( This is a comment ) ( All programming in Unxtal is done by manipulating the stack ) #12 ( push a byte ) #3456 ( push a short ) ( Uxn has 32 opcodes, each opcode has 3 possible modes ) POP ( pop a byte ) POP2 ( pop a short ) ( The modes are: [2] The short mode consumes two bytes from the stack. [k] The keep mode does not consume items from the stack. [r] The return mode makes the operator operate on the return-stack. ) #12 #34 ADD ( 46 ) #12 #34 ADDk ( 12 34 46 ) ( The modes can be combined ) #1234 #5678 ADD2k ( 12 34 56 78 68 ac ) ( The arithmetic/bitwise opcodes are: ADD SUB MUL DIV AND ORA EOR SFT ) ( New opcodes can be created using macros ) %MOD2 { DIV2k MUL2 SUB2 } #1234 #0421 MOD2 ( 01 b0 ) ( ---------------------------------------------------------------------------- ) ( A short is simply two bytes, each byte can be manipulated ) #1234 SWP ( 34 12 ) #1234 #5678 SWP2 ( 56 78 12 34 ) #1234 #5678 SWP ( 12 34 78 56 ) ( Individual bytes of a short can be removed from the stack ) #1234 POP ( 12 ) #1234 NIP ( 34 ) ( The stack opcodes are: POP DUP NIP SWP OVR ROT ) ( ---------------------------------------------------------------------------- ) ( To compare values on the stack with each other ) #12 #34 EQU ( 00 ) #12 #12 EQU ( 01 ) ( Logic opcodes will put a flag with a value of either 00 or 01 ) #12 #34 LTH #78 #56 GTH #0101 EQU2 ( 01 ) ( The logic opcodes are: EQU NEQ GTH LTH ) ( ---------------------------------------------------------------------------- ) ( Uxn's accessible memory is as follows: 256 bytes of working stack 256 bytes of return stack 65536 bytes of memory 256 bytes of IO memory ) ( The addressable memory is between 0000-ffff ) #12 #0200 STA ( stored 12 at 0200 in memory ) #3456 #0201 STA2 ( stored 3456 at 0201 in memory ) #0200 LDA2 ( 12 34 ) ( The zero-page can be addressed with a single byte ) #1234 #80 STZ2 ( stored 12 at 0080, and 34 at 0081 ) #80 LDZ2 ( 12 34 ) ( Devices are ways for Uxn to communicate with the outside world There is a maximum of 16 devices connected to Uxn at once Device bytes are called ports, the Console device uses the 10-1f ports The console's port 18 is called /write ) %EMIT { #18 DEO } #31 EMIT ( print "1" to console ) ( A label is equal to a position in the program ) @parent ( defines a label "parent" ) &child ( defines a sublabel "parent/child" ) ( Label positions can be pushed on stack ) ;parent ( push the absolute position, 2 bytes ) ,parent ( push the relative position, 1 byte ) .parent ( push the zero-page position, 1 byte ) ( The memory opcodes are: LDZ STZ LDR STR LDA STA DEI DEO ) ( ---------------------------------------------------------------------------- ) ( Logic allows to create conditionals ) #12 #34 NEQ ,skip JCN #31 EMIT @skip ( Logic also allows to create for-loops ) #3a #30 @loop DUP EMIT ( print "123456789" to console ) INC GTHk ,loop JCN POP2 ( Logic also allows to create while-loops ) ;word @while LDAk EMIT INC2 LDAk ,while JCN POP2 BRK @word "vermillion $1 ( Subroutines can be jumped to with JSR, and returned from with JMP2r ) ;word ,print-word JSR BRK @print-word ( word* -- ) @while LDAk EMIT INC2 LDAk ,while JCN POP2 JMP2r @word "cerulean ( The jump opcodes are: JMP JCN JSR )