An IAS Machine Assembler. Translates "IASlang" mnemonic codes into opcodes, executed on the IAS computer.
Objective • Manual • Language • Versions • Licence • Developer
The main objective is to facilitate learning on the subject of Computer Architecture and Organization through the use of programming for the IAS computer, using mnemonic instructions, similar to Assembly, as an introduction.
The use of the IAS computer is interesting in learning computer architectures, but its programming is complicated, mainly due to the use of numeric opcodes for this. This project brings a relatively powerful and simple assembler, which will assist in learning, through mnemonic instructions.
This programm was compiled in a Ubuntu 20.04, therefore it will only run in a linux-based kernel. To run in other kernel you must compile it. In the root directory do:
make it
The binary will me in bin/ folder. Then, you must run it with at least one parameter, up to two, in the following fashion:
./bin/iaspie input.ias output.txt
Where "input.ias" is the file with the IASlang mnemonics, you must put this, where the extension must be ".ias", and "output.txt" is the file where the opcodes will be placed, an optional parameter. Done this you can test the program in the following simulator. Place the generated code in the box, press the load button and run it.
There are 22 instructions, as showed bellow. There are some restraints: all procedures must begin with "_" and end with a ":". All variable labels must, as well, end with ":". You can write one line commentaries with "#". The variables must be placed in data section, thats it, bellow the diretive ".data", anda the instructions must be placed in the code section, bellow ".code". The data sextion must be bellow the coode section.
This initial programm version accept up to 10 procedures and 232 variables.
| Opcode | Instruction Type | Mnemonic | Operation | Description |
|---|---|---|---|---|
| 0x00 | Exit | HALT | - | Halt the program execution. Will abort the simulator with "invalidInstruction" exception. |
| 0x01 | Data Transfer | LDM mem | LOAD M(x) | Load variable mem to AC register. |
| 0x02 | Data Transfer | LDMn mem | LOAD -M(x) | Load variable negative mem to AC register. |
| 0x03 | Data Transfer | LDMa mem | LOAD |M(x)| | Load variable module mem to AC register. |
| 0x04 | Data Transfer | LDMan mem | LOAD -|M(x)| | Load variable negative module mem to AC register. |
| 0x05 | Arithmetic | ADD mem | ADD M(x) | Add variable mem to AC register. |
| 0x06 | Arithmetic | SUB mem | SUB M(x) | Sub variable mem to AC register. |
| 0x07 | Arithmetic | ADDa mem | ADD |M(x)| | Add the module of variable mem to AC register. |
| 0x08 | Arithmetic | SUBa mem | SUB |M(x)| | Sub the module of variable mem to AC register. |
| 0x09 | Data Transfer | LDA mem | LOAD MQ, M(x) | Load variable mem to MQ register. |
| 0x0A | Data Transfer | LDQ | LOAD MQ | Load MQ register to AC register. |
| 0x0B | Arithmetic | MUL mem | MUL M(x) | Multiply variable mem by MQ register. The most significant bit will be in AC and the least in MQ. |
| 0x0C | Arithmetic | DIV mem | DIV M(x) | Divide AC register by variable mem. The quocient will be in MQ and the remainder in AC. |
| 0x0D | Unconditional Branch | JMPT proc | JUMP M(x, 0:19) | Branch to the first instruction of the proc procedure. |
| 0x0E | Unconditional Branch | JMPB proc | JUMP M(x, 20:39) | Branch to the second instruction of the proc procedure. |
| 0x0F | Conditional Branch | JMPTs proc | JUMP+ M(x, 0:19) | Branch to the first instruction of the proc procedure if AC is nonnegative. |
| 0x10 | Conditional Branch | JMPBs proc | JUMP+ M(x, 20:39) | Branch to the second instruction of the proc procedure if AC is nonnegative. |
| 0x12 | Address Modify | RPLT proc | STOR M(x, 8:19) | Replace the first instruction's operand, of the proc procedure, with the 12 rightmost bits of AC. |
| 0x13 | Address Modify | RPLB proc | STOR M(x, 28:39) | Replace the second instruction's operand, of the proc procedure, with the 12 rightmost bits of AC. |
| 0x14 | Arithmetic | LSH | LSH | Shift AC register one bit to the left. |
| 0x15 | Arithmetic | RSH | RSH | Shift AC register one bit to the right. |
| 0x21 | Data Transfer | STR mem | STOR M(x) | Store AC contents in mem. |
There are 2 directives in the IASlang:
| Diretive Type | Directive | Description |
|---|---|---|
| Delimiter | .code | Delimits the code segment in the program's memory. |
| Delimiter | .data | Delimits the data segment in the program's memory. |
There are a few programs in examples/ folder. Check it out.
The language that was used was C++.
IASpie Alpha v0.1: Initial commit. Some minor error handling messages. Parameters by terminal, one required, up to two: input file, with ".ias" extension, and a optional output file. In case of no output file, the output file will have the same name as the input, with the ".txt" extension. Some Fatal Errors:
- No input file;
- More than two parameters;
- Input file doesn't exist;
- Input file invalid extension;
- Section directives misplaced or missing;
- Instruction placed in data section;
- More than one HALT instruction;
- Bad procedure name, it must begin with "_" and end with ":";
- Duplicate procedure name;
- Invalid variable value;
- Duplicate variable name;
This program is still in the testing phase. Help in the development, reporting any error to the developer.
Under the GNU General Public License v3.0.
My name is Pedro M. Botelho. I'm a computer enginner stundent at Federal University of Ceará, in Brazil. For more informations, or to report some error, send an emain to pedrobotelho15@alu.ufc.br.