to domains.

---
 src/machine/cpu.odin     | 49 ++++++++++++++++++++++++++++++++++++++++
 src/machine/input.odin   |  3 +++
 src/machine/machine.odin | 30 ++----------------------
 src/machine/rom.odin     | 27 ++++++++++++++++++++++
 src/main.odin            |  3 +--
 5 files changed, 82 insertions(+), 30 deletions(-)
 create mode 100644 src/machine/cpu.odin
 create mode 100644 src/machine/input.odin
 create mode 100644 src/machine/rom.odin

diff --git a/src/machine/cpu.odin b/src/machine/cpu.odin
new file mode 100644
index 0000000..498c836
--- /dev/null
+++ b/src/machine/cpu.odin
@@ -0,0 +1,49 @@
+package machine
+
+import "core:log"
+
+// CPU.odin -> instructions, fetch, decode, execute, run loop
+
+cycle :: proc(s: ^System) {
+    program_counter := s.pc
+
+    // Fetch
+    // ---------------
+    high_byte :=  s.memory[program_counter]
+    low_byte :=   s.memory[program_counter + 1]
+
+    // advance past this instruction early for our next opcode
+    s.pc += 2
+
+    // Instructions are made of 2 bytes we combine the high and low byte
+    opcode := (u16(high_byte) << 8) | u16(low_byte)
+
+    // mask off everything except the first byte.
+    // shift it 12 bits 'back' left with the first number
+    kind := (opcode & 0xF000) >> 12
+
+    // Decode + Execute
+    // 1. opcodes are broken up to get their particulars
+    // 2. first nibble (4bits half byte) is the first hex number, this is the category
+    // ---------------
+    switch kind {
+    case 0x0:
+        switch opcode {
+            case 0x00E0: op_cls(s)
+        }
+    case 0x1: op_jp_add(s)
+    case 0xD: log.info("D instruction a draw call!")
+    }
+}
+
+// Instruction procs
+// -----------------------------------
+// CLS: Clear the display
+op_cls :: proc(s: ^System) {
+    log.info("found clear screen instruction, zero out display buffer")
+}
+
+// JP addr: Jump to location nnn
+op_jp_add :: proc(s: ^System) {
+    log.info("found jump instruction, set pc to nnn")
+}
diff --git a/src/machine/input.odin b/src/machine/input.odin
new file mode 100644
index 0000000..e21cec9
--- /dev/null
+++ b/src/machine/input.odin
@@ -0,0 +1,3 @@
+package machine
+
+// keypad mapping, input state update
diff --git a/src/machine/machine.odin b/src/machine/machine.odin
index a63ecc4..41c3967 100644
--- a/src/machine/machine.odin
+++ b/src/machine/machine.odin
@@ -1,8 +1,9 @@
 package machine
 
-import "core:os"
 import "core:log"
 
+//  System struct, init, constants, fontset
+
 System :: struct {
     // 4kb ram
     memory: [4096]u8,
@@ -55,30 +56,3 @@ init :: proc() -> System {
 
     return s
 }
-
-load_rom :: proc(s: ^System, file_path: string) -> os.Error {
-    log.info("Loading rom from file")
-
-    data, read_err := os.read_entire_file(file_path, context.allocator)
-    if read_err != os.ERROR_NONE {
-        log.errorf("failed to read rom %v", read_err)
-        return read_err
-    }
-    defer delete(data)
-
-    for byte,i in data {
-        s.memory[0x200 + i] = byte
-    }
-
-    log.infof("First few bytes: %X %X %X %X", s.memory[0x200], s.memory[0x201], s.memory[0x202], s.memory[0x203])
-
-    return nil
-}
-
-// fetch decode execute loop
-run :: proc(s: ^System) {
-    log.info("=== TODO loop ===")
-    // maybe needs a few functions for the 'screen' ie raylib.
-    // also a cycle function or something that will do the ops
-}
-
diff --git a/src/machine/rom.odin b/src/machine/rom.odin
new file mode 100644
index 0000000..98ce912
--- /dev/null
+++ b/src/machine/rom.odin
@@ -0,0 +1,27 @@
+package machine
+
+// load_rom, anything rom related
+
+import "core:log"
+import "core:os"
+
+load_rom :: proc(s: ^System, file_path: string) -> os.Error {
+    log.info("Loading rom from file")
+
+    data, read_err := os.read_entire_file(file_path, context.allocator)
+    if read_err != os.ERROR_NONE {
+        log.errorf("failed to read rom %v", read_err)
+        return read_err
+    }
+    defer delete(data)
+
+    for byte,i in data {
+        s.memory[0x200 + i] = byte
+    }
+
+    log.infof("First few bytes: %X %X %X %X", s.memory[0x200], s.memory[0x201], s.memory[0x202], s.memory[0x203])
+
+    return nil
+}
+
+
diff --git a/src/main.odin b/src/main.odin
index 78f3587..56ee903 100644
--- a/src/main.odin
+++ b/src/main.odin
@@ -5,7 +5,6 @@ import "core:mem"
 
 import chip "machine"
 
-// false = release default
 DEV :: #config(DEV, false)
 
 main :: proc() {
@@ -30,7 +29,7 @@ main :: proc() {
     }
 
     // start the cycle
-    chip.run(&system)
+    chip.init_display_and_cycle(&system)
 
     when DEV {
         if len(track.allocation_map) > 0 {