SAP 1 Emulator

From Digital Computer Electonics By Albert Malvino

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Description

SAP 1 (Simple As Possible) is a very basic model of microprocessor. It has only 5 basic instructions.

• 3 with 1 operand
• 2 with implicit operands

Instruction Set

Mnemonics	Operation	Op Code	Description
LDA	ACC 🠔 RAM[MAR]	0b0000	Load RAM data into accumulator
ADD	ACC 🠔 ACC + B	0b0001	Add RAM data to accumulator
SUB	ACC 🠔 ACC – B	0b0010	Subtract RAM data from accumulator
OUT	OUT 🠔 ACC	0b1100	Load accumulator data into output register
HLT	CLK 🠔 0	0b1111	Stop processing

Features

• Simple As Possible
• 16 Bytes Read Only Memory
• 8 Bit Bus

Register

1. Accumulator
2. B Register
3. Out Register
4. Instruction Register (IR)
5. Memory Address Register (MAR)

Architecture

Usage

For now the RAM is hardcoded in SAP1.cpp in form of vectors. Those instructions can be changed and then the solution can be built in Visual Studio to get executable binary.

 vector<byte> inst;
    inst.push_back(0x09);
    inst.push_back(0x1A);
    inst.push_back(0xEF);
    inst.push_back(0XFF);
    inst.push_back(0xFF);
    inst.push_back(0XFF);
    inst.push_back(0xFF);
    inst.push_back(0XFF);
    inst.push_back(0xFF);
    inst.push_back(0X04);
    inst.push_back(0x05);
    inst.push_back(0XFF);
    inst.push_back(0xFF);
    inst.push_back(0XFF);
    inst.push_back(0XFF);
    inst.push_back(0xFF);

To Do

• Adding More Comments ¯\( ͡° ͜ʖ ͡°)/¯
• Loading RAM from external file in Inetl hex format.
• Add T- states