Parser
Redcode is converted to a load format by a parser before being loaded into the Corewar simulator.
The parser performs the following functions:
- Checks for syntax errors
- Inserts default modifiers and addressing modes
- Replaces labels with addresses
- Executes preprocessor commands
- Removes white space and comments
Defaults
All instructions require a modifier and two operands in order to be loaded into the Simulator. Each operand must have an addressing mode and a number.
However, it is not necessary to specify modifiers or addressing modes in order for an instruction to be successfully parsed. If you omit the modifier or addressing modes from an instruction, the parser will insert the default value in the load file output.
For example when parsed mov 0, 1 will become MOV.I $0, $1.
Addressing Modes
The default addressing mode is direct ($) for all opcodes except dat. Instructions with the dat opcode default to the immediate (#) addressing mode.
Operands
If an instruction has only a single operand, the B operand is defaulted to zero. Only the dat, jmp, spl and nop opcodes can have a single operand specified. Failure to specify a B operand for other opcodes will result in a syntax error.
Modifiers
Which modifier is inserted as a default is dependant upon the instruction's opcode and A and B addressing modes as follows:
| Opcode | A-mode | B-mode | Default Modifier |
|---|---|---|---|
dat |
any | any | .f |
mov cmp |
# | any | .ab |
| $@<>{} | # | .b |
|
| $@<>{} | $@<>{} | .i |
|
add sub mul div mod |
# | any | .ab |
| $@<>{} | # | .b |
|
| $@<>{} | $@<>{} | .f |
|
slt |
# | any | .ab |
| $@<>{} | any | .b |
|
jmp jmz jmn djn spl nop |
any | any | .b |