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Fix Intel 4004 CPU emulation bugs: opcode mapping, JCN conditions, DAA carry

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- Remap opcodes 0x01-0x0F from duplicate LD to Invalid (undefined on real hardware)
- Fix JCN condition bit mapping per datasheet: C1=Carry, C2=ACC zero, C3=TEST pin
- Fix DAA instruction to clear carry when no 4-bit overflow occurs
- Rewrite fibonacci demo program with correct opcodes (FIM, CLB, LD, ADD, WRM, XCH, ISZ)
- Regenerate fibonacci.bin and fibonacci_output.bin with correct opcodes
- Update all tests to match corrected JCN condition codes
- Update plan document and README to reflect changes
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Jan-Peter von Hunnius 2026-05-12 20:55:26 +02:00
parent 6a335a15d4
commit add7ace674
7 changed files with 132 additions and 100 deletions
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18
programs/README.md
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@ -5,18 +5,18 @@ This directory contains binary program files for the Intel MCS-4 emulator.
## Available Programs
### fibonacci.bin
- **Size:** 33 bytes (16 instructions × 2 bytes each + 1 extra byte)
- **Description:** Basic Fibonacci sequence generator (stores results in RAM)
- **Algorithm:** Calculates first 8 Fibonacci numbers using registers and RAM
- **Instructions Used:** LDM, LD, WRM, IAC, ADD, JCN, NOP
- **Output:** Results stored in RAM locations 0-7 (not visible to user)
- **Size:** 17 bytes
- **Description:** Fibonacci sequence generator (stores results in RAM)
- **Algorithm:** Calculates first 8 Fibonacci numbers using registers R0-R3 and RAM
- **Instructions Used:** FIM, CLB, LD, ADD, WRM, XCH, ISZ, NOP
- **Output:** Results stored in RAM via WRM
### fibonacci_output.bin ✨ **RECOMMENDED**
- **Size:** 55 bytes (27 instructions × 2 bytes each + 1 extra byte)
- **Size:** 23 bytes
- **Description:** Enhanced Fibonacci sequence generator with output port visibility
- **Algorithm:** Calculates first 8 Fibonacci numbers and outputs them to output ports
- **Instructions Used:** LDM, LD, WRM, IAC, ADD, JCN, NOP, SRC
- **Output:** Each Fibonacci number visible on output ports 0-7 during execution
- **Algorithm:** Calculates first 8 Fibonacci numbers and outputs them to RAM + output ports
- **Instructions Used:** FIM, CLB, LD, ADD, WRM, WMP, XCH, SRC, ISZ, NOP
- **Output:** Each Fibonacci number visible on output ports during execution
- **Features:** Real-time visibility of calculation progress
### io_demo.bin ✨ **NEW**