From 34e2c24b88e74e3f1833306ab23eead7b06d35b0 Mon Sep 17 00:00:00 2001
From: n loewen <n@nloewen.com>
Date: Fri, 28 Feb 2025 10:48:47 +0000
Subject: [PATCH] Start working on micropython simulator for 2025 version of
 cardiograph

---
 src/cpu.mpy | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 src/cpu.mpy

diff --git a/src/cpu.mpy b/src/cpu.mpy
new file mode 100644
index 0000000..85d8cf4
--- /dev/null
+++ b/src/cpu.mpy
@@ -0,0 +1,49 @@
+class CPU:
+  def __init__(self):
+    self.running = False
+    self.IP = 254
+    self.acc = 0
+    self.flags = { 'C': False, 'Z': False, 'N': False, 'Eq': False }
+    self.instruction = { 'opcode': False, 'operand': False }
+    self.memory = False
+
+  def load_memory(self, bytes):
+    self.memory = bytes + bytearray(256 - len(bytes))
+    print(self.memory)
+
+  def step(self):
+    if self.IP >= 256:
+      self.IP = 0
+    print(self.IP)
+    self.instruction['opcode'] = self.memory[self.IP]
+    self.IP = self.IP+1
+    self.instruction['operand'] = self.memory[self.IP]
+    self.IP = self.IP+1
+    print(self.instruction)
+ 
+  nums2mnems = {
+    'hlt': '00',
+    'nop': '01',
+    'add_lit': '04'
+  }
+    
+  def hlt(self):
+    self.running = false
+
+  def nop(self):
+    pass
+
+  def add_lit(num):
+    self.acc = self.acc + num
+
+cpu = CPU()
+print(cpu)
+print(cpu.running)
+
+prog = '04 01 14 01 00 00'
+b = bytes.fromhex(prog)
+cpu.load_memory(b)
+
+cpu.step()
+cpu.step()
+cpu.step()