• Url

  https://compudanzas.net/uxn_tutorial_day_1.html

• Explains the basic concepts of the UXN CPU

• CPU

• Can handle words of 1 or two bytes

• Each instruction is encoded in 1 byte

• 32 possible instructions + 3 mode flags

• Memory

• Four separate spaces

• main memory

  64 Kibibytes

• First 256 bytes are "zero page", which can be accessed with 1 byte

• Stores the program to be executed, starting at

  0x0100

• i/o memory

  256 bytes divided in 16 sections/devices of 16bytes each

• working stack

  256 bytes

• cannot be accessed randomly

• return stack

  256 bytes

• cannot be accessed randomly

• Writes, runs and goes step-by-step describing a "hello-world" program.

• Explains [ UXNtal ] concepts

• Runes

runes are special characters that indicate to uxnasm some pre-processing to do when assembling our programs.

• Absolute pad

  |

• Pads up elements until a memory position is reached

• Literal hex

  #

• Rewrites #AA to LIT AA

• Raw character

  '

• Rewrites 'h to 68 (note that in this case LIT may be necessary)

• Labels

  @ and & to define, . and / to use

• Can be used to define something like struct-offset macros (difficult to explain in few words).

• Macros

  %<NAME> to define, just "<name>" to invoke

• Shows screen usage

• Pixel drawing

• Sprite drawing

• Runes

• Literal absolute

  ;

• Push the address of a @ label to the stack

• Presents

• the @Controller device

• Used to receive keyboard (and game controller) events

• Arrow keys and Ctrl are handled by using the .Controller/button register

• control flow mechanisms

• bitwise logic

• stack manipulation

• runes for addresses

• .label

  literal address in zero page

• ;label

  literal address in main memory

• ,label

  literal relative address in main memory

• :label

  main addres in main memory

• @label

  Label definition

• &sublabel

  Definition of a sublabel

• Refer to it as label/sublabel

• Or just &sublabel for local sublabels