REDCODE(6) (5/20/84) REDCODE(6)
NAME
redcode - assembler for mars game
SYNOPSIS
redcode file1 file2 ...
DESCRIPTION
Redcode is an assembler for the Redcode assembly language
specified by Dr. Kee Dewdney in the "Computer Recreations"
column in the May 1984 issue of Scientific American. The
command line contains a list of source file names (including
the extension ".red") to be assembled. The result is a cor-
responding number of object files with extension ".obj".
For example, the following command:
redcode dwarf.red gemini.red imp.red
would assemble these three programs and create files
dwarf.obj gemini.obj imp.obj.
SOURCE FILES
A source file consists of a name directive which specifies
the program's name, followed by any number of program and
data statements, followed by an end directive which speci-
fies the starting location of the program. Statements have
the following syntax:
[label] opcode arg1 [arg2] [; comment]
ADDRESSING MODES
There are three addressing modes; all address calculations
are done modulo 8000.
Syntax Meaning
#[0-9]+ immediate
[0-9]+ relative
@[0-9]+ indirect, relative
OPCODES
The following opcodes are implemented, along with the corre-
sponding semantics specified in pseudo-C:
Instruction Mnem Opcode Args Explanation
Move mov 1 A B B=A
Add add 2 A B B+=A
Subtract sub 3 A B B-=A
Jump jmp 4 A PC=A
Jump if zero jmz 5 A B PC=(B==0)?A:PC+1
Jump if greater jmg 6 A B PC=(B<4000)?A:PC+1
REDCODE(6) (5/20/84) REDCODE(6)
Dec, Jmp if 0 djz 7 A B PC=(--B==0)?A:PC+1
Compare cmp 8 A B PC=(A==B)?PC+1:PC+2
PSEUDO-OPS
The following non-executable directives may be used to
reserve and initialize data space:
Directive Mnem Arg Explanation
Buffer space bss n Reserve n words
Data data A Initialize 1 word
Name name 't' Name of program
End end start Specify starting location
A SAMPLE REDCODE PROGRAM
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Dwarf, a sample Redcode program
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
name 'dwarf'
site data -1 ; address of last 0 'bomb'
start add #5 site ; move site forward
mov #0 @site ; write 0 'bomb'
jmp start ; loop
end start
OBJECT FILES
For documentation on the object code format, see mars(6).
SEE ALSO
mars(6)
HISTORY
20-May-84 Paul Milazzo (milazzo) at RICE
Created.