| 1 | /* Print NS 32000 instructions for GDB, the GNU debugger. |
| 2 | Copyright 1986, 1988, 1991, 1992, 1994, 1995, 1998, 1999, 2000, 2001 |
| 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 | #include "frame.h" |
| 24 | #include "gdbcore.h" |
| 25 | |
| 26 | static int sign_extend (int value, int bits); |
| 27 | |
| 28 | void |
| 29 | _initialize_ns32k_tdep (void) |
| 30 | { |
| 31 | tm_print_insn = print_insn_ns32k; |
| 32 | } |
| 33 | |
| 34 | /* Advance PC across any function entry prologue instructions |
| 35 | to reach some "real" code. */ |
| 36 | |
| 37 | CORE_ADDR |
| 38 | umax_skip_prologue (CORE_ADDR pc) |
| 39 | { |
| 40 | register unsigned char op = read_memory_integer (pc, 1); |
| 41 | if (op == 0x82) |
| 42 | { |
| 43 | op = read_memory_integer (pc + 2, 1); |
| 44 | if ((op & 0x80) == 0) |
| 45 | pc += 3; |
| 46 | else if ((op & 0xc0) == 0x80) |
| 47 | pc += 4; |
| 48 | else |
| 49 | pc += 6; |
| 50 | } |
| 51 | return pc; |
| 52 | } |
| 53 | |
| 54 | /* Return number of args passed to a frame. |
| 55 | Can return -1, meaning no way to tell. |
| 56 | Encore's C compiler often reuses same area on stack for args, |
| 57 | so this will often not work properly. If the arg names |
| 58 | are known, it's likely most of them will be printed. */ |
| 59 | |
| 60 | int |
| 61 | umax_frame_num_args (struct frame_info *fi) |
| 62 | { |
| 63 | int numargs; |
| 64 | CORE_ADDR pc; |
| 65 | CORE_ADDR enter_addr; |
| 66 | unsigned int insn; |
| 67 | unsigned int addr_mode; |
| 68 | int width; |
| 69 | |
| 70 | numargs = -1; |
| 71 | enter_addr = ns32k_get_enter_addr ((fi)->pc); |
| 72 | if (enter_addr > 0) |
| 73 | { |
| 74 | pc = ((enter_addr == 1) |
| 75 | ? SAVED_PC_AFTER_CALL (fi) |
| 76 | : FRAME_SAVED_PC (fi)); |
| 77 | insn = read_memory_integer (pc, 2); |
| 78 | addr_mode = (insn >> 11) & 0x1f; |
| 79 | insn = insn & 0x7ff; |
| 80 | if ((insn & 0x7fc) == 0x57c |
| 81 | && addr_mode == 0x14) /* immediate */ |
| 82 | { |
| 83 | if (insn == 0x57c) /* adjspb */ |
| 84 | width = 1; |
| 85 | else if (insn == 0x57d) /* adjspw */ |
| 86 | width = 2; |
| 87 | else if (insn == 0x57f) /* adjspd */ |
| 88 | width = 4; |
| 89 | else |
| 90 | internal_error (__FILE__, __LINE__, "bad else"); |
| 91 | numargs = read_memory_integer (pc + 2, width); |
| 92 | if (width > 1) |
| 93 | flip_bytes (&numargs, width); |
| 94 | numargs = -sign_extend (numargs, width * 8) / 4; |
| 95 | } |
| 96 | } |
| 97 | return numargs; |
| 98 | } |
| 99 | |
| 100 | static int |
| 101 | sign_extend (int value, int bits) |
| 102 | { |
| 103 | value = value & ((1 << bits) - 1); |
| 104 | return (value & (1 << (bits - 1)) |
| 105 | ? value | (~((1 << bits) - 1)) |
| 106 | : value); |
| 107 | } |
| 108 | |
| 109 | void |
| 110 | flip_bytes (void *p, int count) |
| 111 | { |
| 112 | char tmp; |
| 113 | char *ptr = 0; |
| 114 | |
| 115 | while (count > 0) |
| 116 | { |
| 117 | tmp = *ptr; |
| 118 | ptr[0] = ptr[count - 1]; |
| 119 | ptr[count - 1] = tmp; |
| 120 | ptr++; |
| 121 | count -= 2; |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | /* Return the number of locals in the current frame given a pc |
| 126 | pointing to the enter instruction. This is used in the macro |
| 127 | FRAME_FIND_SAVED_REGS. */ |
| 128 | |
| 129 | int |
| 130 | ns32k_localcount (CORE_ADDR enter_pc) |
| 131 | { |
| 132 | unsigned char localtype; |
| 133 | int localcount; |
| 134 | |
| 135 | localtype = read_memory_integer (enter_pc + 2, 1); |
| 136 | if ((localtype & 0x80) == 0) |
| 137 | localcount = localtype; |
| 138 | else if ((localtype & 0xc0) == 0x80) |
| 139 | localcount = (((localtype & 0x3f) << 8) |
| 140 | | (read_memory_integer (enter_pc + 3, 1) & 0xff)); |
| 141 | else |
| 142 | localcount = (((localtype & 0x3f) << 24) |
| 143 | | ((read_memory_integer (enter_pc + 3, 1) & 0xff) << 16) |
| 144 | | ((read_memory_integer (enter_pc + 4, 1) & 0xff) << 8) |
| 145 | | (read_memory_integer (enter_pc + 5, 1) & 0xff)); |
| 146 | return localcount; |
| 147 | } |
| 148 | |
| 149 | |
| 150 | /* Nonzero if instruction at PC is a return instruction. */ |
| 151 | |
| 152 | static int |
| 153 | ns32k_about_to_return (CORE_ADDR pc) |
| 154 | { |
| 155 | return (read_memory_integer (pc, 1) == 0x12); |
| 156 | } |
| 157 | |
| 158 | |
| 159 | /* |
| 160 | * Get the address of the enter opcode for the function |
| 161 | * containing PC, if there is an enter for the function, |
| 162 | * and if the pc is between the enter and exit. |
| 163 | * Returns positive address if pc is between enter/exit, |
| 164 | * 1 if pc before enter or after exit, 0 otherwise. |
| 165 | */ |
| 166 | |
| 167 | CORE_ADDR |
| 168 | ns32k_get_enter_addr (CORE_ADDR pc) |
| 169 | { |
| 170 | CORE_ADDR enter_addr; |
| 171 | unsigned char op; |
| 172 | |
| 173 | if (pc == 0) |
| 174 | return 0; |
| 175 | |
| 176 | if (ns32k_about_to_return (pc)) |
| 177 | return 1; /* after exit */ |
| 178 | |
| 179 | enter_addr = get_pc_function_start (pc); |
| 180 | |
| 181 | if (pc == enter_addr) |
| 182 | return 1; /* before enter */ |
| 183 | |
| 184 | op = read_memory_integer (enter_addr, 1); |
| 185 | |
| 186 | if (op != 0x82) |
| 187 | return 0; /* function has no enter/exit */ |
| 188 | |
| 189 | return enter_addr; /* pc is between enter and exit */ |
| 190 | } |