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68 lines
1.8 KiB
Markdown
68 lines
1.8 KiB
Markdown
---
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title: "05-6809-assembly"
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aliases:
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tags:
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- lecture
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- cosc204
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---
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# Warnings
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- different CPU architectures have their own machine codes and their own assembly languages
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- assembly language programs are **not** portable across CPU architectures (e.g., 6809 to x86 ARM) but are often backwards compatible (e.g., x86_64 family)
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# Working up
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- High level languages
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- ↓ Compiler ↓
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- Assembly language
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- ↓ Assembler ↓
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- Machine code
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- ↓ Instruction Set ↓
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- Hardware
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# Motorola MC6809 CPU
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- 6809 (1978) 9000 transistors
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- Apple M1 Ultra (2022) 114,000,000,000 transistors
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# Machine Code
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- Computers are controlled by bit-patterns.
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- These patterns determine what the CPU does and to which memory location
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- Assign values to registers
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- load registers from memory
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- add numbers to registers
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- store registers in memory
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- and so on
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- This is called machine code
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It is not very easy to programm this way
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- slow
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- not human readable
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- difficult to debug
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- etc
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To make the process easier, we assign names to the numbers. This allows us to program symbolically. We call this assembly language programming
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## Programmer's Model
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The programmer's model of a computer is not the same as the hardware model. The hardware makes the computer look a par
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## 6502 Fibonacci in Machine Code
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Example program:
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- 4C 13 00 00 00 00 00 00
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- 00 00 00 00 00 00 00 00
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- 00 00 00 A2 10 A9 01 8D
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- 10 00 8D 11 00 8D 12 00
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- A9 31 8D 0F 00 8D 0F 00
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- AD 10 00 6D 11 00 8D 12
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- 00 69 30 8D 0F 00 AD 11
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- 00 8D 10 00 AD 12 00 8D
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- 11 00 CA D0 E3
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[visualisation of comuter](http://www.visual6502.org/JSSim/expert.html?loglevel=0&a=0000&d=4C130000000000000000000000000000000000A210A9018D10008D11008D1200A9318D0F008D0F00AD10006D11008D120069308D0F00AD11008D1000AD12008D1100CAD0E3)
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