/
subleq.fth
3169 lines (3167 loc) · 117 KB
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subleq.fth
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defined eforth [if] ' ) <ok> ! [then] ( Turn off ok prompt )
\ Project: Cross Compiler / eForth interpreter for a SUBLEQ CPU
\ License: The Unlicense
\ Author: Richard James Howe
\ Email: howe.r.j.89@gmail.com
\ Repo: <https://github.com/howerj/subleq>
\
\ References:
\
\ - <https://en.wikipedia.org/wiki/Threaded_code>
\ - <https://github.com/howerj/embed>
\ - <https://github.com/howerj/forth-cpu>
\ - <https://github.com/samawati/j1eforth>
\ - <https://www.bradrodriguez.com/papers/>
\ - 8086 eForth 1.0 by Bill Muench and C. H. Ting, 1990
\ - <https://www.bradrodriguez.com/papers/mtasking.html>,
\ For multitasking support
\ - <https://forth-standard.org/standard/block>,
\ For the block word-set, which is partially implemented.
\ - The optional Forth floating point code is derived from
\ code found in Vierte Dimensions, Vol.2, No.4, 1986. It has
\ a liberal license, so long as the following copyright is
\ still attached:
\
\ FORTH-83 FLOATING POINT.
\ ----------------------------------
\ COPYRIGHT 1985 BY ROBERT F. ILLYES
\
\ PO BOX 2516, STA. A
\ CHAMPAIGN, IL 61820
\ PHONE: 217/826-2734
\
\ The way this cross compiler works is the following:
\
\ 1. An assembler for the SUBLEQ machine is made.
\ 2. A virtual machine is made with that assembler that can
\ support higher level programming constructs, specifically,
\ the easy execution of Forth.
\ 3. Forth word definitions are built up, which are then used
\ to construct a full Forth interpreter.
\ 4. The resulting image is output to standard out.
\
\ Check the references for more detailed examples for other
\ systems. Some keywords that will help are; Forth,
\ Meta-compilation, Cross compiler, eForth, 8086 eForth,
\ JonesForth, j1eforth.
\
\ Notes:
\
\ - If "see", the decompiler, was advanced enough we could
\ dispense with the source code, an interesting concept.
\ - The eForth image could determine the SUBLEQ machine size,
\ and adjust itself accordingly, it would not even require a
\ power-of-two integer width. Another interesting concept would
\ be to adapt this eForth to a SUBLEQ machine that used bignums
\ for each cell, this would require re-engineering functions
\ like bitwise AND/OR/XOR as they require a fixed cell width to
\ work efficiently.
\ - The eForth image could be compressed with LZSS to save on
\ space. If the de-compressor was written in pure SUBLEQ it
\ would compression of most of the image instead of just the
\ eForth section of it.
\ - A website with an interactive simulator is available at:
\ <https://github.com/howerj/subleq-js>
\ - It would be nice to make a 7400 Integrated Circuit board
\ that could run and execute this code, or a project in VHDL
\ for an FPGA that could do it.
\ - The virtual machine could be sped up with optimization
\ magic
\ - Half of the memory used is just for the virtual machine
\ that allows Forth to be written.
\ - The BLOCK word-set does not use mass storage, but maps
\ blocks to memory, if a mass storage peripheral were to be
\ added these functions would have to be modified. It might be
\ nice to make a Forth File System based on blocks as well,
\ then this system could act like a primitive DOS.
\ - Reformatting the text for a 64 byte line width would allow
\ storage in Forth blocks. This file could then perhaps we
\ stored within the image.
\ - Much like my Embed VM project and Forth interpreter,
\ available at \ <https://github.com/howerj/embed>, this file
\ could be documented extensively and explain how to build up
\ a Forth interpreter from scratch.
\
only forth definitions hex
1 constant opt.multi ( Add in large "pause" primitive )
1 constant opt.editor ( Add in Text Editor )
1 constant opt.info ( Add info printing function )
0 constant opt.generate-c ( Generate C code )
0 constant opt.better-see ( Replace 'see' with better version )
0 constant opt.control ( Add in more control structures )
0 constant opt.allocate ( Add in "allocate"/"free" )
0 constant opt.float ( Add in floating point code )
0 constant opt.glossary ( Add in "glossary" word )
0 constant opt.sm-vm-err ( Smaller VM error message )
0 constant opt.optimize ( Enable extra optimization )
1 constant opt.divmod ( Use "opDivMod" primitive )
1 constant opt.self ( Enable self-interpreter )
: sys.echo-off 1 or ; ( bit #1 = turn echoing chars off )
: sys.cksum 2 or ; ( bit #2 = turn checksumming on )
: sys.info 4 or ; ( bit #3 = print info msg on startup )
: sys.eof 8 or ; ( bit #4 = die if received EOF )
: sys.warnv $10 or ; ( bit #5 = warn if virtualized )
0 ( sys.cksum ) sys.eof sys.echo-off sys.warnv constant opt.sys
defined (order) 0= [if]
: (order) ( w wid*n n -- wid*n w n )
dup if
1- swap >r recurse over r@ xor
if 1+ r> -rot exit then rdrop
then ;
: -order get-order (order) nip set-order ; ( wid -- )
: +order dup >r -order get-order r> swap 1+ set-order ;
[then]
defined [unless] 0= [if]
: [unless] 0= postpone [if] ; immediate
[then]
defined eforth [if]
: wordlist here cell allot 0 over ! ; ( -- wid : alloc wid )
[then]
wordlist constant meta.1 ( meta-compiler word set )
wordlist constant target.1 ( target eForth word set )
wordlist constant assembler.1 ( assembler word set )
wordlist constant target.only.1 ( target only word set )
defined eforth [if] system +order [then]
meta.1 +order definitions
2 constant =cell \ Target cell size
4000 constant size \ Size of image working area
100 constant =buf \ Size of text input buffers in target
100 constant =stksz \ Size of return and variable stacks
FC00 constant =thread \ Initial start of thread area
0008 constant =bksp \ Backspace character value
000A constant =lf \ Line feed character value
000D constant =cr \ Carriage Return character value
007F constant =del \ Delete character
create tflash tflash size cells allot size erase
variable tzreg 0 tzreg !
variable tareg 1 tareg !
variable tdp 0 tdp ! ( target dictionary pointer )
variable tlast 0 tlast ! ( last defined target word pointer )
variable tlocal 0 tlocal ! ( local variable allocator )
variable voc-last 0 voc-last ! ( last defined in any vocab )
: :m meta.1 +order definitions : ; ( --, "name" )
: ;m postpone ; ; immediate ( -- )
:m tcell 2 ;m ( -- 2 : bytes in a target cell )
:m there tdp @ ;m ( -- a : target dictionary pointer value )
:m tc! tflash + c! ;m ( c a -- : target write char )
:m tc@ tflash + c@ ;m ( a -- c : target get char )
:m t! over FF and over tc! swap 8 rshift swap 1+ tc! ;m
:m t@ dup tc@ swap 1+ tc@ 8 lshift or ;m ( a -- u : target @ )
:m taligned dup 1 and + ;m ( u -- u : align target pointer )
:m talign there 1 and tdp +! ;m ( -- : align target dic. ptr. )
:m tc, there tc! 1 tdp +! ;m ( c -- : write char to targ. dic.)
:m t, there t! 2 tdp +! ;m ( u -- : write cell to target dic. )
:m tallot tdp +! ;m ( u -- : allocate bytes in target dic. )
:m mdrop drop ;m ( u -- : always call drop )
:m mswap swap ;m ( u -- : always call swap )
:m mdecimal decimal ;m ( -- : always call decimal )
:m mhex hex ;m ( -- : always call hex )
defined eforth [if]
:m tpack dup tc, for aft count tc, then next drop ;m
:m parse-word bl word ?nul count ;m ( -- a u )
:m limit ;m ( u -- u16 : not needed on 16-bit systems )
[else]
:m tpack talign dup tc, 0 ?do count tc, loop drop ;m
:m limit FFFF and ;m ( u -- u16 : limit variable to 16 bits )
[then]
:m $literal talign [char] " word count tpack talign ;m
defined eforth [if]
:m #dec s>d if [char] - emit then (.) ;m ( n16 -- )
[else]
:m #dec dup 8000 u>= if negate limit -1 >r else 0 >r then
0 <# #s r> sign #> type ;m ( n16 -- )
[then]
opt.generate-c [if]
:m msep 2C emit ;m ( -- : emit "," as separator )
[else]
:m msep A emit ;m ( -- : emit space as separator )
[then]
:m mdump taligned ( a u -- )
begin ?dup
while swap dup @ limit #dec msep tcell + swap tcell -
repeat drop ;m
:m save-target decimal tflash there mdump ;m ( -- )
:m .end only forth definitions decimal ;m ( -- )
:m atlast tlast @ ;m ( -- a : meta-comp last defined word )
:m local? tlocal @ ;m ( -- u : meta-comp local offset )
:m lallot >r tlocal @ r> + tlocal ! ;m ( u -- allot in target )
:m tuser ( --, "name", Created-Word: -- u )
get-current >r meta.1 set-current create r>
set-current tlocal @ =cell lallot , does> @ ;m
:m tvar get-current >r ( --, "name", Created-Word: -- a )
meta.1 set-current create
r> set-current there , t, does> @ ;m
:m label: get-current >r ( --, "name", Created-Word: -- a )
meta.1 set-current create
r> set-current there , does> @ ;m
:m tdown =cell negate and ;m ( a -- a : align down )
:m tnfa =cell + ;m ( pwd -- nfa : move to name field address )
:m tcfa tnfa dup c@ 1F and + =cell + tdown ;m ( pwd -- cfa )
:m compile-only voc-last @ tnfa t@ 20 or voc-last @ tnfa t! ;m
:m immediate voc-last @ tnfa t@ 40 or voc-last @ tnfa t! ;m
:m half dup 1 and abort" unaligned" 2/ ;m ( a -- a : meta 2/ )
:m double 2* ;m ( a -- a : meta-comp 2* )
defined eforth [if]
:m (') bl word find ?found cfa ;m
:m t' (') >body @ ;m ( --, "name" )
:m to' target.only.1 +order (') >body @ target.only.1 -order ;m
[else]
:m t' ' >body @ ;m ( --, "name" )
:m to' target.only.1 +order ' >body @ target.only.1 -order ;m
[then]
:m tcompile to' half t, ;m
:m >tbody =cell + ;m
:m tcksum taligned dup C0DE - FFFF and >r
begin ?dup
while swap dup t@ r> + FFFF and >r =cell + swap =cell -
repeat drop r> ;m ( a u -- u : compute a checksum )
:m mkck dup there swap - tcksum ;m ( -- u : checksum of image )
:m postpone ( --, "name" )
target.only.1 +order t' target.only.1 -order 2/ t, ;m
:m thead talign there tlast @ t, dup tlast ! voc-last !
parse-word talign tpack talign ;m ( --, "name" )
:m header >in @ thead >in ! ;m ( --, "name" )
:m :ht ( "name" -- : forth routine, no header )
get-current >r target.1 set-current create
r> set-current CAFE talign there ,
does> @ 2/ t, ;m
:m :t header :ht ;m ( "name" -- : forth routine )
:m :to ( "name" -- : forth, target only routine )
header
get-current >r
target.only.1 set-current create
r> set-current
CAFE talign there ,
does> @ 2/ t, ;m
:m :a ( "name" -- : assembly routine, no header )
1234 target.1 +order definitions
create talign there , assembler.1 +order does> @ 2/ t, ;m
:m (fall-through); 1234 <>
if abort" unstructured" then assembler.1 -order ;m
:m (a); (fall-through); ;m
defined eforth [if] system -order [then]
:m Z tzreg @ t, ;m ( -- : Address 0 must contain 0 )
:m A, Z ;m ( -- : Synonym for 'Z', temporary location )
:m V, tareg @ t, ;m ( -- : Address 1 also contains 0, tmp loc )
:m NADDR there 2/ 1+ t, ;m ( --, jump to next cell )
:m HALT Z Z -1 t, ;m ( --, Halt but do not catch fire )
:m JMP 2/ Z Z t, ;m ( a --, Jump to location )
:m ADD swap 2/ t, Z NADDR Z 2/ t, NADDR Z Z NADDR ;m
:m SUB swap 2/ t, 2/ t, NADDR ;m ( a a -- : subtract )
:m NOOP Z Z NADDR ;m ( -- : No operation )
:m ZERO dup 2/ t, 2/ t, NADDR ;m ( a -- : zero a location )
:m PUT 2/ t, -1 t, NADDR ;m ( a -- : put a byte )
:m GET 2/ -1 t, t, NADDR ;m ( a -- : get a byte )
:m MOV 2/ >r r@ dup t, t, NADDR 2/ t, Z NADDR r> Z t, NADDR
Z Z NADDR ;m
:m iJMP there 2/ E + 2* MOV Z Z NADDR ;m ( a -- )
:m iADD ( a a -- : indirect add )
2/ t, A, NADDR
2/ t, V, NADDR
there 2/ 7 + dup dup t, t, NADDR
A, t, NADDR
V, 0 t, NADDR
A, A, NADDR
V, V, NADDR ;m
:m iSUB ( a a -- : indirect sub )
2/ t, A, NADDR
2/ >r
there 2/ 7 + dup dup t, t, NADDR
A, t, NADDR
r> t, 0 t, NADDR
A, A, NADDR ;m
:m iSTORE ( a a -- : Indirect Store )
2/ t, A, NADDR
there 2/ 3 4 * + dup t, t, NADDR
there 2/ $A + dup t, t, NADDR
A, there 2/ 5 + t, NADDR
A, there 2/ 3 + t, NADDR
0 t, 0 t, NADDR
2/ t, V, NADDR
there 2/ 7 + dup dup t, t, NADDR
A, t, NADDR
V, 0 t, NADDR
A, A, NADDR
V, V, NADDR
;m
:m iLOAD there 2/ 3 4 * 3 + + 2* MOV 0 swap MOV ;m ( a a -- )
assembler.1 +order definitions
: begin talign there ; ( -- a )
: again JMP ; ( a -- )
: mark there 0 t, ; ( -- a : create hole in dictionary )
: if talign ( a -- a : NB. "if" does not work for $8000 )
2/ dup t, Z there 2/ 4 + dup t, Z Z 6 + t, Z Z NADDR Z t,
mark ;
: until 2/ dup t, Z there 2/ 4 + dup t, Z Z 6 + t,
Z Z NADDR Z t, 2/ t, ; ( a -- a )
: else talign Z Z mark swap there 2/ swap t! ; ( a -- a )
: +if talign Z 2/ t, mark ; ( a -- a )
: -if talign
2/ t, Z there 2/ 4 + t, Z Z there 2/ 4 + t, Z Z mark ;
: then begin 2/ swap t! ; ( a -- )
: while if swap ; ( a a -- a a )
: repeat JMP then ; ( a a -- )
assembler.1 -order
meta.1 +order definitions
0 t, 0 t, \ both locations must be zero
label: entry \ used to set entry point in next cell
-1 t, \ system entry point, set later
opt.sys tvar {options} \ bit #1=echo off, #2 = checksum on,
\ #4=info, #8=die on EOF
0 tvar primitive \ any address lower must be a VM primitive
=stksz half tvar stacksz \ must contain $80
-1 tvar neg1 \ must contain -1
1 tvar one \ must contain 1
$10 tvar bwidth \ must contain 16
$40 tvar mwidth \ maximum machine width
0 tvar r0 \ working pointer 1 (register r0)
0 tvar r1 \ register 1
0 tvar r2 \ register 2
0 tvar r3 \ register 3
0 tvar r4 \ register 4
opt.self [if]
0 tvar {virtual} \ are we virtualized?
0 tvar {self} \ location of the self interpreter
0 tvar {pc} \ Emulated SUBLEQ Machine program counter
$10 tvar {width} \ set by size detection routines
[then]
0 tvar h \ dictionary pointer
=thread half tvar {up} \ Current task addr. (Half size)
0 tvar check \ used for system checksum
0 tvar {context} E tallot \ vocabulary context
0 tvar {current} \ vocabulary to add new definitions to
0 tvar {forth-wordlist} \ forth word list (main vocabulary)
0 tvar {editor} \ editor vocabulary
0 tvar {root-voc} \ absolute minimum vocabulary
0 tvar {system} \ system functions vocabulary
0 tvar {cold} \ entry point of VM program, set later on
0 tvar {last} \ last defined word
0 tvar {cycles} \ number of times we have switched tasks
1 tvar {single} \ is multi processing off? +ve = off
0 tvar {user} \ Number of locals assigned
\ Thread variables, not all of which are user variables
0 tvar ip \ instruction pointer
0 tvar tos \ top of stack
=thread =stksz + half dup tvar {rp0} tvar {rp}
=thread =stksz double + half dup tvar {sp0} tvar {sp}
200 constant =tib \ Start of terminal input buffer
380 constant =num \ Start of numeric input buffer
tuser {next-task} \ next task in task list
tuser {ip-save} \ saved instruction pointer
tuser {tos-save} \ saved top of variable stack
tuser {rp-save} \ saved return stack pointer
tuser {sp-save} \ saved variable stack pointer
tuser {handler} \ throw/catch handler
tuser {sender} \ multitasking; msg. send, 0 = no message
tuser {message} \ multitasking; the message itself
tuser {id} \ executing from block or terminal?
tuser {precision} \ floating point precision (if FP on)
:m INC 2/ neg1 2/ t, t, NADDR ;m ( b -- )
:m DEC 2/ one 2/ t, t, NADDR ;m ( b -- )
:m ONE! dup ZERO INC ; ( a -- : set address to '1' )
:m NG1! dup ZERO DEC ; ( a -- : set address to '-1' )
:m ++sp {sp} DEC ;m ( -- : grow variable stack )
:m --sp {sp} INC ;m ( -- : shrink variable stack )
:m --rp {rp} DEC ;m ( -- : shrink return stack )
:m ++rp {rp} INC ;m ( -- : grow return stack )
opt.optimize [if] ( optimizations on )
:m a-optim 2/ >r there =cell - r> swap t! ;m ( a -- )
[else]
:m a-optim drop ;m ( a -- : optimization off )
[then]
opt.sm-vm-err [if]
( Smaller, more cryptic, error message string "Error" )
45 tvar err-str
72 t, 72 t, 6F t, 72 t, 0D t, 0A t, -1 t,
[else]
( Error message string "Error: Not a 16-bit SUBLEQ VM" )
45 tvar err-str
72 t, 72 t, 6F t, 72 t, 3A t, 20 t, 4E t,
6F t, 74 t, 20 t, 61 t, 20 t, 31 t, 36 t, 2D t,
62 t, 69 t, 74 t, 20 t, 53 t, 55 t, 42 t, 4C t,
45 t, 51 t, 20 t, 56 t, 4D t, 0D t, 0A t, -1 t,
[then]
err-str 2/ tvar err-str-addr
assembler.1 +order
label: die
err-str-addr r0 MOV ( load string address )
label: die.loop
r1 r0 iLOAD ( load character )
r0 INC ( increment to next cell )
r1 +if
r1 PUT ( output single byte )
die.loop JMP ( sentinel is a negative val )
then
( fall-through )
:a bye ( -- : first VM word, "bye", or halt the Forth system )
HALT (a); ( ...like tears in rain. Time to die. )
assembler.1 +order
label: start \ System Entry Point
start 2/ entry t! \ Set the system entry point
r0 ONE! \ r0 = shift bit loop count
r1 ONE! \ r1 = number of bits
label: chk16
r0 r0 ADD \ r0 = r0 * 2
r1 INC \ r1++
r1 r2 MOV \ r2 = r1
mwidth r2 SUB r2 +if die JMP then \ check length < max width
r0 +if chk16 JMP then \ check if still positive
opt.self [if] \ if width > 16, jump to 16-bit emulator
r1 r2 MOV
r1 {width} MOV \ Save actual machine width
bwidth r2 SUB r2 +if {self} iJMP then
[then]
bwidth r1 SUB r1 if die JMP then \ r1 - bwidth should be 0
opt.self [if] ( self JMP ) there 2/ {pc} t! [then]
{sp0} {sp} MOV \ Setup initial variable stack
{rp0} {rp} MOV \ Setup initial return stack
{cold} ip MOV \ Get the first instruction to execute
( fall-through )
label: vm ( Forth Inner Interpreter )
r0 ip iLOAD \ Get instruction to execute from IP
ip INC \ IP now points to next instruction!
primitive r1 MOV \ Copy as SUB is destructive
r0 r1 SUB \ Check if it is a primitive
r1 +if r0 iJMP then \ Jump straight to VM functions if it is
++rp \ If it wasn't a VM instruction, inc {rp}
ip {rp} iSTORE \ and store ip to return stack
r0 ip MOV vm a-optim \ "r0" holds our next instruction
vm JMP \ Ad infinitum...
:m ;a (fall-through); vm a-optim vm JMP ;m
opt.self [if]
0 tvar {zreg} {zreg} 2/ tzreg !
0 tvar {areg} {areg} 2/ tareg !
0000 tvar {a} ( Emulated 'a' operand )
0000 tvar {b} ( Emulated 'b' operand )
0000 tvar {v} ( Temporary register 'v' )
-0010 tvar {count} ( Top bit count, modified later )
label: self
self 2/ {self} t!
{virtual} NG1!
{width} {count} ADD
label: self-loop
{pc} {v} MOV \ Copy {pc} for next instruction
neg1 2/ t, {v} 2/ t, -1 t, \ Conditionally halt on '{c}'
{a} {pc} iLOAD {pc} INC
{b} {pc} iLOAD {pc} INC
{a} {v} MOV {v} INC {v} +if ( Input byte? )
{b} {v} MOV {v} INC {v} +if ( Output byte? )
( Neither Input nor Output, must be normal instruction )
\ This section performs "m[b] = m[b] - m[a]" and loads
\ the result back into "{a}". A custom "iSUB" routine
\ might speed things up here, one that stored the result
\ in "{b}" but also kept a copy in "{a}".
{a} {a} iLOAD \ a = m[a]
{a} {b} iSUB \ m[b] = m[b] - a
{a} {b} iLOAD \ a = m[b]
\ This section prepares "{a}" for the next "+if", it
\ shifts the 16-bit into the top place depending on the
\ machine width. The bits lower than the 16-bit do not
\ matter unless they are all zero, in which case this
\ shifting has no effect anyway.
{count} {v} MOV
label: self.bit
{a} {a} ADD {v} DEC
{v} +if self.bit JMP then
{a} +if \ !(v == 0 || v & 0x8000)
{pc} INC
self-loop JMP
then
{pc} {pc} iLOAD \ pc = m[c]
self-loop JMP
then ( Output byte from m[a] )
{a} {a} iLOAD
{a} PUT
{pc} INC
self-loop JMP
then ( Input byte and store in m[b] )
{a} GET
{a} {b} iSTORE
{pc} INC
self-loop JMP ( And do it again... )
0 tzreg !
1 tareg !
[then]
assembler.1 -order
:a opSwap tos r0 MOV tos {sp} iLOAD r0 {sp} iSTORE ;a
:a opDup ++sp tos {sp} iSTORE ;a ( n -- n n )
:a opFromR ++sp tos {sp} iSTORE tos {rp} iLOAD --rp ;a
:a opToR ++rp tos {rp} iSTORE (fall-through); ( !!! )
:a opDrop tos {sp} iLOAD --sp ;a ( n -- )
:a [@] tos tos iLOAD ;a ( a -- a : load SUBLEQ address )
:a [!] r0 {sp} iLOAD r0 tos iSTORE --sp t' opDrop JMP (a);
:a opEmit tos PUT t' opDrop JMP (a); ( n -- )
:a opExit ip {rp} iLOAD (fall-through); ( !!! ) ( R: a -- )
:a rdrop --rp ;a ( R: u -- )
:a opIpInc ip INC ;a ( -- : increment instruction pointer )
:a opJumpZ ( u -- : Conditional jump on zero )
tos r0 MOV
tos {sp} iLOAD --sp
r0 if t' opIpInc JMP then r0 DEC r0 +if t' opIpInc JMP then
(fall-through); ( !!! )
:a opJump ip ip iLOAD ;a ( -- : Unconditional jump )
:a opNext r0 {rp} iLOAD ( R: n -- | n-1 )
r0 +if r0 DEC r0 {rp} iSTORE t' opJump JMP then
--rp t' opIpInc JMP (a);
:a op0= ( n -- f : not equal to zero )
( does not work: "tos if tos ZERO else tos NG1! then vm JMP" )
tos if ( assembly 'if' does not work for entire range )
tos ZERO
else ( deal with incorrect results )
tos DEC
tos +if tos ZERO else tos NG1! then
then ;a
:a leq0 ( n -- 0|1 : less than or equal to zero )
Z tos 2/ t, there 2/ 4 + t,
tos 2/ dup t, t, vm 2/ t,
tos ONE! ;a
:a - tos {sp} iSUB t' opDrop JMP (a); ( n n -- n )
:a + tos {sp} iADD t' opDrop JMP (a); ( n n -- n )
:a shift ( u n -- u : right shift 'u' by 'n' places )
bwidth r0 MOV \ load machine bit width
tos r0 SUB \ adjust tos by machine width
tos {sp} iLOAD --sp \ pop value to shift
r1 ZERO \ zero result register
label: shift.loop
r1 r1 ADD \ double r1, equivalent to left shift by one
\ work out what bit to shift into r1
tos +if else
tos r2 MOV r2 INC r2 +if else r1 INC then then
tos tos ADD \ double tos, equivalent to left shift by one
r0 DEC \ decrement loop counter
r0 +if shift.loop JMP then
r1 tos MOV ;a \ move result back into tos
:a opMux ( u1 u2 u3 -- u : bitwise multiplexor function )
\ tos contains multiplexor value
bwidth r0 MOV \ load loop counter initial value [16]
r1 ZERO \ zero results register
r3 {sp} iLOAD --sp \ pop first input
r4 {sp} iLOAD --sp \ pop second input
label: opMux.loop
r1 r1 ADD \ shift results register
\ determine topmost bit of 'tos', place result in 'r2'
\ this is used to select whether to use r3 or r4
tos +if label: opMux.r3 r3 r2 MOV else
tos r2 MOV
r2 INC r2 +if
opMux.r3 JMP ( space saving ) else
r4 r2 MOV then then
\ determine whether we should add 0/1 into result
r2 +if else r2 INC r2 +if else r1 INC then then
tos tos ADD \ shift tos
r3 r3 ADD \ shift r3
r4 r4 ADD \ shift r4
r0 DEC \ decrement loop counter
r0 +if opMux.loop JMP then
r1 tos MOV ;a \ move r1 to tos, returning our result
opt.divmod [if]
:a opDivMod ( u1 u2 -- u1 u2 )
r0 {sp} iLOAD
r1 ZERO ( zero quotient )
label: divStep
r1 INC ( increment quotient )
tos r0 SUB ( repeated subtraction )
r0 -if
tos r0 ADD ( correct remainder )
r1 DEC ( correct quotient )
r1 tos MOV ( store results back to tos )
r0 {sp} iSTORE ( ...and stack )
vm JMP ( finish... )
then
divStep JMP ( perform another division step )
(a);
[then]
opt.multi [if]
:a pause ( -- : pause and switch task )
\ "{single}" must be positive and not zero to
\ turn off "pause", this is to save space as "+if" can be
\ used.
{single} +if vm JMP then \ Do nothing if single-threaded mode
r0 {up} iLOAD \ load next task pointer from user storage
\ "+if" saves space, "r0" should never be negative anyway as
\ this would mean that the thread was above the 32678 mark
\ and thus in an area where "@" and "!" would not work (only
\ "[@]" and "[!]".
r0 +if
{cycles} INC \ increment "pause" count
{up} r1 MOV r1 INC \ load TASK pointer, skip next task loc
ip r1 iSTORE r1 INC \ save registers to current task
tos r1 iSTORE r1 INC \ only a few need to be saved
{rp} r1 iSTORE r1 INC
{sp} r1 iSTORE
r0 {rp0} MOV stacksz {rp0} ADD \ change {rp0} to new loc
{rp0} {sp0} MOV stacksz {sp0} ADD \ same but for {sp0}
r0 {up} MOV r0 INC \ set next task
ip r0 iLOAD r0 INC \ reverse of save registers
tos r0 iLOAD r0 INC
{rp} r0 iLOAD r0 INC
{sp} r0 iLOAD \ we're all golden
then ;a
[else]
:m pause ;m ( -- [disabled] )
[then]
there 2/ primitive t! ( set 'primitive', needed for VM )
:m munorder target.only.1 -order talign ;m
:m (;t)
CAFE <> if abort" Unstructured" then
munorder ;m
:m ;t (;t) opExit ;m
:m :s tlast @ {system} t@ tlast ! F00D :t drop 0 ;m
:m :so tlast @ {system} t@ tlast ! F00D :to drop 0 ;m
:m ;s drop CAFE ;t F00D <> if abort" unstructured" then
tlast @ {system} t! tlast ! ;m
:m :r tlast @ {root-voc} t@ tlast ! BEEF :t drop 0 ;m
:m ;r drop CAFE ;t BEEF <> if abort" unstructured" then
tlast @ {root-voc} t! tlast ! ;m
:m :e tlast @ {editor} t@ tlast ! DEAD :t drop 0 ;m
:m ;e drop CAFE ;t DEAD <> if abort" unstructured" then
tlast @ {editor} t! tlast ! ;m
:m system[ tlast @ {system} t@ tlast ! BABE ;m
:m ]system BABE <> if abort" unstructured" then
tlast @ {system} t! tlast ! ;m
:m root[ tlast @ {root-voc} t@ tlast ! D00D ;m
:m ]root D00D <> if abort" unstructured" then
tlast @ {root-voc} t! tlast ! ;m
:m : :t ;m ( -- ???, "name" : start cross-compilation )
:m ; ;t ;m ( ??? -- : end cross-compilation of a target word )
:m begin talign there ;m ( -- a : meta 'begin' )
:m until talign opJumpZ 2/ t, ;m ( a -- : meta 'until' )
:m again talign opJump 2/ t, ;m ( a -- : meta 'again' )
:m if opJumpZ there 0 t, ;m ( -- a : meta 'if' )
:m tmark opJump there 0 t, ;m ( -- a : meta mark location )
:m then there 2/ swap t! ;m ( a -- : meta 'then' )
:m else tmark swap then ;m ( a -- a : meta 'else' )
:m while if ;m ( -- a : meta 'while' )
:m repeat swap again then ;m ( a a -- : meta 'repeat' )
:m aft drop tmark begin swap ;m ( a -- a a : meta 'aft' )
:m next talign opNext 2/ t, ;m ( a -- : meta 'next' )
:m for opToR begin ;m ( -- a : meta 'for )
:m =jump [ t' opJump half ] literal ;m ( -- a )
:m =jumpz [ t' opJumpZ half ] literal ;m ( -- a )
:m =unnest [ t' opExit half ] literal ;m ( -- a )
:m =>r [ t' opToR half ] literal ;m ( -- a )
:m =next [ t' opNext half ] literal ;m ( -- a )
:m dup opDup ;m ( -- : compile opDup into the dictionary )
:m drop opDrop ;m ( -- : compile opDrop into the dictionary )
:m swap opSwap ;m ( -- : compile opSwap into the dictionary )
:m >r opToR ;m ( -- : compile opTorR into the dictionary )
:m r> opFromR ;m ( -- : compile opFromR into the dictionary )
:m 0= op0= ;m ( -- : compile op0= into the dictionary )
:m mux opMux ;m ( -- : compile opMux into the dictionary )
:m exit opExit ;m ( -- : compile opExit into the dictionary )
:m rshift shift ;m ( -- : compile shift into the dictionary )
:to + + ; ( n n -- n : addition )
:to - - ; ( n1 n2 -- n : subtract n2 from n1 )
:to bye bye ; ( -- : halt the system )
:to dup dup ; ( n -- n n : duplicate top of variable stack )
:to drop opDrop ; ( n -- : drop top of variable stack )
:to swap opSwap ; ( x y -- y x : swap two variables on stack )
:to rshift shift ; ( u n -- u : logical right shift by "n" )
:so [@] [@] ;s ( vma -- : fetch -VM Address- )
:so [!] [!] ;s ( u vma -- : store to -VM Address- )
:to 0= op0= ; ( n -- f : equal to zero )
:so leq0 leq0 ;s ( n -- 0|1 : less than or equal to zero )
:so mux opMux ;s ( u1 u2 sel -- u : bitwise multiplex op. )
:so pause pause ;s ( -- : pause current task, task switch )
: 2* dup + ; ( u -- u : multiply by two )
:s (const) r> [@] ;s compile-only ( R: a --, -- u )
:m constant :t mdrop (const) t, munorder ;m
system[
0 constant #0 ( -- 0 : push the number zero onto the stack )
1 constant #1 ( -- 1 : push one onto the stack )
-1 constant #-1 ( -- -1 : push negative one onto the stack )
2 constant #2 ( -- 2 : push two onto the stack )
-2 constant -cell ( -- -2 : push negative two onto the stack )
]system
: 1+ #1 + ; ( n -- n : increment value in cell )
: 1- #1 - ; ( n -- n : decrement value in cell )
:s (push) r> dup [@] swap 1+ >r ;s ( -- n : inline push value )
:m lit (push) t, ;m ( n -- : compile a literal )
:m literal lit ;m ( n -- : synonym for "lit" )
:m ] ;m ( -- : meta-compiler version of "]", do nothing )
:m [ ;m ( -- : meta-compiler version of "[", do nothing )
:s (up) r> dup [@] [ {up} half ] literal [@] 2* + swap 1+ >r ;s
compile-only ( -- n : user variable implementation word )
:s (var) r> 2* ;s compile-only ( R: a --, -- a )
:s (user) r> [@] [ {up} half ] literal [@] 2* + ;s compile-only
( R: a --, -- u )
:m up (up) t, ;m ( n -- : compile user variable )
:m [char] char (push) t, ;m ( --, "name" : compile char )
:m char char (push) t, ;m ( --, "name" : compile char )
:m variable :t mdrop (var) 0 t, munorder ;m ( --, "name": var )
:m user :t mdrop (user) local? =cell lallot t, munorder ;m
:to ) ; immediate ( -- : NOP, terminate comment )
: over swap dup >r swap r> ; ( n1 n2 -- n1 n2 n1 )
: invert #-1 swap - ; ( u -- u : bitwise invert )
: xor >r dup invert swap r> mux ; ( u u -- u : bitwise xor )
: or over mux ; ( u u -- u : bitwise or )
: and #0 swap mux ; ( u u -- u : bitwise and )
: 2/ #1 rshift ; ( u -- u : divide by two )
: @ 2/ [@] ; ( a -- u : fetch a cell to a memory location )
: ! 2/ [!] ; ( u a -- : write a cell to a memory location )
:s @+ dup @ ;s ( a -- a u : non-destructive load )
user <ok> ( -- a : okay prompt xt loc. )
system[
user <emit> ( -- a : emit xt loc. )
user <key> ( -- a : key xt loc. )
user <echo> ( -- a : echo xt loc. )
user <literal> ( -- a : literal xt loc. )
user <tap> ( -- a : tap xt loc. )
user <expect> ( -- a : expect xt loc. )
user <error> ( -- a : <error> xt container. )
]system
:s <cold> [ {cold} ] literal ;s ( -- a : cold xt loc. )
: current ( -- a : get current vocabulary )
[ {current} ] literal ;
: root-voc ( -- a : get root vocabulary )
[ {root-voc} ] literal ;
: this [ 0 ] up ; ( -- a : address of task thread memory )
: pad this [ 3C0 ] literal + ; ( -- a : index into pad area )
8 constant #vocs ( -- u : number of vocabularies )
: context [ {context} ] literal ; ( -- a )
variable blk ( -- a : loaded block )
variable scr ( -- a : latest listed block )
2F t' scr >tbody t! ( Set default block to list, an empty one )
user base ( -- a : push the radix for numeric I/O )
user dpl ( -- a : decimal point variable )
user hld ( -- a : index to hold space for num. I/O)
user state ( -- f : interpreter state )
user >in ( -- a : input buffer position var )
user span ( -- a : number of chars saved by expect )
$20 constant bl ( -- 32 : push space character )
system[
h constant h? ( -- a : push the location of dict. ptr )
{cycles} constant cycles ( -- a : number of "cycles" ran for )
{sp} constant sp ( -- a : address of v.stk ptr. )
{user} constant user? ( -- a : address of user alloc var )
variable calibration 1400 t' calibration >tbody t!
]system
:s radix base @ ;s ( -- u : retrieve base )
: here h? @ ; ( -- u : push the dictionary pointer )
: sp@ sp @ 1+ ; ( -- a : Fetch variable stack pointer )
: sp! 1- [ {sp} half ] literal [!] #1 drop ;
: rp@ [ {rp} half ] literal [@] 1- ; compile-only
: rp! r> swap [ {rp} half ] literal [!] >r ; compile-only
: hex [ $10 ] literal base ! ; ( -- : hexadecimal base )
: decimal [ $A ] literal base ! ; ( -- : decimal base )
:to ] #-1 state ! ; ( -- : return to compile mode )
:to [ #0 state ! ; immediate ( -- : initiate command mode )
: nip swap drop ; ( x y -- y : remove second item on stack )
: tuck swap over ; ( x y -- y x y : save item for rainy day )
: ?dup dup if dup then ; ( x -- x x | 0 : conditional dup )
: r@ r> r> tuck >r >r ; compile-only ( R: n -- n, -- n )
: rot >r swap r> swap ; ( x y z -- y z x : "rotate" stack )
: -rot rot rot ; ( x y z -- z x y : "rotate" stack backwards )
: 2drop drop drop ; ( x x -- : drop it like it is hot )
: 2dup over over ; ( x y -- x y x y )
:s shed rot drop ;s ( x y z -- y z : drop third stack item )
: = - 0= ; ( u1 u2 -- f : equality )
: <> = 0= ; ( u1 u2 -- f : inequality )
: 0> leq0 0= ; ( n -- f : greater than zero )
: 0<> 0= 0= ; ( n -- f : not equal to zero )
: 0<= 0> 0= ; ( n -- f : less than or equal to zero )
: < ( n1 n2 -- f : less than, is n1 less than n2 )
2dup leq0 swap leq0 if
if
2dup 1+ leq0 swap 1+ leq0
if drop else if 2drop #0 exit then then
else 2drop #-1 exit then \ a0 && !b0
else
if 2drop #0 exit then \ !a0 && b0
then
2dup - leq0 if
swap 1+ swap - leq0 if #-1 exit then
#0 exit
then
2drop #0 ;
: > swap < ; ( n1 n2 -- f : signed greater than )
: 0< #0 < ; ( n -- f : less than zero )
: 0>= 0< 0= ; ( n1 n2 -- f : greater or equal to zero )
: >= < 0= ; ( n1 n2 -- f : greater than or equal to )
: <= > 0= ; ( n1 n2 -- f : less than or equal to )
: u< 2dup 0>= swap 0>= <> >r < r> <> ; ( u1 u2 -- f )
: u> swap u< ; ( u1 u2 -- f : unsigned greater than )
: u>= u< 0= ; ( u1 u2 -- f : unsigned greater or equal to )
: u<= u> 0= ; ( u1 u2 -- f : unsigned less than or equal to )
: within over - >r - r> u< ; ( u lo hi -- f )
: negate 1- invert ; ( n -- n : twos compliment negation )
: s>d dup 0< ; ( n -- d : signed to double width cell )
: abs s>d if negate then ; ( n -- u : absolute value )
2 constant cell ( -- u : push bytes in cells to stack )
: cell+ cell + ; ( a -- a : increment address by cell width )
: cells 2* ; ( u -- u : multiply # of cells to get bytes )
: cell- cell - ; ( a -- a : decrement address by cell width )
: execute 2/ >r ; ( xt -- : execute an execution token )
:s @execute ( ?dup 0= ?exit ) @ execute ;s ( xt -- )
: ?exit if rdrop then ; compile-only ( u --, R: -- |??? )
: key? pause #-1 [@] negate ( -- c 0 | -1 : get byte of input )
s>d if
[ {options} ] literal @
[ 8 ] literal and if bye then drop #0 exit
then #-1 ;
: key begin <key> @execute until ; ( -- c )
: emit <emit> @execute ; ( c -- : output byte )
: cr ( -- : emit new line )
[ =cr ] literal emit
[ =lf ] literal emit ;
: get-current current @ ; ( -- wid : get definitions vocab. )
: set-current current ! ; ( -- wid : set definitions vocab. )
:s last get-current @ ;s ( -- wid : get last defined word )
: pick sp@ + [@] ; ( nu...n0 u -- nu : pick item on stack )
: +! 2/ tuck [@] + swap [!] ; ( u a -- : add val to cell )
: lshift negate shift ; ( u n -- u : left shift 'u' by 'n' )
: c@ ( a -- c : character load )
@+ swap #1 and if
[ 8 ] literal rshift exit
then [ FF ] literal and ;
: c! swap [ FF ] literal and dup [ 8 ] literal lshift or swap
tuck @+ swap #1 and 0= [ FF ] literal xor
>r over xor r> and xor swap ! ; ( c a -- character store )
:s c@+ dup c@ ;s ( b -- b u : non-destructive 'c@' )
: max 2dup > mux ; ( n1 n2 -- n : highest of two numbers )
: min 2dup < mux ; ( n1 n2 -- n : lowest of two numbers )
: source-id [ {id} ] up @ ; ( -- u : input type )
: 2! tuck ! cell+ ! ; ( u1 u2 a -- : store two cells )
: 2@ dup cell+ @ swap @ ; ( a -- u1 u2 : fetch two cells )
: 2>r r> swap >r swap >r >r ; compile-only ( n n --,R: -- n n )
: 2r> r> r> swap r> swap >r ; compile-only ( -- n n,R: n n -- )
system[ user tup =cell tallot ]system
: source tup 2@ ; ( -- a u : get terminal input source )
: aligned dup #1 and 0<> #1 and + ; ( u -- u : align up ptr. )
: align here aligned h? ! ; ( -- : align up dict. ptr. )
: allot h? +! ; ( n -- : allocate space in dictionary )
: , align here ! cell allot ; ( u -- : write value into dict. )
: c, here c! #1 allot ; ( c -- : write character into dict. )
: count dup 1+ swap c@ ; ( b -- b c : advance string )
: +string #1 over min rot over + -rot - ; ( b u -- b u )
:s .emit ( c -- : print char, replacing non-graphic ones )
dup bl [ $7F ] literal within [char] . swap mux emit ;s
: type 1- for count emit next drop ;
: cmove ( b1 b2 n -- : move character blocks around )
#0 max for aft >r c@+ r@ c! 1+ r> 1+ then next 2drop ;
: fill ( b n c -- : write byte 'c' to array 'b' of 'u' length )
swap #0 max for swap aft 2dup c! 1+ then next 2drop ;
: erase #0 fill ; ( b u -- : write zeros to array )
:s do$ 2r> 2* dup count + aligned 2/ >r swap >r ;s ( -- a )
:s ($) do$ ;s ( -- a : do string NB. )
:s .$ do$ count type ;s ( -- : print string in next cells )
:m ." .$ $literal ;m ( --, ccc" : compile string )
:m $" ($) $literal ;m ( --, ccc" : compile string )
: space bl emit ; ( -- : emit a space )
: catch ( xt -- exception# | 0 \ return addr on stack )
sp@ >r ( xt ) \ save data stack pointer
[ {handler} ] up @ >r ( xt ) \ and previous handler
rp@ [ {handler} ] up ! ( xt ) \ set current handler
execute ( ) \ execute returns if no throw
r> [ {handler} ] up ! ( ) \ restore previous handler
rdrop ( ) \ discard saved stack ptr
#0 ; ( 0 ) \ normal completion
: throw ( ??? exception# -- ??? exception# )
?dup if ( exc# ) \ 0 throw is no-op
[ {handler} ] up @ rp! ( exc# ) \ restore prev ret. stack
r> [ {handler} ] up ! ( exc# ) \ restore prev handler
r> swap >r ( saved-sp ) \ exc# on return stack
sp! r> ( exc# ) \ restore stack
then ;
: abort #-1 throw ; ( -- : Time to die. )
:s (abort) do$ swap if count type abort then drop ;s ( n -- )
:s depth [ {sp0} ] literal @ sp@ - 1- ;s ( -- n : stk. depth )
:s ?depth depth >= [ -$4 ] literal and throw ;s ( ??? n -- )
: um+ 2dup + >r r@ 0>= >r ( u u -- u carry )
2dup and 0< r> or >r or 0< r> and negate r> swap ;
: dnegate invert >r invert #1 um+ r> + ; ( d -- d )
: d+ >r swap >r um+ r> + r> + ; ( d d -- d )
: um* ( u u -- ud : double cell width multiply )
#0 swap ( u1 0 u2 )
[ $F ] literal for ( 16 times )
dup um+ 2>r dup um+ r> + r>
if >r over um+ r> + then
next shed ;
: * um* drop ; ( n n -- n : multiply two numbers )
: um/mod ( ud u -- ur uq : unsigned double cell div/mod )
?dup 0= [ -$A ] literal and throw ( divisor is non zero? )
2dup u<
if
negate
[ $F ] literal for ( 16 times )
>r dup um+ 2>r dup um+ r> + dup
r> r@ swap >r um+ r> ( or -> ) 0<> swap 0<> +
if >r drop 1+ r> else drop then r>
next
drop swap exit
then 2drop drop #-1 dup ;
: m/mod ( d n -- r q : floored division, hopefully not flawed )
s>d dup >r
if negate >r dnegate r> then
>r s>d if r@ + then r> um/mod r> ( modify um/mod result )
if swap negate swap then ;
: /mod over 0< swap m/mod ; ( u1 u2 -- u1%u2 u1/u2 )
: mod /mod drop ; ( u1 u2 -- u1%u2 )
: / /mod nip ; ( u1 u2 -- u1/u2 )
:s (emit) pause opEmit ;s ( c -- : output byte to terminal )
: echo <echo> @execute ; ( c -- : emit a single character )
:s tap dup echo over c! 1+ ;s ( bot eot cur c -- bot eot cur )
:s ktap ( bot eot cur c -- bot eot cur )
( Not EOL? )
dup dup [ =cr ] literal <> >r [ =lf ] literal <> r> and if
( Not Del Char? )
dup [ =bksp ] literal <> >r [ =del ] literal <> r> and if
bl tap ( replace any other character with bl )
exit
then
>r over r@ < dup if ( if not at start of line )
[ =bksp ] literal dup echo bl echo echo ( erase char )
then
r> + ( add 0/-1 to cur )
exit
then drop nip dup ;s ( set cur = eot )
: accept ( b u -- b u : read in a line of user input )
over + over begin
2dup <>
while
key dup
bl - [ $5F ] literal u< ( magic: within 32-127? )
if tap else <tap> @execute then
repeat drop over - ;
: expect <expect> @execute span ! drop ; ( a u -- )
: tib source drop ; ( -- b : get Terminal Input Buffer )
: query ( -- : get a new line of input, store it in TIB )
tib [ =buf ] literal <expect> @execute tup ! drop #0 >in ! ;
: -trailing for aft ( b u -- b u : remove trailing spaces )
bl over r@ + c@ < if r> 1+ exit then
then next #0 ;
:s look ( b u c xt -- b u : skip until *xt* test succeeds )
swap >r -rot
begin
dup
while
over c@ r@ - r@ bl = [ 4 ] literal pick execute
if rdrop shed exit then
+string
repeat rdrop shed ;s
:s unmatch if 0> exit then 0<> ;s ( c1 c2 -- t )
:s match unmatch invert ;s ( c1 c2 -- t )
: parse ( c -- b u ; <string> )
>r tib >in @ + tup @ >in @ - r@ ( get memory to parse )
>r over r> swap 2>r
r@ [ t' unmatch ] literal look 2dup ( find start of match )
r> [ t' match ] literal look swap ( find end of match )
r> - >r - r> 1+ ( b u c -- b u delta : compute match len )
>in +!
r> bl = if -trailing then
#0 max ;
:s banner ( +n c -- : output 'c' 'n' times )
>r begin dup 0> while r@ emit 1- repeat drop rdrop ;s
: hold #-1 hld +! hld @ c! ; ( c -- : save char in hold space )
: #> 2drop hld @ this [ =num ] literal + over - ; ( u -- b u )
:s extract ( ud ud -- ud u : extract digit from number )
dup >r um/mod r> swap >r um/mod r> rot ;s
:s digit ( u -- c : extract a character from number )
[ 9 ] literal over < [ 7 ] literal and + [char] 0 + ;s
: # #2 ?depth #0 radix extract digit hold ; ( d -- d )
: #s begin # 2dup ( d0= -> ) or 0= until ; ( d -- 0 )
: <# this [ =num ] literal + hld ! ; ( -- : start num. output )
: sign 0>= ?exit [char] - hold ; ( n -- )
: u.r >r #0 <# #s #> r> over - bl banner type ; ( u r -- )
: u. space #0 u.r ; ( u -- : unsigned numeric output )
opt.divmod [if]
:s (.) abs radix opDivMod ?dup if (.) then digit emit ;s
: . space s>d if [char] - emit then (.) ; ( n -- )
[else]
: . space dup >r abs #0 <# #s r> sign #> type ; ( n -- )
[then]
: >number ( ud b u -- ud b u : convert string to number )
dup 0= ?exit
begin
2dup 2>r drop c@ radix ( get next character )
( digit? -> ) >r [char] 0 - [ 9 ] literal over <
if
( next line: c base -- u f )
[ 7 ] literal - dup [ $A ] literal < or then dup r> u<
0= if ( d char )
drop ( d char -- d )
2r> ( restore string )
exit ( finished...exit )
then ( d char )
swap radix um* drop rot radix um* d+ ( accumulate digit )
2r> ( restore string )
+string dup 0= ( advance, test for end )
until ;
: number? ( a u -- d -1 | a u 0 : easier to use than >number )
#-1 dpl !
radix >r
over c@ [char] - = dup >r if +string then
over c@ [char] $ = if hex +string
( dup 0= if dup rdrop r> base ! exit then )
then
2>r #0 dup 2r>
begin
>number dup