1: \ libcc.fs foreign function interface implemented using a C compiler
2:
3: \ Copyright (C) 2006 Free Software Foundation, Inc.
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., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
20:
21:
22: \ What this implementation does is this: if it sees a declaration like
23:
24: \ \ something that tells it to include <unistd.h>
25: \ \ something that tells it that the current library is libc
26:
27: \ c-function dlseek lseek n d n -- d
28:
29: \ it genererates C code similar to the following:
30:
31: \ #include <gforth.h>
32: \ #include <unistd.h>
33: \
34: \ void gforth_c_lseek_ndn_d(void)
35: \ {
36: \ Cell *sp = gforth_SP;
37: \ Float *fp = gforth_FP;
38: \ long long result; /* longest type in C */
39: \ gforth_ll2d(lseek(sp[3],gforth_d2ll(sp[2],sp[1]),sp[0]),sp[3],sp[2]);
40: \ gforth_SP = sp+2;
41: \ }
42:
43: \ Then it compiles this code and dynamically links it into the Gforth
44: \ system (batching and caching are future work). It also dynamically
45: \ links lseek. Performing DLSEEK then puts the function pointer of
46: \ the function pointer of gforth_c_lseek_ndn_d on the stack and
47: \ calls CALL-C.
48:
49: \ other things to do:
50:
51: \ c-variable forth-name c-name
52: \ c-constant forth-name c-name
53:
54:
55: \ data structures
56:
57: \ c-function word body:
58: \ cell function pointer
59: \ char return type index
60: \ char parameter count n
61: \ char*n parameters (type indices)
62: \ counted string: c-name
63:
64: : .n ( n -- )
65: 0 .r ;
66:
67: : const+ ( n1 "name" -- n2 )
68: dup constant 1+ ;
69:
70: wordlist constant libcc-types
71:
72: get-current libcc-types set-current
73:
74: \ index values
75: -1
76: const+ -- \ end of arguments
77: const+ n \ integer cell
78: const+ p \ pointer cell
79: const+ d \ double
80: const+ r \ float
81: const+ func \ C function pointer
82: const+ void
83: drop
84:
85: set-current
86:
87: : parse-libcc-type ( "libcc-type" -- u )
88: parse-name libcc-types search-wordlist 0= -13 and throw execute ;
89:
90: : parse-function-types ( "{libcc-type}" "--" "libcc-type" -- )
91: here 2 chars allot here begin
92: parse-libcc-type dup 0>= while
93: c,
94: repeat
95: drop swap - over char+ c!
96: parse-libcc-type 0< -32 and throw swap c! ;
97:
98: : type-letter ( n -- c )
99: chars s" npdrfv" drop + c@ ;
100:
101: \ count-stacks
102:
103: : count-stacks-n ( fp-change1 sp-change1 -- fp-change2 sp-change2 )
104: 1+ ;
105:
106: : count-stacks-p ( fp-change1 sp-change1 -- fp-change2 sp-change2 )
107: 1+ ;
108:
109: : count-stacks-d ( fp-change1 sp-change1 -- fp-change2 sp-change2 )
110: 2 + ;
111:
112: : count-stacks-r ( fp-change1 sp-change1 -- fp-change2 sp-change2 )
113: swap 1+ swap ;
114:
115: : count-stacks-func ( fp-change1 sp-change1 -- fp-change2 sp-change2 )
116: 1+ ;
117:
118: : count-stacks-void ( fp-change1 sp-change1 -- fp-change2 sp-change2 )
119: ;
120:
121: create count-stacks-types
122: ' count-stacks-n ,
123: ' count-stacks-p ,
124: ' count-stacks-d ,
125: ' count-stacks-r ,
126: ' count-stacks-func ,
127: ' count-stacks-void ,
128:
129: : count-stacks ( pars -- fp-change sp-change )
130: \ pars is an addr u pair
131: 0 0 2swap over + swap u+do
132: i c@ cells count-stacks-type + @ execute
133: loop ;
134:
135: \ gen-pars
136:
137: : gen-par-n ( fp-depth1 sp-depth1 -- fp-depth2 sp-depth2 )
138: 1- dup ." sp[" .n ." ]" ;
139:
140: : gen-par-p ( fp-depth1 sp-depth1 -- fp-depth2 sp-depth2 )
141: ." (void *)(" gen-par-n ." )" ;
142:
143: : gen-par-d ( fp-depth1 sp-depth1 -- fp-depth2 sp-depth2 )
144: ." gforthd2ll(" gen-par-n ." ," gen-par-n ." )" ;
145:
146: : gen-par-r ( fp-depth1 sp-depth1 -- fp-depth2 sp-depth2 )
147: swap 1- tuck ." fp[" .n ." ]" ;
148:
149: : gen-par-func ( fp-depth1 sp-depth1 -- fp-depth2 sp-depth2 )
150: gen-par-p ;
151:
152: : gen-par-void ( fp-depth1 sp-depth1 -- fp-depth2 sp-depth2 )
153: -32 throw ;
154:
155: create gen-par-types
156: ' gen-par-n ,
157: ' gen-par-p ,
158: ' gen-par-d ,
159: ' gen-par-r ,
160: ' gen-par-func ,
161: ' gen-par-void ,
162:
163: : gen-par ( fp-depth1 sp-depth1 partype -- fp-depth2 sp-depth2 )
164: cells gen-par-types @ execute ;
165:
166: \ the call itself
167:
168: : gen-wrapped-call { d: pars d: c-name fp-change1 sp-change1 -- }
169: c-name type ." ("
170: fp-change1 sp-change1 pars over + swap u+do
171: i c@ gen-par
172: i 1+ i' < if
173: ." ,"
174: endif
175: loop
176: 2drop ." )" ;
177:
178: \ calls for various kinds of return values
179:
180: : gen-wrapped-void ( pars c-name fp-change1 sp-change1 -- fp-change sp-change )
181: 2dup 2>r gen-wrapped-call 2r> ;
182:
183: create gen-wrapped-types
184: ' gen-wrapped-n ,
185: ' gen-wrapped-p ,
186: ' gen-wrapped-d ,
187: ' gen-wrapped-r ,
188: ' gen-wrapped-func ,
189: ' gen-wrapped-void ,
190:
191: : gen-wrapped-stmt ( pars c-name fp-change1 sp-change1 ret -- fp-change sp-change )
192: cells gen-wrapped-types @ execute ;
193:
194: : gen-wrapper-function ( addr -- )
195: \ addr points to the return type index of a c-function descriptor
196: c@+ { ret } count 2dup { d: pars } chars + count { d: c-name }
197: ." void gforth_c_" c-name type ." _"
198: pars 0 +do
199: i chars over + c@ type-letter emit
200: loop
201: ." _" ret type-letter emit .\" (void)\n"
202: .\" {\n Cell *sp = gforth_SP;\n Float *fp = gforth_FP;"
203: pars c-name 2over count-stacks ret gen-wrapped-stmt .\" ;\n"
204: ?dup-if
205: ." gforth_SP = sp+" .n .\" ;\n"
206: endif
207: ?dup-if
208: ." gforth_FP = fp+" .n .\" ;\n"
209: endif
210: ." }\n" ;
211:
212: : c-function ( "forth-name" "c-name" "{libcc-type}" "--" "libcc-type" -- )
213: create here >r 0 , \ place for the wrapper function pointer
214: parse-name { d: c-name }
215: parse-function-types c-name string,
216: r> cell+ gen-wrapper-function
217: compile-wrapper-function
218: link-wrapper-function
219: r> !
220: does> ( ... -- ... )
221: @ call-c ;
222:
223:
224:
225:
226:
227: s" Library not found" exception constant err-nolib
228:
229: : library ( "name" "file" -- ) \ gforth
230: \G Dynamically links the library specified by @i{file}. Defines a
231: \G word @i{name} ( -- lib ) that starts the declaration of a
232: \G function from that library.
233: create parse-name open-lib dup 0= err-nolib and throw ,
234: does> ( -- lib )
235: @ ;
236:
237:
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