Annotation of gforth/float.fs, revision 1.25

1.1       anton       1: \ High level floating point                            14jan94py
                      2: 
1.23      anton       3: \ Copyright (C) 1995,1997 Free Software Foundation, Inc.
1.18      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
                      9: \ as published by the Free Software Foundation; either version 2
                     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
                     18: \ along with this program; if not, write to the Free Software
                     19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
                     20: 
1.17      anton      21: \ 1 cells 4 = [IF]
                     22: \ ' cells   Alias sfloats
                     23: \ ' cell+   Alias sfloat+
                     24: \ ' align   Alias sfalign
                     25: \ ' aligned Alias sfaligned
                     26: \ [ELSE]
                     27: \ : sfloats  2* 2* ;
                     28: \ : sfloat+  4 + ;
                     29: \ : sfaligned ( addr -- addr' )  3 + -4 and ;
                     30: \ : sfalign ( -- )  here dup sfaligned swap ?DO  bl c,  LOOP ;
                     31: \ [THEN]
1.6       pazsan     32: 
1.17      anton      33: \ 1 floats 8 = [IF]
                     34: \ ' floats   Alias dfloats
                     35: \ ' float+   Alias dfloat+
                     36: \ ' falign   Alias dfalign
                     37: \ ' faligned Alias dfaligned
                     38: \ [ELSE]
                     39: \ : dfloats  2* 2* 2* ;
                     40: \ : dfloat+  8 + ;
                     41: \ : dfaligned ( addr -- addr' )  7 + -8 and ;
                     42: \ : dfalign ( -- )  here dup dfaligned swap ?DO  bl c,  LOOP ;
                     43: \ [THEN]
                     44: 
                     45: : sfalign ( -- ) \ float-ext s-f-align
                     46:     here dup sfaligned swap ?DO  bl c,  LOOP ;
                     47: : dfalign ( -- ) \ float-ext d-f-align
                     48:     here dup dfaligned swap ?DO  bl c,  LOOP ;
                     49: 
                     50: 1 sfloats constant sfloat+ ( sf-addr1 -- sf-addr2 ) \ float-ext s-float-plus
                     51: dofield: lastxt code-address! \ change the constant into a field
                     52: 
                     53: 1 dfloats constant dfloat+ ( df-addr1 -- df-addr2 ) \ float-ext d-float-plus
                     54: dofield: lastxt code-address! \ change the constant into a field
1.6       pazsan     55: 
1.1       anton      56: : f, ( f -- )  here 1 floats allot f! ;
                     57: 
1.20      anton      58: : fconstant  ( r "name" -- ) \ float
1.13      anton      59:     Create f,
1.16      anton      60: DOES> ( -- r )
                     61:     f@ ;
1.1       anton      62: 
1.24      crook      63: : fdepth ( -- +n ) \ floating f-depth
1.25    ! crook      64:     \G @var{+n} is the current number of (floating-point) values on the
1.24      crook      65:     \G floating-point stack.
                     66:     fp0 @ fp@ - [ 1 floats ] Literal / ;
1.1       anton      67: 
1.14      pazsan     68: : FLit ( -- r )  r> dup f@ float+ >r ;
1.24      crook      69: : FLiteral ( compilation r -- ; run-time -- r ) \ float
1.25    ! crook      70:     \G Compile appropriate code such that, at run-time, @var{r} is placed
1.24      crook      71:     \G on the (floating-point) stack. Interpretation semantics are undefined.
                     72:     BEGIN  here cell+ dup faligned <>  WHILE  postpone noop  REPEAT
                     73:     postpone FLit  f, ;  immediate
                     74: 
                     75: &15 Value precision ( -- u ) \ floating-ext
1.25    ! crook      76: \G @var{u} is the number of significant digits currently used by
1.24      crook      77: \G @code{F.} @code{FE.} and @code{FS.} 
                     78: : set-precision ( u -- ) \ floating-ext
                     79:     \G Set the number of significant digits currently used by
1.25    ! crook      80:     \G @code{F.} @code{FE.} and @code{FS.} to @var{u}.
1.24      crook      81:     to precision ;
1.1       anton      82: 
                     83: : scratch ( r -- addr len )
                     84:   pad precision - precision ;
                     85: 
                     86: : zeros ( n -- )   0 max 0 ?DO  '0 emit  LOOP ;
                     87: 
                     88: : -zeros ( addr u -- addr' u' )
                     89:   BEGIN  dup  WHILE  1- 2dup + c@ '0 <>  UNTIL  1+  THEN ;
                     90: 
1.4       pazsan     91: : f$ ( f -- n )  scratch represent 0=
                     92:   IF  2drop  scratch 3 min type  rdrop  EXIT  THEN
                     93:   IF  '- emit  THEN ;
                     94: 
1.24      crook      95: : f.  ( r -- ) \ floating-ext f-dot
1.25    ! crook      96: \G Display (the floating-point number) @var{r} using fixed-point notation,
1.24      crook      97: \G followed by a space.
                     98:   f$ dup >r 0<
1.4       pazsan     99:   IF    '0 emit
1.1       anton     100:   ELSE  scratch r@ min type  r@ precision - zeros  THEN
                    101:   '. emit r@ negate zeros
                    102:   scratch r> 0 max /string 0 max -zeros type space ;
1.3       benschop  103: \ I'm afraid this does not really implement ansi semantics wrt precision.
                    104: \ Shouldn't precision indicate the number of places shown after the point?
1.1       anton     105: 
1.24      crook     106: : fe. ( r -- ) \ floating-ext f-e-dot
1.25    ! crook     107: \G Display @var{r} using engineering notation, followed by a space.
1.24      crook     108:   f$ 1- s>d 3 fm/mod 3 * >r 1+ >r
1.1       anton     109:   scratch r@ min type '. emit  scratch r> /string type
                    110:   'E emit r> . ;
                    111: 
1.24      crook     112: : fs. ( r -- ) \ floating-ext f-s-dot
1.25    ! crook     113: \G Display @var{r} using scientific notation, followed by a space.
1.24      crook     114:   f$ 1-
1.4       pazsan    115:   scratch over c@ emit '. emit 1 /string type
                    116:   'E emit . ;
                    117: 
1.21      anton     118: require debugs.fs
1.16      anton     119: 
1.19      anton     120: : sfnumber ( c-addr u -- r true | false )
                    121:     2dup [CHAR] e scan ( c-addr u c-addr2 u2 )
1.16      anton     122:     dup 0=
                    123:     IF
1.19      anton     124:        2drop 2dup [CHAR] E scan ( c-addr u c-addr3 u3 )
1.16      anton     125:     THEN
                    126:     nip
1.7       anton     127:     IF
1.19      anton     128:        >float
                    129:     ELSE
                    130:        2drop false
                    131:     THEN ;
                    132: 
                    133: :noname ( c-addr u -- )
                    134:     2dup sfnumber
                    135:     IF
                    136:        2drop POSTPONE FLiteral
                    137:     ELSE
                    138:        defers compiler-notfound
                    139:     ENDIF ;
                    140: IS compiler-notfound
1.1       anton     141: 
1.19      anton     142: :noname ( c-addr u -- r )
                    143:     2dup sfnumber
                    144:     IF
                    145:        2drop
                    146:     ELSE
                    147:        defers interpreter-notfound
                    148:     ENDIF ;
                    149: IS interpreter-notfound
1.13      anton     150: 
1.20      anton     151: : fvariable ( "name" -- ) \ float
1.15      pazsan    152:     Create 0.0E0 f, ;
1.13      anton     153:     \ does> ( -- f-addr )
1.1       anton     154: 
1.24      crook     155: 1.0e0 fasin 2.0e0 f* fconstant pi ( -- r ) \ gforth
1.25    ! crook     156: \G FCONSTANT: @var{r} is the value pi; the ratio of a circle's area
1.24      crook     157: \G to its diameter.
                    158: 
                    159: : f2* ( r1 -- r2 ) \ gforth
1.25    ! crook     160:     \G Multiply @var{r1} by 2.0e0
1.24      crook     161:     2.0e0 f* ;
                    162: 
                    163: : f2/ ( r1 -- r2 ) \ gforth
1.25    ! crook     164:     \G Multiply @var{r1} by 0.5e0
1.24      crook     165:     0.5e0 f* ;
                    166: 
                    167: : 1/f ( r1 -- r2 ) \ gforth
1.25    ! crook     168:     \G Divide 1.0e0 by @var{r1}.
1.24      crook     169:     1.0e0 fswap f/ ;
1.6       pazsan    170: 
                    171: 
1.10      anton     172: \ We now have primitives for these, so we need not define them
1.6       pazsan    173: 
1.15      pazsan    174: \ : falog ( f -- 10^f )  [ 10.0e0 fln ] FLiteral f* fexp ;
1.10      anton     175: 
1.15      pazsan    176: \ : fsinh    fexpm1 fdup fdup 1.0e0 f+ f/ f+ f2/ ;
1.10      anton     177: \ : fcosh    fexp fdup 1/f f+ f2/ ;
1.15      pazsan    178: \ : ftanh    f2* fexpm1 fdup 2.0e0 f+ f/ ;
1.10      anton     179: 
1.15      pazsan    180: \ : fatanh   fdup f0< >r fabs 1.0e0 fover f- f/  f2* flnp1 f2/
1.10      anton     181: \            r> IF  fnegate  THEN ;
1.15      pazsan    182: \ : facosh   fdup fdup f* 1.0e0 f- fsqrt f+ fln ;
                    183: \ : fasinh   fdup fdup f* 1.0e0 f+ fsqrt f/ fatanh ;
1.9       pazsan    184: 
1.16      anton     185: \ !! factor out parts
                    186: : f~ ( f1 f2 f3 -- flag ) \ float-ext
                    187:     fdup f0=
                    188:     IF
                    189:        fdrop f= EXIT
                    190:     THEN
                    191:     fdup f0>
                    192:     IF
                    193:        frot frot f- fabs fswap
                    194:     ELSE
                    195:        fnegate frot frot fover fabs fover fabs f+ frot frot
                    196:        f- fabs frot frot f*
                    197:     THEN
                    198:     f< ;
1.11      pazsan    199: 
1.24      crook     200: : f.s ( -- ) \ gforth f-dot-s
                    201:     \G Display the number of items on the floating-point stack,
                    202:     \G followed by a list of the items; TOS is the right-most item.
                    203:     ." <" fdepth 0 .r ." > " fdepth 0 max maxdepth-.s @ min dup 0 
                    204:     ?DO  dup i - 1- floats fp@ + f@ f.  LOOP  drop ; 

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