| 1 | /* Target-dependent code for Lynx running on i386's, for GDB. |
| 2 | Copyright 1988, 1989, 1991, 1992, 1993 |
| 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "inferior.h" |
| 23 | #include "target.h" |
| 24 | |
| 25 | /* Return the PC of the caller from the call frame. Assumes the subr prologue |
| 26 | has already been executed, and the frame pointer setup. If this is the |
| 27 | outermost frame, we check to see if we are in a system call by examining the |
| 28 | previous instruction. If so, then the return PC is actually at SP+4 because |
| 29 | system calls use a different calling sequence. */ |
| 30 | |
| 31 | CORE_ADDR |
| 32 | i386lynx_saved_pc_after_call (frame) |
| 33 | struct frame_info *frame; |
| 34 | { |
| 35 | char opcode[7]; |
| 36 | static const char call_inst[] = {0x9a, 0, 0, 0, 0, 8, 0}; /* lcall 0x8,0x0 */ |
| 37 | |
| 38 | read_memory (frame->pc - 7, opcode, 7); |
| 39 | if (memcmp (opcode, call_inst, 7) == 0) |
| 40 | return read_memory_integer (read_register (SP_REGNUM) + 4, 4); |
| 41 | |
| 42 | return read_memory_integer (read_register (SP_REGNUM), 4); |
| 43 | } |