1 \ @(#) member.fth 98/01/26 1.2
2 \ This files, along with c_struct.fth, supports the definition of
3 \ structure members similar to those used in 'C'.
5 \ Some of this same code is also used by ODE,
6 \ the Object Development Environment.
9 \ Copyright 1994 3DO, Phil Burk, Larry Polansky, David Rosenboom
11 \ The pForth software code is dedicated to the public domain,
12 \ and any third party may reproduce, distribute and modify
13 \ the pForth software code or any derivative works thereof
14 \ without any compensation or license. The pForth software
15 \ code is provided on an "as is" basis without any warranty
16 \ of any kind, including, without limitation, the implied
17 \ warranties of merchantability and fitness for a particular
18 \ purpose and their equivalents under the laws of any jurisdiction.
20 \ MOD: PLB 1/16/87 Use abort" instead of er.report.
21 \ MOD: PLB 2/19/87 Made OB.MEMBER immediate, use literal.
22 \ MOD: PLB/MDH 6/7/88 Use 16 bit values in member defs.
23 \ MOD: PLB 7/31/88 Add USHORT and UBYTE.
24 \ MOD: PLB 1/20/89 Treat LITERAL as state sensitive.
25 \ MOD: RDG 9/19/90 Add floating point member support.
26 \ MOD: PLB 6/10/91 Add RPTR
27 \ 00001 PLB 8/3/92 Make RPTR a -4 for S@ and S!
28 \ 941102 RDG port to pforth
29 \ 941108 PLB more porting to pforth. Use ?LITERAL instead os smart literal.
30 \ 960710 PLB align long members for SUN
35 : FIND.BODY ( -- , pfa true | $name false , look for word in dict. )
36 \ Return address of parameter data.
43 \ Variables shared with object oriented code.
44 VARIABLE OB-STATE ( Compilation state. )
45 VARIABLE OB-CURRENT-CLASS ( ABS_CLASS_BASE of current class )
46 1 constant OB_DEF_CLASS ( defining a class )
47 2 constant OB_DEF_STRUCT ( defining a structure )
50 \ cell size of data in bytes (1, 2, cell)
51 \ cell offset within structure
53 cell 1- constant CELL_MASK
54 cell negate constant -CELL
55 cell constant OB_OFFSET_SIZE
57 : OB.OFFSET@ ( member_def -- offset ) @ ;
58 : OB.OFFSET, ( value -- ) , ;
59 : OB.SIZE@ ( member_def -- offset )
61 : OB.SIZE, ( value -- ) , ;
63 ( Members are associated with an offset from the base of a structure. )
64 : OB.MAKE.MEMBER ( +-bytes -- , make room in an object at compile time)
65 dup >r ( -- +-b , save #bytes )
67 ob-current-class @ ( -- b addr-space)
68 tuck @ ( as #b c , current space needed )
69 over CELL_MASK and 0= ( multiple of cell? )
73 over 1 and 0= ( multiple of two? )
78 swap over + rot ! ( update space needed )
79 \ Save data in member definition. %M
80 ob.offset, ( save old offset for ivar )
81 r> ob.size, ( store size in bytes for ..! and ..@ )
84 \ Unions allow one to address the same memory as different members.
85 \ Unions work by saving the current offset for members on
86 \ the stack and then reusing it for different members.
87 : UNION{ ( -- offset , Start union definition. )
91 : }UNION{ ( old-offset -- new-offset , Middle of union )
92 union{ ( Get current for }UNION to compare )
93 swap ob-current-class @ ! ( Set back to old )
96 : }UNION ( offset -- , Terminate union definition, check lengths. )
98 abort" }UNION - Two parts of UNION are not the same size!"
101 \ Make members compile their offset, for "disposable includes".
102 : OB.MEMBER ( #bytes -- , make room in an object at compile time)
103 ( -- offset , run time for structure )
104 CREATE ob.make.member immediate
105 DOES> ob.offset@ ( get offset ) ?literal
108 : OB.FINDIT ( <thing> -- pfa , get pfa of thing or error )
110 IF cr count type ." ???"
111 true abort" OB.FINDIT - Word not found!"
115 : OB.STATS ( member_pfa -- offset #bytes )
120 : OB.STATS? ( <member> -- offset #bytes )
124 : SIZEOF() ( <struct>OR<class> -- #bytes , lookup size of object )
129 \ Basic word for defining structure members.
130 : BYTES ( #bytes -- , error check for structure only )
131 ob-state @ ob_def_struct = not
132 abort" BYTES - Only valid in :STRUCT definitions."
136 \ Declare various types of structure members.
137 \ Negative size indicates a signed member.
138 : BYTE ( <name> -- , declare space for a byte )
141 : SHORT ( <name> -- , declare space for a 16 bit value )
147 : UBYTE ( <name> -- , declare space for signed byte )
150 : USHORT ( <name> -- , declare space for signed 16 bit value )
155 : APTR ( <name> -- ) long ;
156 : RPTR ( <name> -- ) -cell bytes ; \ relative relocatable pointer 00001
157 : ULONG ( <name> -- ) long ;
159 : STRUCT ( <struct> <new_ivar> -- , define a structure as an ivar )
160 [compile] sizeof() bytes