# procem_default
**procem_default** is a toy Rust library that provides a default implementation of the `Instruction` trait of the **procem** library.
## Instruction set
### Syntax
All instructions can be written in mixed case.
All operations that can be suffixed with an 'S', set the flag registers depending on the operation.
- *Labels* (**\<LABEL>**) are used to mark specific locations in the program. They are denoted using a dot ('.') followed by a string (e.g., '.label').
- *Registers* (**\<REG>**) must be a valid register name (e.g., 'R0', 'r1', 'R2', 'PC', 'sp').
- *Literals* (**\<LIT>**) are decimal, binary, hexadecimal, octal, boolean or char constants.
They are denoted using a '#' followed by a valid literal value.
- Decimal values start with '0d' (optional), followed by a sequence of '0's through '9's.
- Binary values start with '0b', followed by a sequence of '0's and '1's.
- Hexadecimal values start with '0x', followed by a sequence of digits from '0' through '9' and letters from 'a' through 'f'.
- Octal values start with '0o', followed by a sequence of '0's through '7's.
- Boolean values are either 'true' or 'false'.
- Character values are enclosed in single quotes, e.g., 'a', 'B', '5'.
- *Operands* (**\<OP>**) can be a register name or a literal.
'END' marks the end of the program. It is only used as a guide for the assembler and not part of the assembled program.
### Operations
- **NOP**: No operation.
- **MOV \<REG>, \<OP>**: Copy a value from the operand to the register.
- **PUSH \<OP>**: Push a value from the operand to the stack.
- **POP \<REG>**: Pop a value from the stack to the register.
- **CALL \<OP>**: Call a subroutine at the program address specified by the operand. Pushes the current program counter onto the stack and sets the program counter to the address of the subroutine.
- **RET**: Return from a subroutine. Pops the return address from the stack and sets the program counter to the popped value.
- **ADD\[S] \<REG>, \<OP>**: Add the value of the operand to the register. The result is stored in the register.
- **SUB\[S] \<REG>, \<OP>**: Subtract the value of the operand from the register. The result is stored in the register.
- **MUL\[S] \<REG>, \<OP>**: Multiply the value of the operand with the value of the register. The result is stored in the register.
- **DIV\[S] \<REG>, \<OP>**: Divide the value of the register by the value of the operand. The result is stored in the register.
- **INC\[S] \<REG>**: Increment the value in a register by one.
- **DEC\[S] \<REG>**: Decrement the value in a register by one.
- **JMP \<LABEL>**: Set program counter to the address of the label (first instruction after the label), effectively jumping to the instruction at this point in the program.
- **JZ \<LABEL>**: Jump to the label if the zero flag (Z) is set.
- **JNZ \<LABEL>**: Jump to the label if the zero flag (Z) is not set.
- **JC \<LABEL>**: Jump to the label if the carry flag (C) is set.
- **JNC \<LABEL>**: Jump to the label if the carry flag (C) is not set.
- **JS \<LABEL>**: Jump to the label if the signed flag (S) is set.
- **JNS \<LABEL>**: Jump to the label if the signed flag (S) is not set.
- **JG \<LABEL>**: Jump to the label if the zero flag (Z) and signed flag (S) are not set.
- **JGE \<LABEL>**: Jump to the label if the zero flag (Z) is set or signed flag (S) is not set.
- **JL \<LABEL>**: Jump to the label if the zero flag (Z) is not set and the signed flag (S) is set.
- **JLE \<LABEL>**: Jump to the label if the zero flag (Z) or signed flag (S) is set.
- **CMP \<OP>, \<OP>**: Compare the values of two operands and set the flags accordingly. This is the same as `SUBS` but disregards the result of the subtraction.
- **XOR \<REG>, \<OP>**: Perform a bitwise xor operation on the value in the register with the value of the operand.
- **AND \<REG>, \<OP>**: Perform a bitwise and operation on the value in the register with the value of the operand.
- **OR \<REG>, \<OP>**: Perform a bitwise or operation on the value in the register with the value of the operand.
- **NOT \<REG>**: Perform a bitwise not operation on the value in the register.
- **SHL \<REG>, \<LIT>**: Shift the value in the register left by the specified number of bits. Only use values between 1 and the number of bits of the Word size minus 1.
- **SHR \<REG>, \<LIT>**: Shift the value in the register right by the specified number of bits. Only use values between 1 and the number of bits of the Word size minus 1.
- **ROL \<REG>, \<LIT>**: Rotate the value in the register left by the specified number of bits. Only use values between 1 and the number of bits of the Word size minus 1.
- **ROR \<REG>, \<LIT>**: Rotate the value in the register right by the specified number of bits. Only use values between 1 and the number of bits of the Word size minus 1.
### Usage
To assemble a program from assembly code use the **assemble** function.
### Example
```rust
use procem::{processor::Processor, register::Register, word::I32};
use procem_default::assemble;
// Assemble a program from asm
let program = assemble::<I32>(
"
mov R0, #10
mov R1, #5
add R0, R1
sub R0, #3
mul R0, #2
div R0, #4
"
).unwrap();
// Create a processor and run the program
const STACK_SIZE: usize = 1024;
let mut processor = Processor::<STACK_SIZE, _, _, _>::builder()
.with_program(&program)
.build();
let _ = processor.run_program();
// Inspect register values
assert_eq!(processor.registers.get_reg(Register::R0), 6.into());
```