collapseos/362 at 7cad9ffe4086fd413346390df4e25174ad760076 - collapseos - SKS Gitea

izaya/collapseos

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Virgil Dupras 2d17b4e8ec Make string length-prefixed instead of null-terminated

I'm not sure why I chose null-terminated initially. Probably because
the z80asm version had null-terminated strings.

Length-prefixes strings are the traditional form of strings in Forth
and it's a bit easier to work with them with traditional forth words
when they're under this form.

2020-05-25 20:34:52 -04:00

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 : (parseb)          ( a -- n f )
     ( '0': ASCII 0x30 'b': 0x62 0x6230 )
     DUP 1+ @ 0x6230 = NOT IF 0 EXIT THEN ( a 0 )
     ( We have "0b" prefix )
     DUP C@ ( a len )
 SWAP 1+ ( len+1 ) 3 DO ( a r )
         OVER I + C@ ( a r c ) _ ( a r n )
         DUP 0< IF 2DROP 0 UNLOOP EXIT THEN
         SWAP 1 LSHIFT + ( a r*2+n ) LOOP
     NIP 1 ;