Annotation of gforth/kernel/basics.fs, revision 1.62

1.1       anton       1: \ kernel.fs    GForth kernel                        17dec92py
                      2: 
1.61      anton       3: \ Copyright (C) 1995,1998,2000,2003,2004,2005,2006,2007 Free Software Foundation, Inc.
1.1       anton       4: 
                      5: \ This file is part of Gforth.
                      6: 
                      7: \ Gforth is free software; you can redistribute it and/or
                      8: \ modify it under the terms of the GNU General Public License
1.62    ! anton       9: \ as published by the Free Software Foundation, either version 3
1.1       anton      10: \ of the License, or (at your option) any later version.
                     11: 
                     12: \ This program is distributed in the hope that it will be useful,
                     13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
                     14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     15: \ GNU General Public License for more details.
                     16: 
                     17: \ You should have received a copy of the GNU General Public License
1.62    ! anton      18: \ along with this program. If not, see http://www.gnu.org/licenses/.
1.1       anton      19: 
                     20: \ Idea and implementation: Bernd Paysan (py)
                     21: 
1.16      jwilke     22: \ Needs:
                     23: 
                     24: require ./vars.fs
1.32      anton      25: require ../compat/strcomp.fs
1.16      jwilke     26: 
                     27: hex
1.1       anton      28: 
                     29: \ labels for some code addresses
                     30: 
                     31: \- NIL NIL AConstant NIL \ gforth
                     32: 
                     33: \ Aliases
                     34: 
1.4       jwilke     35: [IFUNDEF] r@
1.1       anton      36: ' i Alias r@ ( -- w ; R: w -- w ) \ core r-fetch
1.4       jwilke     37: [THEN]
1.1       anton      38: 
                     39: \ !! this is machine-dependent, but works on all but the strangest machines
                     40: 
1.23      anton      41: : maxaligned ( addr1 -- addr2 ) \ gforth
                     42:     \G @i{addr2} is the first address after @i{addr1} that satisfies
                     43:     \G all alignment restrictions.
1.1       anton      44:     [ /maxalign 1 - ] Literal + [ 0 /maxalign - ] Literal and ;
1.23      anton      45: \ !! machine-dependent and won't work if "0 >body" <> "0 >body
                     46:     \G maxaligned"
1.1       anton      47: ' maxaligned Alias cfaligned ( addr1 -- addr2 ) \ gforth
1.23      anton      48: \G @i{addr2} is the first address after @i{addr1} that is aligned for
                     49: \G a code field (i.e., such that the corresponding body is maxaligned).
1.1       anton      50: 
                     51: : chars ( n1 -- n2 ) \ core
1.23      anton      52: \G @i{n2} is the number of address units of @i{n1} chars.""
1.1       anton      53: ; immediate
                     54: 
                     55: 
                     56: \ : A!    ( addr1 addr2 -- ) \ gforth
                     57: \    dup relon ! ;
                     58: \ : A,    ( addr -- ) \ gforth
                     59: \    here cell allot A! ;
                     60: ' ! alias A! ( addr1 addr2 -- ) \ gforth
                     61: 
1.2       anton      62: \ UNUSED                                                17may93jaw
                     63: 
1.41      pazsan     64: has? ec [IF]
1.30      jwilke     65: unlock ram-dictionary borders nip lock
                     66: AConstant dictionary-end
1.4       jwilke     67: [ELSE]
1.35      pazsan     68:     has? header [IF]
                     69:        : dictionary-end ( -- addr )
                     70:            forthstart [ 3 cells image-header + ] Aliteral @ + ;
                     71:     [ELSE]
                     72:        : forthstart 0 ;
                     73:        : dictionary-end ( -- addr )
                     74:            forthstart [ has? kernel-size ] Literal + ;
                     75:     [THEN]
1.4       jwilke     76: [THEN]
1.2       anton      77: 
1.14      anton      78: : usable-dictionary-end ( -- addr )
                     79:     dictionary-end [ word-pno-size pad-minsize + ] Literal - ;
                     80: 
1.2       anton      81: : unused ( -- u ) \ core-ext
1.13      crook      82:     \G Return the amount of free space remaining (in address units) in
                     83:     \G the region addressed by @code{here}.
1.14      anton      84:     usable-dictionary-end here - ;
1.2       anton      85: 
1.40      pazsan     86: has? ec [IF]
                     87: : in-dictionary? ( x -- f )
1.41      pazsan     88:     dictionary-end u< ;
1.40      pazsan     89: [ELSE]    
1.34      anton      90: : in-dictionary? ( x -- f )
                     91:     forthstart dictionary-end within ;
1.40      pazsan     92: [THEN]
1.34      anton      93: 
1.1       anton      94: \ here is used for pad calculation!
                     95: 
                     96: : dp    ( -- addr ) \ gforth
                     97:     dpp @ ;
1.13      crook      98: : here  ( -- addr ) \ core
                     99:     \G Return the address of the next free location in data space.
1.1       anton     100:     dp @ ;
                    101: 
                    102: \ on off                                               23feb93py
                    103: 
1.4       jwilke    104: \ on is used by docol:
1.15      crook     105: : on  ( a-addr -- ) \ gforth
                    106:     \G Set the (value of the) variable  at @i{a-addr} to @code{true}.
1.1       anton     107:     true  swap ! ;
1.15      crook     108: : off ( a-addr -- ) \ gforth
                    109:     \G Set the (value of the) variable at @i{a-addr} to @code{false}.
1.1       anton     110:     false swap ! ;
                    111: 
                    112: \ dabs roll                                           17may93jaw
                    113: 
1.24      anton     114: : dabs ( d -- ud ) \ double d-abs
1.1       anton     115:     dup 0< IF dnegate THEN ;
                    116: 
                    117: : roll  ( x0 x1 .. xn n -- x1 .. xn x0 ) \ core-ext
1.47      anton     118:     \  dup 1+ pick >r
                    119:     \  cells sp@ cell+ dup cell+ rot move drop r> ;
                    120:     dup 0<= if
                    121:        drop
                    122:     else
1.54      pazsan    123:        swap >r 1- recurse r> swap 
1.47      anton     124:     then ;
1.1       anton     125: 
                    126: \ place bounds                                         13feb93py
                    127: 
                    128: : place  ( addr len to -- ) \ gforth
                    129:     over >r  rot over 1+  r> move c! ;
1.27      anton     130: : bounds ( addr u -- addr+u addr ) \ gforth
                    131:     \G Given a memory block represented by starting address @i{addr}
                    132:     \G and length @i{u} in aus, produce the end address @i{addr+u} and
                    133:     \G the start address in the right order for @code{u+do} or
                    134:     \G @code{?do}.
1.1       anton     135:     over + swap ;
                    136: 
                    137: \ (word)                                               22feb93py
                    138: 
                    139: : scan   ( addr1 n1 char -- addr2 n2 ) \ gforth
1.43      anton     140:     \G skip all characters not equal to char
1.1       anton     141:     >r
                    142:     BEGIN
                    143:        dup
                    144:     WHILE
                    145:        over c@ r@ <>
                    146:     WHILE
                    147:        1 /string
                    148:     REPEAT  THEN
                    149:     rdrop ;
                    150: : skip   ( addr1 n1 char -- addr2 n2 ) \ gforth
1.43      anton     151:     \G skip all characters equal to char
1.1       anton     152:     >r
                    153:     BEGIN
                    154:        dup
                    155:     WHILE
                    156:        over c@ r@  =
                    157:     WHILE
                    158:        1 /string
                    159:     REPEAT  THEN
                    160:     rdrop ;
                    161: 
                    162: \ digit?                                               17dec92py
                    163: 
                    164: : digit?   ( char -- digit true/ false ) \ gforth
                    165:   toupper [char] 0 - dup 9 u> IF
1.16      jwilke    166:     [ char A char 9 1 + -  ] literal -
1.1       anton     167:     dup 9 u<= IF
                    168:       drop false EXIT
                    169:     THEN
                    170:   THEN
                    171:   dup base @ u>= IF
                    172:     drop false EXIT
                    173:   THEN
                    174:   true ;
                    175: 
                    176: : accumulate ( +d0 addr digit - +d1 addr )
1.40      pazsan    177:   swap >r swap  base @  um* drop rot  base @  um* d+ r> ;
1.1       anton     178: 
1.18      crook     179: : >number ( ud1 c-addr1 u1 -- ud2 c-addr2 u2 ) \ core to-number
1.22      anton     180:     \G Attempt to convert the character string @var{c-addr1 u1} to an
1.13      crook     181:     \G unsigned number in the current number base. The double
                    182:     \G @var{ud1} accumulates the result of the conversion to form
                    183:     \G @var{ud2}. Conversion continues, left-to-right, until the whole
                    184:     \G string is converted or a character that is not convertable in
                    185:     \G the current number base is encountered (including + or -). For
                    186:     \G each convertable character, @var{ud1} is first multiplied by
                    187:     \G the value in @code{BASE} and then incremented by the value
                    188:     \G represented by the character. @var{c-addr2} is the location of
                    189:     \G the first unconverted character (past the end of the string if
                    190:     \G the whole string was converted). @var{u2} is the number of
                    191:     \G unconverted characters in the string. Overflow is not detected.
1.1       anton     192:     0
                    193:     ?DO
                    194:        count digit?
                    195:     WHILE
                    196:        accumulate
                    197:     LOOP
                    198:         0
                    199:     ELSE
                    200:        1- I' I -
                    201:        UNLOOP
                    202:     THEN ;
                    203: 
                    204: \ s>d um/mod                                           21mar93py
                    205: 
                    206: : s>d ( n -- d ) \ core                s-to-d
                    207:     dup 0< ;
                    208: 
                    209: : ud/mod ( ud1 u2 -- urem udquot ) \ gforth
                    210:     >r 0 r@ um/mod r> swap >r
                    211:     um/mod r> ;
                    212: 
                    213: \ catch throw                                          23feb93py
                    214: 
1.5       jwilke    215: has? glocals [IF]
1.12      crook     216: : lp@ ( -- addr ) \ gforth     lp-fetch
1.1       anton     217:  laddr# [ 0 , ] ;
                    218: [THEN]
                    219: 
1.59      pazsan    220: has? os 0= [IF]
1.52      pazsan    221:     : catch  ( ... xt -- ... 0 )
                    222:        handler @ >r sp@ >r
                    223:        rp@ handler ! execute 0 r> drop r> handler ! ;
                    224:     : throw  ( error -- error )  dup 0= IF  drop EXIT  THEN
                    225:        handler @ rp! r> swap >r sp! r> r> handler ! ;
                    226: [ELSE]
1.17      anton     227: defer catch ( x1 .. xn xt -- y1 .. ym 0 / z1 .. zn error ) \ exception
1.24      anton     228: \G @code{Executes} @i{xt}.  If execution returns normally,
                    229: \G @code{catch} pushes 0 on the stack.  If execution returns through
                    230: \G @code{throw}, all the stacks are reset to the depth on entry to
                    231: \G @code{catch}, and the TOS (the @i{xt} position) is replaced with
                    232: \G the throw code.
                    233: 
1.17      anton     234: :noname ( ... xt -- ... 0 )
                    235:     execute 0 ;
                    236: is catch
1.1       anton     237: 
1.24      anton     238: defer throw ( y1 .. ym nerror -- y1 .. ym / z1 .. zn error ) \ exception
                    239: \G If @i{nerror} is 0, drop it and continue.  Otherwise, transfer
                    240: \G control to the next dynamically enclosing exception handler, reset
                    241: \G the stacks accordingly, and push @i{nerror}.
                    242: 
                    243: :noname ( y1 .. ym error -- y1 .. ym / z1 .. zn error )
1.19      anton     244:     ?dup if
1.35      pazsan    245:        [ has? header [IF] here image-header 9 cells + ! [THEN] ]
1.60      pazsan    246:        cr DoError cr
1.21      pazsan    247:        [ has? file [IF] ] script? IF  1 (bye)  ELSE  quit  THEN
                    248:        [ [ELSE] ] quit [ [THEN] ]
1.19      anton     249:     then ;
1.56      pazsan    250: is throw
1.52      pazsan    251: [THEN]
1.19      anton     252: 
1.1       anton     253: \ (abort")
                    254: 
1.33      anton     255: : c(abort") ( c-addr -- )
                    256:     "error ! -2 throw ;
                    257: 
1.1       anton     258: : (abort")
                    259:     "lit >r
                    260:     IF
                    261:        r> "error ! -2 throw
                    262:     THEN
                    263:     rdrop ;
1.6       pazsan    264: 
                    265: : abort ( ?? -- ?? ) \ core,exception-ext
1.12      crook     266:     \G @code{-1 throw}.
1.6       pazsan    267:     -1 throw ;
1.1       anton     268: 
                    269: \ ?stack                                               23feb93py
                    270: 
                    271: : ?stack ( ?? -- ?? ) \ gforth
1.3       jwilke    272:     sp@ sp0 @ u> IF    -4 throw  THEN
1.5       jwilke    273: [ has? floating [IF] ]
1.3       jwilke    274:     fp@ fp0 @ u> IF  -&45 throw  THEN
1.1       anton     275: [ [THEN] ]
                    276: ;
                    277: \ ?stack should be code -- it touches an empty stack!
                    278: 
                    279: \ DEPTH                                                 9may93jaw
                    280: 
1.9       crook     281: : depth ( -- +n ) \ core depth
1.12      crook     282:     \G @var{+n} is the number of values that were on the data stack before
                    283:     \G @var{+n} itself was placed on the stack.
1.3       jwilke    284:     sp@ sp0 @ swap - cell / ;
1.9       crook     285: 
                    286: : clearstack ( ... -- ) \ gforth clear-stack
1.42      anton     287: \G remove and discard all/any items from the data stack.
1.3       jwilke    288:     sp0 @ sp! ;
1.42      anton     289: 
                    290: : clearstacks ( ... -- ) \ gforth clear-stacks
                    291: \G empty data and FP stack
1.49      pazsan    292:     clearstack
                    293: [ has? floating [IF] ]
                    294:     fp0 @ fp!
                    295: [ [THEN] ]
                    296: ;
1.1       anton     297: 
                    298: \ Strings                                               22feb93py
                    299: 
                    300: : "lit ( -- addr )
                    301:   r> r> dup count + aligned >r swap >r ;
                    302: 
                    303: \ HEX DECIMAL                                           2may93jaw
                    304: 
                    305: : decimal ( -- ) \ core
1.58      anton     306:     \G Set @code{base} to &10 (decimal).  Don't use @code{hex}, use
                    307:     \G @code{base-execute} instead.
1.1       anton     308:     a base ! ;
                    309: : hex ( -- ) \ core-ext
1.58      anton     310:     \G Set @code{base} to &16 (hexadecimal).  Don't use @code{hex},
                    311:     \G use @code{base-execute} instead.
1.1       anton     312:     10 base ! ;
                    313: 

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