A collection of commonly used routines in Uxntal projects.
The following snippets are in the standard format. If you discover faster and smaller helpers, please get in touch with me.
Hexadecimal Numbers
To print an hexadecimal number:
@<phex> ( short* -: ) SWP /b &b ( byte -: ) DUP #04 SFT /c &c ( byte -: ) #0f AND DUP #09 GTH #27 MUL ADD [ LIT "0 ] ADD #18 DEO JMP2r
To convert an hexadecimal string to a value:
@shex ( str* -: val* )
[ LIT2r 0000 ]
&w ( str* `acc* -: val* )
LDAk chex INC #00 EQU ?{
[ LITr 40 ] SFT2r LDAk chex [ LITr 00 ] STH
ADD2r INC2 LDAk ?&w }
POP2 STH2r JMP2r
To convert an hexadecimal character to a nibble:
@chex ( c -: val! )
( dec ) [ LIT "0 ] SUB DUP #09 GTH ?{ JMP2r }
( hex ) #27 SUB DUP #0f GTH ?{ JMP2r }
( err ) POP #ff JMP2r
Decimal Numbers
To print a decimal short to decimal:
@pdec ( short* -- )
#2710 [ LIT2r 00fb ]
&w ( -- )
DIV2k #000a DIV2k MUL2 SUB2 SWPr EQUk OVR STHkr EQU AND ?{
DUP [ LIT "0 ] ADD #19 DEO
INCr }
POP2 #000a DIV2 SWPr INCr STHkr ?&w
POP2r POP2 POP2 JMP2r
To print a decimal byte to decimal:
@print-dec ( dec -- ) DUP #64 DIV print-num/try DUP #0a DIV print-num/try ( >> ) @print-num ( num -- ) #0a DIVk MUL SUB [ LIT "0 ] ADD #18 DEO JMP2r &try ( num -- ) DUP ?print-num POP JMP2r
To convert a decimal string to a hexadecimal value.
@sdec ( str* -- val* ) [ LIT2r 0000 ] &w ( -- ) ( validate ) LDAk [ LIT "0 ] SUB #09 GTH ?&end ( accumulate ) [ LIT2r 000a ] MUL2r ( combine ) LDAk [ LIT "0 ] SUB [ LITr 00 ] STH ADD2r ( continue ) INC2 LDAk ?&w &end POP2 STH2r JMP2r
Strings
To print a string.
@<pstr> ( str* -: ) LDAk #18 DEO INC2 & LDAk ?<pstr> POP2 JMP2r
Helpers for strings:
[TODO]
Memory
To print an entire page of memory:
@pmem ( addr* -- ) #0000 &l ( -- ) ADD2k LDA phex/b DUP #0f AND #0f NEQ #16 MUL #0a ADD #18 DEO INC NEQk ?&l POP2 POP2 JMP2r
Helpers for memory.
[TODO]
Helpers for bitwise operations.
@popcnt ( byte -- count ) LITr 00 #00 &w SFTk #01 AND STH ADDr INC SFTk ?&w POP2 STHr JMP2r
Dates
To find the day of the week from a given date, Tomohiko Sakamoto's method:
@dotw ( y* m d -- dotw ) ( y -= m < 3; ) OVR STH SWP2 #00 STHr #02 LTH SUB2 STH2 ( t[m-1] + d ) #00 ROT ;&t ADD2 LDA #00 SWP ROT #00 SWP ADD2 ( y + y/4 - y/100 + y/400 ) STH2kr STH2kr #02 SFT2 ADD2 STH2kr #0064 DIV2 SUB2 STH2r #0190 DIV2 ADD2 ADD2 ( % 7 ) #0007 DIV2k MUL2 SUB2 NIP JMP2r &t [ 00 03 02 05 00 03 05 01 04 06 02 04 ]
To find if a year is a leap year:
@is-leap-year ( year* -- bool ) ( leap year if perfectly divisible by 400 ) DUP2 #0190 ( MOD2 ) DIV2k MUL2 SUB2 #0000 EQU2 ?&leap ( not a leap year if divisible by 100 ) ( but not divisible by 400 ) DUP2 #0064 ( MOD2 ) DIV2k MUL2 SUB2 #0000 EQU2 ?¬-leap ( leap year if not divisible by 100 ) ( but divisible by 4 ) DUP2 #0003 AND2 #0000 EQU2 ?&leap ( all other years are not leap years ) ¬-leap POP2 #00 JMP2r &leap POP2 #01 JMP2r
Memory
@msfl ( b* a* len* -- ) STH2 SWP2 EQU2k ?&end &l ( -- ) DUP2k STH2kr ADD2 LDA ROT ROT STA INC2 GTH2k ?&l POP2 POP2 &end POP2r JMP2r @msfr ( b* a* len* -- ) STH2 EQU2k ?&end &l ( -- ) DUP2 LDAk ROT ROT STH2kr ADD2 STA #0001 SUB2 LTH2k ?&l POP2 POP2 &end POP2r JMP2r
Random
@prng-init ( -- ) [ LIT2 00 -DateTime/second ] DEI [ LIT2 00 -DateTime/minute ] DEI #60 SFT2 EOR2 [ LIT2 00 -DateTime/hour ] DEI #c0 SFT2 EOR2 ,prng/x STR2 [ LIT2 00 -DateTime/hour ] DEI #04 SFT2 [ LIT2 00 -DateTime/day ] DEI #10 SFT2 EOR2 [ LIT2 00 -DateTime/month ] DEI #60 SFT2 EOR2 .DateTime/year DEI2 #a0 SFT2 EOR2 ,prng/y STR2 JMP2r @prng ( -- number* ) [ LIT2 &x $2 ] DUP2 #50 SFT2 EOR2 DUP2 #03 SFT2 EOR2 [ LIT2 &y $2 ] DUP2 ,&x STR2 DUP2 #01 SFT2 EOR2 EOR2 ,&y STR2k POP JMP2r
Misc
To convert a signed byte to a signed short.
DUP #7f GTH #ff MUL SWP
@smax ( x* y* -> smax* ) EOR2k POP #80 AND ?min !max
@min ( x* y* -> min* ) LTH2k JMP SWP2 POP2 JMP2r
@max ( x* y* -> max* ) LTH2k JMP SWP2 NIP2 JMP2r
@mod ( x y -- z ) DIVk MUL SUB JMP2r
@mod2 ( x* y* -- z* ) DIV2k MUL2 SUB2 JMP2r
( Signed macros )
@abs ( a -- b ) DUP #80 AND #00 EQU ?{ #00 SWP SUB } JMP2r
@abs2 ( a* -- b* ) DUP2k #1f SFT2 MUL2 SUB2 JMP2r
@lts2 ( a* b* -- f ) #8000 STH2k ADD2 SWP2 STH2r ADD2 GTH2 JMP2r
@gts2 ( a* b* -- f ) #8000 STH2k ADD2 SWP2 STH2r ADD2 LTH2 JMP2r
( Binary macros )
@rol ( x y -- z ) DUP #07 SFT SWP #10 SFT ADD JMP2r
@ror ( x y -- z ) DUP #70 SFT SWP #01 SFT ADD JMP2r
@rol2 ( x* y* -- z* ) DUP2 #0f SFT2 SWP2 #10 SFT2 ADD2 JMP2r
@ror2 ( x* y* -- z* ) DUP2 #f0 SFT2 SWP2 #01 SFT2 ADD2 JMP2r
I have reordered time. I have turned the world upside down, and I have done it all for you!
Self-Generating
The following program will emit its own bytecode when run:
( uxncli gen.rom > gen-self.rom ) @q ;&end ;q &l LDAk #18 DEO INC2 GTH2k ?&l &end
The program above compiles to the resulting emitted bytecode:
a001 0fa0 0100 9480 1817 21aa 20ff f7
Self-Printing
The following program will emit a program that emits its own bytecode as hexadecimal ascii characters:
( uxncli pri.rom ) @q ;end ;q &l LDA2k phex #2018 DEO INC2 INC2 GTH2k ?&l BRK @phex ( short* -- ) SWP phex/b &b DUP #04 SFT phex/c &c #0f AND DUP #09 GTH #27 MUL ADD [ LIT "0 ] ADD #18 DEO JMP2r @end
Running the previous program generates the following hexadecimal values which are also valid source code:
a001 32a0 0100 b460 000b a020 1817 2121 aa20 fff2 0004 6000 0006 8004 1f60 0000 800f 1c06 8009 0a80 271a 1880 3018 8018 176c
Maze
A small program to print the iconic Commodore 64 maze:
@maze ( -> ) ( seed ) #c5 DEI2 ,&seed STR2 &w ( -- ) [ LIT2 "/\ ] [ LIT2 &seed &x $1 &y $1 ] ( rand x ) ADDk #50 SFT EOR DUP #03 SFT EOR DUP ,&x STR ( rand y ) SUBk #01 SFT EOR EOR DUP ,&y STR ( emit ) #01 AND [ JMP SWP POP ] #18 DEO !&w
Where Are We?
From anywhere during a program's execution, the location of the program counter can be pushed onto the working stack with the following snippet:
[ LITr 00 ] JSRr
