| 1 | /* Print NS 32000 instructions for GDB, the GNU debugger. |
| 2 | Copyright 1986, 1988, 1991, 1992, 1994, 1995 |
| 3 | Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 2 of the License, or |
| 10 | (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, |
| 20 | Boston, MA 02111-1307, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | |
| 24 | void |
| 25 | _initialize_ns32k_tdep (void) |
| 26 | { |
| 27 | tm_print_insn = print_insn_ns32k; |
| 28 | } |
| 29 | |
| 30 | /* Advance PC across any function entry prologue instructions |
| 31 | to reach some "real" code. */ |
| 32 | |
| 33 | CORE_ADDR |
| 34 | merlin_skip_prologue (CORE_ADDR pc) |
| 35 | { |
| 36 | register int op = read_memory_integer (pc, 1); |
| 37 | if (op == 0x82) |
| 38 | { |
| 39 | op = read_memory_integer (pc + 2, 1); |
| 40 | if ((op & 0x80) == 0) |
| 41 | pc += 3; |
| 42 | else if ((op & 0xc0) == 0x80) |
| 43 | pc += 4; |
| 44 | else |
| 45 | pc += 6; |
| 46 | } |
| 47 | return pc; |
| 48 | } |
| 49 | |
| 50 | CORE_ADDR |
| 51 | umax_skip_prologue (CORE_ADDR pc) |
| 52 | { |
| 53 | register unsigned char op = read_memory_integer (pc, 1); |
| 54 | if (op == 0x82) |
| 55 | { |
| 56 | op = read_memory_integer (pc + 2, 1); |
| 57 | if ((op & 0x80) == 0) |
| 58 | pc += 3; |
| 59 | else if ((op & 0xc0) == 0x80) |
| 60 | pc += 4; |
| 61 | else |
| 62 | pc += 6; |
| 63 | } |
| 64 | return pc; |
| 65 | } |
| 66 | |
| 67 | /* Return number of args passed to a frame. |
| 68 | Can return -1, meaning no way to tell. */ |
| 69 | |
| 70 | int |
| 71 | merlin_frame_num_args (struct frame_info *fi) |
| 72 | { |
| 73 | int numargs; |
| 74 | CORE_ADDR pc; |
| 75 | int insn; |
| 76 | int addr_mode; |
| 77 | int width; |
| 78 | |
| 79 | pc = FRAME_SAVED_PC (fi); |
| 80 | insn = read_memory_integer (pc, 2); |
| 81 | addr_mode = (insn >> 11) & 0x1f; |
| 82 | insn = insn & 0x7ff; |
| 83 | if ((insn & 0x7fc) == 0x57c |
| 84 | && addr_mode == 0x14) /* immediate */ |
| 85 | { |
| 86 | if (insn == 0x57c) /* adjspb */ |
| 87 | width = 1; |
| 88 | else if (insn == 0x57d) /* adjspw */ |
| 89 | width = 2; |
| 90 | else if (insn == 0x57f) /* adjspd */ |
| 91 | width = 4; |
| 92 | numargs = read_memory_integer (pc + 2, width); |
| 93 | if (width > 1) |
| 94 | flip_bytes (&numargs, width); |
| 95 | numargs = -sign_extend (numargs, width * 8) / 4; |
| 96 | } |
| 97 | else |
| 98 | numargs = -1; |
| 99 | return numargs; |
| 100 | } |
| 101 | |
| 102 | |
| 103 | /* Return number of args passed to a frame. |
| 104 | Can return -1, meaning no way to tell. |
| 105 | Encore's C compiler often reuses same area on stack for args, |
| 106 | so this will often not work properly. If the arg names |
| 107 | are known, it's likely most of them will be printed. */ |
| 108 | int |
| 109 | umax_frame_num_args (struct frame_info *fi) |
| 110 | { |
| 111 | int numargs; |
| 112 | CORE_ADDR pc; |
| 113 | CORE_ADDR enter_addr; |
| 114 | unsigned int insn; |
| 115 | unsigned int addr_mode; |
| 116 | int width; |
| 117 | |
| 118 | numargs = -1; |
| 119 | enter_addr = ns32k_get_enter_addr ((fi)->pc); |
| 120 | if (enter_addr > 0) |
| 121 | { |
| 122 | pc = ((enter_addr == 1) |
| 123 | ? SAVED_PC_AFTER_CALL (fi) |
| 124 | : FRAME_SAVED_PC (fi)); |
| 125 | insn = read_memory_integer (pc, 2); |
| 126 | addr_mode = (insn >> 11) & 0x1f; |
| 127 | insn = insn & 0x7ff; |
| 128 | if ((insn & 0x7fc) == 0x57c |
| 129 | && addr_mode == 0x14) /* immediate */ |
| 130 | { |
| 131 | if (insn == 0x57c) /* adjspb */ |
| 132 | width = 1; |
| 133 | else if (insn == 0x57d) /* adjspw */ |
| 134 | width = 2; |
| 135 | else if (insn == 0x57f) /* adjspd */ |
| 136 | width = 4; |
| 137 | numargs = read_memory_integer (pc + 2, width); |
| 138 | if (width > 1) |
| 139 | flip_bytes (&numargs, width); |
| 140 | numargs = -sign_extend (numargs, width * 8) / 4; |
| 141 | } |
| 142 | } |
| 143 | return numargs; |
| 144 | } |
| 145 | |
| 146 | |
| 147 | sign_extend (int value, int bits) |
| 148 | { |
| 149 | value = value & ((1 << bits) - 1); |
| 150 | return (value & (1 << (bits - 1)) |
| 151 | ? value | (~((1 << bits) - 1)) |
| 152 | : value); |
| 153 | } |
| 154 | |
| 155 | void |
| 156 | flip_bytes (char *ptr, int count) |
| 157 | { |
| 158 | char tmp; |
| 159 | |
| 160 | while (count > 0) |
| 161 | { |
| 162 | tmp = *ptr; |
| 163 | ptr[0] = ptr[count - 1]; |
| 164 | ptr[count - 1] = tmp; |
| 165 | ptr++; |
| 166 | count -= 2; |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | /* Return the number of locals in the current frame given a pc |
| 171 | pointing to the enter instruction. This is used in the macro |
| 172 | FRAME_FIND_SAVED_REGS. */ |
| 173 | |
| 174 | int |
| 175 | ns32k_localcount (CORE_ADDR enter_pc) |
| 176 | { |
| 177 | unsigned char localtype; |
| 178 | int localcount; |
| 179 | |
| 180 | localtype = read_memory_integer (enter_pc + 2, 1); |
| 181 | if ((localtype & 0x80) == 0) |
| 182 | localcount = localtype; |
| 183 | else if ((localtype & 0xc0) == 0x80) |
| 184 | localcount = (((localtype & 0x3f) << 8) |
| 185 | | (read_memory_integer (enter_pc + 3, 1) & 0xff)); |
| 186 | else |
| 187 | localcount = (((localtype & 0x3f) << 24) |
| 188 | | ((read_memory_integer (enter_pc + 3, 1) & 0xff) << 16) |
| 189 | | ((read_memory_integer (enter_pc + 4, 1) & 0xff) << 8) |
| 190 | | (read_memory_integer (enter_pc + 5, 1) & 0xff)); |
| 191 | return localcount; |
| 192 | } |
| 193 | |
| 194 | |
| 195 | /* Nonzero if instruction at PC is a return instruction. */ |
| 196 | |
| 197 | static int |
| 198 | ns32k_about_to_return (CORE_ADDR pc) |
| 199 | { |
| 200 | return (read_memory_integer (pc, 1) == 0x12); |
| 201 | } |
| 202 | |
| 203 | |
| 204 | /* |
| 205 | * Get the address of the enter opcode for the function |
| 206 | * containing PC, if there is an enter for the function, |
| 207 | * and if the pc is between the enter and exit. |
| 208 | * Returns positive address if pc is between enter/exit, |
| 209 | * 1 if pc before enter or after exit, 0 otherwise. |
| 210 | */ |
| 211 | |
| 212 | CORE_ADDR |
| 213 | ns32k_get_enter_addr (CORE_ADDR pc) |
| 214 | { |
| 215 | CORE_ADDR enter_addr; |
| 216 | unsigned char op; |
| 217 | |
| 218 | if (pc == 0) |
| 219 | return 0; |
| 220 | |
| 221 | if (ns32k_about_to_return (pc)) |
| 222 | return 1; /* after exit */ |
| 223 | |
| 224 | enter_addr = get_pc_function_start (pc); |
| 225 | |
| 226 | if (pc == enter_addr) |
| 227 | return 1; /* before enter */ |
| 228 | |
| 229 | op = read_memory_integer (enter_addr, 1); |
| 230 | |
| 231 | if (op != 0x82) |
| 232 | return 0; /* function has no enter/exit */ |
| 233 | |
| 234 | return enter_addr; /* pc is between enter and exit */ |
| 235 | } |