Annotation of gforth/struct.fs, revision 1.15
1.8 anton 1: \ data structures (like C structs)
2:
1.11 anton 3: \ Copyright (C) 1995, 1997 Free Software Foundation, Inc.
1.8 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:
1.14 anton 21: : naligned ( addr1 n -- addr2 ) \ gforth
1.15 ! crook 22: \g @var{addr2} is the aligned version of @var{addr1} with respect to the
! 23: \g alignment @var{n}.
1.1 anton 24: 1- tuck + swap invert and ;
1.14 anton 25:
26: ' naligned alias nalign \ old name, obsolete
1.1 anton 27:
1.11 anton 28: : dozerofield ( -- )
29: \ a field that makes no change
30: \ to enable accessing the offset with "['] <field> >body @" this
31: \ is not implemented with "['] noop alias"
32: last @
33: if
34: immediate
35: then
1.12 anton 36: does> ( name execution: -- )
1.11 anton 37: drop ;
38:
1.12 anton 39: : field, ( align1 offset1 align size -- align2 offset2 )
1.13 anton 40: swap rot over nalign dup , ( align1 size align offset )
41: rot + >r nalign r> ;
1.12 anton 42:
43: : create-field ( align1 offset1 align size -- align2 offset2 )
44: create field, ;
45:
46: : field ( align1 offset1 align size "name" -- align2 offset2 ) \ gforth
1.15 ! crook 47: \G @code{name} execution: @var{addr1} -- @var{addr2}.
1.12 anton 48: 2 pick
1.11 anton 49: if \ field offset <> 0
50: [IFDEF] (Field)
51: (Field)
52: [ELSE]
53: Header reveal dofield: cfa,
54: [THEN]
55: else
56: create dozerofield
1.12 anton 57: then
58: field, ;
1.1 anton 59:
1.12 anton 60: : end-struct ( align size "name" -- ) \ gforth
1.15 ! crook 61: \g @code{name} execution: @var{addr1} -- @var{addr1+offset1}@*
! 62: \g Create a field @var{name} with offset @var{offset1}, and the type
! 63: \g given by @var{size align}. @var{offset2} is the offset of the
! 64: \g next field, and @var{align2} is the alignment of all fields.
1.12 anton 65: over nalign \ pad size to full alignment
66: 2constant ;
67:
68: 1 chars 0 end-struct struct ( -- align size ) \ gforth
1.15 ! crook 69: \g An empty structure, used to start a structure definition.
1.12 anton 70:
71: \ type descriptors
72: 1 aligned 1 cells 2constant cell% ( -- align size ) \ gforth
73: 1 chars 1 chars 2constant char% ( -- align size ) \ gforth
74: 1 faligned 1 floats 2constant float% ( -- align size ) \ gforth
75: 1 dfaligned 1 dfloats 2constant dfloat% ( -- align size ) \ gforth
76: 1 sfaligned 1 sfloats 2constant sfloat% ( -- align size ) \ gforth
77: cell% 2* 2constant double% ( -- align size ) \ gforth
78:
79: \ memory allocation words
80: ' drop alias %alignment ( align size -- align ) \ gforth
1.15 ! crook 81: \g The alignment of the structure.
1.12 anton 82: ' nip alias %size ( align size -- size ) \ gforth
1.15 ! crook 83: \g The size of the structure.
1.12 anton 84:
85: : %align ( align size -- ) \ gforth
1.15 ! crook 86: \G Align the data space pointer to the alignment @var{align}.
1.12 anton 87: drop here swap nalign here - allot ;
88:
89: : %allot ( align size -- addr ) \ gforth
1.15 ! crook 90: \g Allot @var{size} address units of data space with alignment
! 91: \g @var{align}; the resulting block of data is found at
! 92: \g @var{addr}.
1.12 anton 93: tuck %align
1.2 anton 94: here swap allot ;
95:
1.12 anton 96: : %allocate ( align size -- addr ior ) \ gforth
1.15 ! crook 97: \g Allocate @var{size} address units with alignment @var{align},
1.12 anton 98: \g similar to @code{allocate}.
99: nip allocate ;
100:
101: : %alloc ( size align -- addr ) \ gforth
1.15 ! crook 102: \g Allocate @var{size} address units with alignment @var{align},
! 103: \g giving a data block at @var{addr}; @code{throw} an ior code
1.12 anton 104: \g if not successful.
105: %allocate throw ;
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