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comparison src/insn_rel.c @ 29:37aec845aef3

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Added relative addressing handler
author lost
date Fri, 02 Jan 2009 03:27:33 +0000
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children 9bd0fbfe7405
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28:c0ff62e5ad39 29:37aec845aef3
1 /*
2 insn_rel.c
3 Copyright © 2008 William Astle
4
5 This file is part of LWASM.
6
7 LWASM is free software: you can redistribute it and/or modify it under the
8 terms of the GNU General Public License as published by the Free Software
9 Foundation, either version 3 of the License, or (at your option) any later
10 version.
11
12 This program is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 more details.
16
17 You should have received a copy of the GNU General Public License along with
18 this program. If not, see <http://www.gnu.org/licenses/>.
19 */
20
21 /*
22 for handling relative mode instructions
23 */
24
25 #define __insn_inh_c_seen__
26
27 #include <stdlib.h>
28
29 #include "expr.h"
30 #include "lwasm.h"
31 #include "instab.h"
32
33 OPFUNC(insn_rel8)
34 {
35 lwasm_expr_stack_t *s;
36 int v;
37
38 lwasm_emitop(as, l, instab[opnum].ops[0]);
39
40 s = lwasm_expr_eval(*p, NULL);
41 if (!s)
42 {
43 register_error(as, l, 1, "Bad operand");
44 lwasm_emitop(as, l, 0);
45 return;
46 }
47 if (lwasm_expr_is_constant(s))
48 register_error(as, l, 2, "Incomplete reference");
49 v = lwasm_expr_get_value(s);
50 v -= as -> addr + 1;
51 if (v < -128 || v > 127)
52 register_error(as, l, 2, "Byte overflow");
53 lwasm_emit(as, l, v & 0xff);
54
55 lwasm_expr_stack_free(s);
56 }
57
58 OPFUNC(insn_rel16)
59 {
60 lwasm_expr_stack_t *s;
61 int v;
62
63 lwasm_emitop(as, l, instab[opnum].ops[0]);
64
65 s = lwasm_expr_eval(*p, NULL);
66 if (!s)
67 {
68 register_error(as, l, 1, "Bad operand");
69 lwasm_emitop(as, l, 0);
70 return;
71 }
72 if (lwasm_expr_is_constant(s))
73 register_error(as, l, 2, "Incomplete reference");
74 v = lwasm_expr_get_value(s);
75 v -= as -> addr + 2;
76 lwasm_emit(as, l, (v >> 8) & 0xff);
77 lwasm_emit(as, l, v & 0xff);
78
79 lwasm_expr_stack_free(s);
80 }