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comparison lwasm/insn_tfm.c @ 151:427e268e876b

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renamed src to lwasm to better reflect its purpose
author lost
date Fri, 30 Jan 2009 04:01:55 +0000
parents src/insn_tfm.c@74a3fef7c8d0
children bae1e3ecdce1
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150:f0881c115010 151:427e268e876b
1 /*
2 insn_tfm.c
3 Copyright © 2009 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 inherent mode instructions
23 */
24
25 #define __insn_tfm_c_seen__
26
27 #include <ctype.h>
28 #include <string.h>
29
30 #include "lwasm.h"
31 #include "instab.h"
32
33 OPFUNC(insn_tfm)
34 {
35 static const char *reglist = "DXYUS AB 00EF";
36 int r0, r1;
37 char *c;
38 int tfm = 0;
39
40 c = strchr(reglist, toupper(*(*p)++));
41 if (!c)
42 {
43 register_error(as, l, 1, "Unknown operation");
44 return;
45 }
46 r0 = c - reglist;
47 if (**p == '+')
48 {
49 (*p)++;
50 tfm = 1;
51 }
52 else if (**p == '-')
53 {
54 (*p)++;
55 tfm = 2;
56 }
57 if (*(*p)++ != ',')
58 {
59 register_error(as, l, 1, "Unknown operation");
60 return;
61 }
62 c = strchr(reglist, toupper(*(*p)++));
63 if (!c)
64 {
65 register_error(as, l, 1, "Unknown operation");
66 return;
67 }
68 r1 = c - reglist;
69
70 if (**p == '+')
71 {
72 (*p)++;
73 tfm |= 4;
74 }
75 else if (**p == '-')
76 {
77 (*p)++;
78 tfm |= 8;
79 }
80
81 if (**p && !isspace(**p))
82 {
83 register_error(as, l, 1, "Bad operand");
84 return;
85 }
86
87 // valid values of tfm here are:
88 // 1: r0+,r1 (2)
89 // 4: r0,r1+ (3)
90 // 5: r0+,r1+ (0)
91 // 10: r0-,r1- (1)
92 switch (tfm)
93 {
94 case 5: //r0+,r1+
95 lwasm_emitop(as, l, instab[opnum].ops[0]);
96 break;
97 case 10: //r0-,r1-
98 lwasm_emitop(as, l, instab[opnum].ops[1]);
99 break;
100 case 1: // r0+,r1
101 lwasm_emitop(as, l, instab[opnum].ops[2]);
102 break;
103 case 4: // r0,r1+
104 lwasm_emitop(as, l, instab[opnum].ops[3]);
105 break;
106 default:
107 register_error(as, l, 1, "Unknown operation");
108 return;
109 }
110 lwasm_emit(as, l, (r0 << 4) | r1);
111 }