vault backup: 2022-07-26 12:48:12

content/notes/05-6809-assembly.md

@@ -13,9 +13,55 @@ tags:
 
 # Working up
 - High level languages
-	- Compiler
+	- ↓ Compiler ↓
 - Assembly language
-	- Assembler
+	- ↓ Assembler ↓
 - Machine code
-	- Instruction Set
-- Hardware
+	- ↓ Instruction Set ↓
+- Hardware
+
+# Motorola MC6809 CPU
+- 6809 (1978) 9000 transistors
+- Apple M1 Ultra (2022) 114,000,000,000 transistors
+
+![Image of 6809 CPU chip](https://i.imgur.com/DuKNuX1.png)
+
+# Machine Code
+- Computers are controlled by bit-patterns. 
+- These patterns determine what the CPU does and to which memory location
+	- Assign values to registers
+	- load registers from memory
+	- add numbers to registers
+	- store registers in memory
+	- and so on
+- This is called machine code
+
+It is not very easy to programm this way
+- slow
+- not human readable
+- difficult to debug
+- etc
+
+To make the process easier, we assign names to the numbers. This allows us to program symbolically. We call this assembly language programming
+
+## Programmer's Model
+
+The programmer's model of a computer is not the same as the hardware model. The hardware makes the computer look a par
+
+## 6502 Fibonacci in Machine Code
+
+Example program:
+
+- 4C 13 00 00 00 00 00 00 
+- 00 00 00 00 00 00 00 00 
+- 00 00 00 A2 10 A9 01 8D 
+- 10 00 8D 11 00 8D 12 00 
+- A9 31 8D 0F 00 8D 0F 00 
+- AD 10 00 6D 11 00 8D 12 
+- 00 69 30 8D 0F 00 AD 11 
+- 00 8D 10 00 AD 12 00 8D 
+- 11 00 CA D0 E3
+
+[visualisation of comuter](http://www.visual6502.org/JSSim/expert.html?loglevel=0&a=0000&d=4C130000000000000000000000000000000000A210A9018D10008D11008D1200A9318D0F008D0F00AD10006D11008D120069308D0F00AD11008D1000AD12008D1100CAD0E3)
+
+