| 1 | /* Target-machine dependent code for Hitachi Super-H, for GDB. |
| 2 | Copyright (C) 1993 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 19 | |
| 20 | /* |
| 21 | Contributed by Steve Chamberlain |
| 22 | sac@cygnus.com |
| 23 | */ |
| 24 | |
| 25 | #include "defs.h" |
| 26 | #include "frame.h" |
| 27 | #include "obstack.h" |
| 28 | #include "symtab.h" |
| 29 | #include "gdbtypes.h" |
| 30 | #include "gdbcmd.h" |
| 31 | #include "value.h" |
| 32 | #include "dis-asm.h" |
| 33 | #include "../opcodes/sh-opc.h" |
| 34 | |
| 35 | |
| 36 | |
| 37 | |
| 38 | /* Prologue looks like |
| 39 | [mov.l <regs>,@-r15]... |
| 40 | [sts.l pr,@-r15] |
| 41 | [mov.l r14,@-r15] |
| 42 | [mov r15,r14] |
| 43 | */ |
| 44 | |
| 45 | #define IS_STS(x) ((x) == 0x4f22) |
| 46 | #define IS_PUSH(x) (((x) & 0xff0f) == 0x2f06) |
| 47 | #define GET_PUSHED_REG(x) (((x) >> 4) & 0xf) |
| 48 | #define IS_MOV_SP_FP(x) ((x) == 0x6ef3) |
| 49 | #define IS_ADD_SP(x) (((x) & 0xff00) == 0x7f00) |
| 50 | |
| 51 | |
| 52 | /* Skip any prologue before the guts of a function */ |
| 53 | |
| 54 | CORE_ADDR |
| 55 | sh_skip_prologue (start_pc) |
| 56 | CORE_ADDR start_pc; |
| 57 | |
| 58 | { |
| 59 | int w; |
| 60 | |
| 61 | w = read_memory_integer (start_pc, 2); |
| 62 | while (IS_STS (w) |
| 63 | || IS_PUSH (w) |
| 64 | || IS_MOV_SP_FP (w)) |
| 65 | { |
| 66 | start_pc += 2; |
| 67 | w = read_memory_integer (start_pc, 2); |
| 68 | } |
| 69 | |
| 70 | return start_pc; |
| 71 | } |
| 72 | |
| 73 | /* Disassemble an instruction */ |
| 74 | |
| 75 | int |
| 76 | print_insn (memaddr, stream) |
| 77 | CORE_ADDR memaddr; |
| 78 | FILE *stream; |
| 79 | { |
| 80 | disassemble_info info; |
| 81 | GDB_INIT_DISASSEMBLE_INFO (info, stream); |
| 82 | return print_insn_sh (memaddr, &info); |
| 83 | } |
| 84 | |
| 85 | /* Given a GDB frame, determine the address of the calling function's frame. |
| 86 | This will be used to create a new GDB frame struct, and then |
| 87 | INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame. |
| 88 | |
| 89 | For us, the frame address is its stack pointer value, so we look up |
| 90 | the function prologue to determine the caller's sp value, and return it. */ |
| 91 | |
| 92 | FRAME_ADDR |
| 93 | sh_frame_chain (thisframe) |
| 94 | FRAME thisframe; |
| 95 | { |
| 96 | if (!inside_entry_file (thisframe->pc)) |
| 97 | return (read_memory_integer (FRAME_FP (thisframe), 4)); |
| 98 | else |
| 99 | return 0; |
| 100 | } |
| 101 | |
| 102 | /* Put here the code to store, into a struct frame_saved_regs, |
| 103 | the addresses of the saved registers of frame described by FRAME_INFO. |
| 104 | This includes special registers such as pc and fp saved in special |
| 105 | ways in the stack frame. sp is even more special: |
| 106 | the address we return for it IS the sp for the next frame. */ |
| 107 | |
| 108 | |
| 109 | void |
| 110 | frame_find_saved_regs (fi, fsr) |
| 111 | struct frame_info *fi; |
| 112 | struct frame_saved_regs *fsr; |
| 113 | { |
| 114 | int where[NUM_REGS]; |
| 115 | int rn; |
| 116 | int have_fp = 0; |
| 117 | int depth; |
| 118 | int pc; |
| 119 | int opc; |
| 120 | int insn; |
| 121 | |
| 122 | opc = pc = get_pc_function_start (fi->pc); |
| 123 | |
| 124 | insn = read_memory_integer (pc, 2); |
| 125 | |
| 126 | for (rn = 0; rn < NUM_REGS; rn++) |
| 127 | where[rn] = -1; |
| 128 | |
| 129 | depth = 0; |
| 130 | |
| 131 | /* Loop around examining the prologue insns, but give up |
| 132 | after 15 of them, since we're getting silly then */ |
| 133 | while (pc < opc + 15 * 2) |
| 134 | { |
| 135 | /* See where the registers will be saved to */ |
| 136 | if (IS_PUSH (insn)) |
| 137 | { |
| 138 | pc += 2; |
| 139 | rn = GET_PUSHED_REG (insn); |
| 140 | where[rn] = depth; |
| 141 | insn = read_memory_integer (pc, 2); |
| 142 | depth += 4; |
| 143 | } |
| 144 | else if (IS_STS (insn)) |
| 145 | { |
| 146 | pc += 2; |
| 147 | where[PR_REGNUM] = depth; |
| 148 | insn = read_memory_integer (pc, 2); |
| 149 | depth += 4; |
| 150 | } |
| 151 | else if (IS_ADD_SP (insn)) |
| 152 | { |
| 153 | pc += 2; |
| 154 | depth += -((char) (insn & 0xff)); |
| 155 | insn = read_memory_integer (pc, 2); |
| 156 | } |
| 157 | else |
| 158 | break; |
| 159 | } |
| 160 | |
| 161 | /* Now we know how deep things are, we can work out their addresses */ |
| 162 | |
| 163 | for (rn = 0; rn < NUM_REGS; rn++) |
| 164 | { |
| 165 | if (where[rn] >= 0) |
| 166 | { |
| 167 | if (rn == FP_REGNUM) |
| 168 | have_fp = 1; |
| 169 | |
| 170 | fsr->regs[rn] = fi->frame - where[rn] + depth - 4; |
| 171 | } |
| 172 | else |
| 173 | { |
| 174 | fsr->regs[rn] = 0; |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | if (have_fp) |
| 179 | { |
| 180 | fsr->regs[SP_REGNUM] = read_memory_integer (fsr->regs[FP_REGNUM], 4); |
| 181 | } |
| 182 | else |
| 183 | { |
| 184 | fsr->regs[SP_REGNUM] = fi->frame - 4; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | /* Work out the return pc - either from the saved pr or the pr |
| 189 | value */ |
| 190 | |
| 191 | if (fsr->regs[PR_REGNUM]) |
| 192 | { |
| 193 | fi->return_pc = read_memory_integer (fsr->regs[PR_REGNUM], 4) + 4; |
| 194 | } |
| 195 | else |
| 196 | { |
| 197 | fi->return_pc = read_register (PR_REGNUM) + 4; |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | /* initialize the extra info saved in a FRAME */ |
| 202 | |
| 203 | void |
| 204 | init_extra_frame_info (fromleaf, fi) |
| 205 | int fromleaf; |
| 206 | struct frame_info *fi; |
| 207 | { |
| 208 | struct frame_saved_regs dummy; |
| 209 | frame_find_saved_regs (fi, &dummy); |
| 210 | } |
| 211 | |
| 212 | |
| 213 | /* Discard from the stack the innermost frame, |
| 214 | restoring all saved registers. */ |
| 215 | |
| 216 | void |
| 217 | pop_frame () |
| 218 | { |
| 219 | register FRAME frame = get_current_frame (); |
| 220 | register CORE_ADDR fp; |
| 221 | register int regnum; |
| 222 | struct frame_saved_regs fsr; |
| 223 | struct frame_info *fi; |
| 224 | |
| 225 | fi = get_frame_info (frame); |
| 226 | fp = fi->frame; |
| 227 | get_frame_saved_regs (fi, &fsr); |
| 228 | |
| 229 | /* Copy regs from where they were saved in the frame */ |
| 230 | for (regnum = 0; regnum < NUM_REGS; regnum++) |
| 231 | { |
| 232 | if (fsr.regs[regnum]) |
| 233 | { |
| 234 | write_register (regnum, read_memory_integer (fsr.regs[regnum], 4)); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | write_register (PC_REGNUM, fi->return_pc); |
| 239 | write_register (SP_REGNUM, fp + 4); |
| 240 | flush_cached_frames (); |
| 241 | set_current_frame (create_new_frame (read_register (FP_REGNUM), |
| 242 | read_pc ())); |
| 243 | } |
| 244 | |
| 245 | |
| 246 | _initialize_sh_tdep () |
| 247 | { |
| 248 | extern int sim_memory_size; |
| 249 | /* FIXME, there should be a way to make a CORE_ADDR variable settable. */ |
| 250 | add_show_from_set |
| 251 | (add_set_cmd ("memory_size", class_support, var_uinteger, |
| 252 | (char *) &sim_memory_size, |
| 253 | "Set simulated memory size of simulator target.", &setlist), |
| 254 | &showlist); |
| 255 | } |