Days

1. Day 7 :: Hello UXN!

Day 7

Ok, ready to start decadv2025 in earnest

First, a utility:

# ~/.aliases
function uxnrun() {
  local tal="$1"
  local rom="${tal%.tal}.rom"
  exists-f "$tal" || return 1;
  uxnasm "$tal" "$rom" && uxnemu "$rom"
}

function uxndbg() {
  local tal="$1"
  local rom="${tal%.tal}.rom"
  exists-f "$tal" || return 1;
  uxnasm "$tal" "$rom" && uxnemu -2x ~/roms/beetbug.rom "$rom"
}

I was looking at an example of printing date-times and noticed there was some kind of implicit syntax with subroutine labels, so I read man 7 uxntal:

 JCI, JMI, and JSI
     The "immediate jump" instructions are produced by the  assembler.  They  interpret  the
     next 2 bytes of the ROM as a relative address (addr) and have the following effects:

      JMI ( -- )       jump to addr unconditionally
      JCI ( bool^ -- ) jump to addr if bool is non-zero
      JSI ( -- [pc*] ) jump to addr saving the current address (pc) on rst

     (The instruction pointer will be moved forward 2 bytes, past the relative address.)

     These instructions are created by the assembler from special syntax:

         !dest produces JMI wx yz
         ?dest produces JCI wx yz
         dest  produces JSI wx yz (assuming dest is not a macro or reserved)

so, that makes sense of this kind of tal incantation:

|0100
  #09 <emit-decimal>
  #05 <emit-decimal>
  BRK

@<emit-decimal> ( byte -- )
  LIT "0 ADD #18 DEO
  JMP2r

::14:48::

It's a little primitive, but I've made an isodate emitter in uxn:

|10 @Console &vector $2 &read $1 &pad $4 &type $1 &write $1 &error $1
|c0 @Datetime &year $2 &month $1 &day $1 &hour $1 &minute $1 &second $1 &dotw $1 &doty $2 &isdst $1

|0100
  @on-reset
  .Datetime/year DEI2 \print-4digit
  LIT "- .Console/write DEO
  .Datetime/month DEI \print-2digit
  LIT "- .Console/write DEO
  .Datetime/day DEI \print-2digit
  LIT "/ .Console/write DEO
  .Datetime/hour DEI \print-2digit
  LIT ": .Console/write DEO
  .Datetime/minute DEI \print-2digit
  LIT ": .Console/write DEO
  .Datetime/second DEI \print-2digit
  BRK

@\emit-decimal ( byte -- )
  LIT "0 ADD #18 DEO
  JMP2r

@\print-2digit ( 2-digit -- )
  #0a DIVk \emit-decimal
  DIVk MUL SUB
  \emit-decimal
  JMP2r

@\print-4digit ( 4-digit* -- )
  #03e8 DIVk2 \emit-decimal POP ( 1000s )
  DIVk2 MUL2 SUB2
  #0064 DIVk2 \emit-decimal POP ( 100s )
  DIVk2 MUL2 SUB2
  #0a DIVk \emit-decimal ( 10s )
  DIVk MUL SUB
  \emit-decimal ( 1s )
  JMP2r

( uxncli datetime.rom -- 2025-11-07/15:13:48 )

At this point I could either extend it logically by having it emit something like "Sunday, December 7th", or I could extend it by making it a graphical application -- a little desktop clock.

I'm partial to figuring out fonts and animation.