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annotate src/insn_rel.c @ 159:71561c12b20b
Updated docs to reflect new cescapes pragma and discuss implicit assumption of the bss section flag for sections named bss and .bss
| author | lost |
|---|---|
| date | Sat, 31 Jan 2009 06:32:27 +0000 |
| parents | f59c0916753d |
| children |
| rev | line source |
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| 29 | 1 /* |
| 2 insn_rel.c | |
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Added general addressing modes (immediate, base page, extended, indexed)
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3 Copyright © 2009 William Astle |
| 29 | 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 | |
| 32 | 25 #define __insn_rel_c_seen__ |
| 29 | 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 int v; | |
| 77 | 36 lwasm_expr_term_t *t; |
| 37 int r; | |
| 29 | 38 |
| 39 lwasm_emitop(as, l, instab[opnum].ops[0]); | |
| 77 | 40 |
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41 if ((r = lwasm_expr_result2(as, l, p, EXPR_SECTCONST, &v, 0)) < 0) |
| 77 | 42 v = 0; |
| 43 else | |
| 29 | 44 { |
| 77 | 45 if (as -> passnum == 1) |
| 46 { | |
| 47 // need to adjust the expression | |
| 48 if (l -> exprs[0]) | |
| 49 { | |
| 50 t = lwasm_expr_term_create_int(as -> addr + 1); | |
| 51 lwasm_expr_stack_push(l -> exprs[0], t); | |
| 52 lwasm_expr_term_free(t); | |
| 53 t = lwasm_expr_term_create_oper(LWASM_OPER_MINUS); | |
| 54 lwasm_expr_stack_push(l -> exprs[0], t); | |
| 55 lwasm_expr_term_free(t); | |
| 56 } | |
| 57 else | |
| 58 { | |
| 59 l -> exprvals[0] -= as -> addr + 1; | |
| 60 } | |
| 61 } | |
| 29 | 62 } |
| 77 | 63 if (r == 1 && as -> passnum == 2) |
| 64 { | |
| 65 register_error(as, l, 2, "Illegal external or intersegment reference"); | |
| 66 } | |
| 29 | 67 if (v < -128 || v > 127) |
| 68 register_error(as, l, 2, "Byte overflow"); | |
| 69 lwasm_emit(as, l, v & 0xff); | |
| 70 } | |
| 71 | |
| 77 | 72 /* |
| 73 External and intersegment references are adjusted for the relative addressing mode | |
| 74 by adjusting the expression on pass 1 and then treated as absolute references later | |
| 75 */ | |
| 29 | 76 OPFUNC(insn_rel16) |
| 77 { | |
| 78 int v; | |
| 77 | 79 int r; |
| 80 lwasm_expr_term_t *t; | |
| 29 | 81 |
| 82 lwasm_emitop(as, l, instab[opnum].ops[0]); | |
| 83 | |
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84 r = lwasm_expr_result2(as, l, p, EXPR_SECTCONST, &v, 0); |
| 83 | 85 if (r < 0) |
| 59 | 86 v = 0; |
| 77 | 87 else |
| 88 { | |
| 89 if (as -> passnum == 1) | |
| 90 { | |
| 91 // need to adjust the expression | |
| 92 if (l -> exprs[0]) | |
| 93 { | |
| 83 | 94 t = lwasm_expr_term_create_int(as -> addr + 2); |
| 77 | 95 lwasm_expr_stack_push(l -> exprs[0], t); |
| 96 lwasm_expr_term_free(t); | |
| 97 t = lwasm_expr_term_create_oper(LWASM_OPER_MINUS); | |
| 98 lwasm_expr_stack_push(l -> exprs[0], t); | |
| 99 lwasm_expr_term_free(t); | |
| 100 } | |
| 101 else | |
| 102 { | |
| 103 l -> exprvals[0] -= as -> addr + 2; | |
| 104 } | |
| 105 } | |
| 106 } | |
| 107 if (as -> passnum == 2 && r == 1) | |
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108 { |
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109 // since we have a reference outside this section, add |
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110 // a subtract of the section base to get the right value |
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111 // upon linking |
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112 t = lwasm_expr_term_create_secbase(); |
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113 lwasm_expr_stack_push(l -> exprs[0], t); |
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114 lwasm_expr_term_free(t); |
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115 t = lwasm_expr_term_create_oper(LWASM_OPER_MINUS); |
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116 lwasm_expr_stack_push(l -> exprs[0], t); |
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117 lwasm_expr_term_free(t); |
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118 |
| 77 | 119 l -> relocoff = as -> addr - l -> codeaddr; |
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120 } |
| 29 | 121 lwasm_emit(as, l, (v >> 8) & 0xff); |
| 122 lwasm_emit(as, l, v & 0xff); | |
| 123 } |