| /* Print NS 32000 instructions for GDB, the GNU debugger. |
| Copyright 1986, 1988, 1991, 1992, 1994, 1995 |
| Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| |
| void |
| _initialize_ns32k_tdep () |
| { |
| tm_print_insn = print_insn_ns32k; |
| } |
| |
| /* Advance PC across any function entry prologue instructions |
| to reach some "real" code. */ |
| |
| CORE_ADDR |
| merlin_skip_prologue (pc) |
| CORE_ADDR pc; |
| { |
| register int op = read_memory_integer (pc, 1); |
| if (op == 0x82) |
| { |
| op = read_memory_integer (pc + 2, 1); |
| if ((op & 0x80) == 0) |
| pc += 3; |
| else if ((op & 0xc0) == 0x80) |
| pc += 4; |
| else |
| pc += 6; |
| } |
| return pc; |
| } |
| |
| CORE_ADDR |
| umax_skip_prologue (pc) |
| CORE_ADDR pc; |
| { |
| register unsigned char op = read_memory_integer (pc, 1); |
| if (op == 0x82) |
| { |
| op = read_memory_integer (pc + 2, 1); |
| if ((op & 0x80) == 0) |
| pc += 3; |
| else if ((op & 0xc0) == 0x80) |
| pc += 4; |
| else |
| pc += 6; |
| } |
| return pc; |
| } |
| |
| /* Return number of args passed to a frame. |
| Can return -1, meaning no way to tell. */ |
| |
| int |
| merlin_frame_num_args (fi) |
| struct frame_info *fi; |
| { |
| int numargs; |
| CORE_ADDR pc; |
| int insn; |
| int addr_mode; |
| int width; |
| |
| pc = FRAME_SAVED_PC (fi); |
| insn = read_memory_integer (pc, 2); |
| addr_mode = (insn >> 11) & 0x1f; |
| insn = insn & 0x7ff; |
| if ((insn & 0x7fc) == 0x57c |
| && addr_mode == 0x14) /* immediate */ |
| { |
| if (insn == 0x57c) /* adjspb */ |
| width = 1; |
| else if (insn == 0x57d) /* adjspw */ |
| width = 2; |
| else if (insn == 0x57f) /* adjspd */ |
| width = 4; |
| numargs = read_memory_integer (pc + 2, width); |
| if (width > 1) |
| flip_bytes (&numargs, width); |
| numargs = -sign_extend (numargs, width * 8) / 4; |
| } |
| else |
| numargs = -1; |
| return numargs; |
| } |
| |
| |
| /* Return number of args passed to a frame. |
| Can return -1, meaning no way to tell. |
| Encore's C compiler often reuses same area on stack for args, |
| so this will often not work properly. If the arg names |
| are known, it's likely most of them will be printed. */ |
| int |
| umax_frame_num_args (fi) |
| struct frame_info *fi; |
| { |
| int numargs; |
| CORE_ADDR pc; |
| CORE_ADDR enter_addr; |
| unsigned int insn; |
| unsigned int addr_mode; |
| int width; |
| |
| numargs = -1; |
| enter_addr = ns32k_get_enter_addr ((fi)->pc); |
| if (enter_addr > 0) |
| { |
| pc = ((enter_addr == 1) |
| ? SAVED_PC_AFTER_CALL (fi) |
| : FRAME_SAVED_PC (fi)); |
| insn = read_memory_integer (pc, 2); |
| addr_mode = (insn >> 11) & 0x1f; |
| insn = insn & 0x7ff; |
| if ((insn & 0x7fc) == 0x57c |
| && addr_mode == 0x14) /* immediate */ |
| { |
| if (insn == 0x57c) /* adjspb */ |
| width = 1; |
| else if (insn == 0x57d) /* adjspw */ |
| width = 2; |
| else if (insn == 0x57f) /* adjspd */ |
| width = 4; |
| numargs = read_memory_integer (pc + 2, width); |
| if (width > 1) |
| flip_bytes (&numargs, width); |
| numargs = -sign_extend (numargs, width * 8) / 4; |
| } |
| } |
| return numargs; |
| } |
| |
| |
| sign_extend (value, bits) |
| { |
| value = value & ((1 << bits) - 1); |
| return (value & (1 << (bits - 1)) |
| ? value | (~((1 << bits) - 1)) |
| : value); |
| } |
| |
| void |
| flip_bytes (ptr, count) |
| char *ptr; |
| int count; |
| { |
| char tmp; |
| |
| while (count > 0) |
| { |
| tmp = *ptr; |
| ptr[0] = ptr[count - 1]; |
| ptr[count - 1] = tmp; |
| ptr++; |
| count -= 2; |
| } |
| } |
| |
| /* Return the number of locals in the current frame given a pc |
| pointing to the enter instruction. This is used in the macro |
| FRAME_FIND_SAVED_REGS. */ |
| |
| int |
| ns32k_localcount (enter_pc) |
| CORE_ADDR enter_pc; |
| { |
| unsigned char localtype; |
| int localcount; |
| |
| localtype = read_memory_integer (enter_pc + 2, 1); |
| if ((localtype & 0x80) == 0) |
| localcount = localtype; |
| else if ((localtype & 0xc0) == 0x80) |
| localcount = (((localtype & 0x3f) << 8) |
| | (read_memory_integer (enter_pc + 3, 1) & 0xff)); |
| else |
| localcount = (((localtype & 0x3f) << 24) |
| | ((read_memory_integer (enter_pc + 3, 1) & 0xff) << 16) |
| | ((read_memory_integer (enter_pc + 4, 1) & 0xff) << 8) |
| | (read_memory_integer (enter_pc + 5, 1) & 0xff)); |
| return localcount; |
| } |
| |
| |
| /* Nonzero if instruction at PC is a return instruction. */ |
| |
| static int |
| ns32k_about_to_return (pc) |
| CORE_ADDR pc; |
| { |
| return (read_memory_integer (pc, 1) == 0x12); |
| } |
| |
| |
| /* |
| * Get the address of the enter opcode for the function |
| * containing PC, if there is an enter for the function, |
| * and if the pc is between the enter and exit. |
| * Returns positive address if pc is between enter/exit, |
| * 1 if pc before enter or after exit, 0 otherwise. |
| */ |
| |
| CORE_ADDR |
| ns32k_get_enter_addr (pc) |
| CORE_ADDR pc; |
| { |
| CORE_ADDR enter_addr; |
| unsigned char op; |
| |
| if (pc == 0) |
| return 0; |
| |
| if (ns32k_about_to_return (pc)) |
| return 1; /* after exit */ |
| |
| enter_addr = get_pc_function_start (pc); |
| |
| if (pc == enter_addr) |
| return 1; /* before enter */ |
| |
| op = read_memory_integer (enter_addr, 1); |
| |
| if (op != 0x82) |
| return 0; /* function has no enter/exit */ |
| |
| return enter_addr; /* pc is between enter and exit */ |
| } |